Infectious and Derm Flashcards

Question

Hep B

Answer 1

Double stranded DNA, Acute - Surface antigen, Anti Hbc, HBe antigen- high viral infectivity/replication, can go to fulminent - high serum transaminase, elivated bilirubin, Hep B core IgM (only marker in acute, liver failure) Chronic - (>6 months)10% goes to chronic, HbV Core IgM, core IgG, HBe antigen,Surface antigen, Asymptomatic, vague symptoms with affected liver HBV infects hepatocytes and replicates, triggering an immune response - leading to liver damage and potential complications like cirrhosis and liver cancer infected & imunized - no antigen, anti Hbc, Anti Hbs HBV can persist in the liver as covalently closed circular DNA (cccDNA) within the nucleus, allowing for long-term viral persistence. Chronic hepatitis B can lead to long-term liver damage, including fibrosis, cirrhosis, and an increased risk of liver cancer. Occult HBV infection refers to the presence of HBV DNA in the absence of detectable HBV surface antigen (HBsAg), often associated with strong viral suppression by the immune response. While HBsAg is not detectable, the presence of HBV DNA suggests ongoing viral persistence, and occult HBV infection can still contribute to liver disease progression. glomerular nephritis, myocardiits, polyartaritis - extra hepatic 70-90% chance of chronic infection in infants born to HBV-positive mothers complications Hepatocellular Carcinoma, Cirrhosis, Portal Hypertension Increased risk of B-cell non-Hodgkin lymphoma (NHL), - diffuse large B-cell lymphoma (DLBCL). Antiviral medications like entecavir and tenofovir Interferon, Supportive Care Management Aspect Key Recommendations Initial Assessment (Primary Care) For HBsAg-positive individuals: HBeAg/anti-HBe, HBV DNA, ALT, AST, tests for HCV, HDV, HIV; hepatic ultrasound & alpha-fetoprotein. Specialist Referral All HBsAg-positive individuals should be referred to a hepatologist or relevant specialist. Liver Disease Assessment Transient elastography (e.g., FibroScan) is the initial test for liver disease. Liver biopsy is considered for intermediate scores (6-10 kPa) or in specific cases with high viral load and abnormal ALT. Antiviral Treatment Criteria Based on combination of HBV DNA level, ALT level, and degree of liver fibrosis/cirrhosis. Treatment is strongly recommended for those with cirrhosis (elastography ≥11 kPa). First-Line Antiviral Therapy Nucleoside or nucleotide analogues (e.g., Tenofovir, Entecavir). Peginterferon alfa-2a is also an option in specific scenario

Answer 2

a condition where quinine, a drug used to treat malaria and leg cramps, can cause a decrease in platelets (thrombocytopenia) due to the formation of antibodies that recognize platelet membrane glycoproteins associated with hemolytic uremic syndrome (HUS) Quinine-dependent antibodies have been shown to react with red cells and granulocytes, potentially contributing to the development of HUS management - stopping quinine and supportive care (platelet)

Answer 3

Strong associations to age, UV exposure, fair skin, and weakened immune systems Presents as a painless, rapidly growing bump on the skin, often with a red, purple, or skin-colored appearance on sun-exposed areas Basal cell carcinoma or squamous cell carcinoma, can increase the risk of MCC. Certain medical conditions or treatments that suppress the immune system, such as chronic lymphocytic leukemia (CLL) or certain lymphomas, can also increase the risk.

Answer 4

usually asymptomatic unusual vaginal - often white, yellow, or gray, with a foul odor or penile discharge - clear, cloudy, or pus-like, burning during urination, and abdominal pain Testicular: Pain and swelling Conjunctivitis (pink eye) with redness, pain, and discharge Complications: PID in women, infertility and ectopic pregnancy Common STI, with young adults aged 15-24

Answer 5

haracterized by inflammation that obscures the dermo-epidermal junction and involves basal cell damage, often seen as apoptotic or necrotic keratinocytes involves an immune response, with plasmacytoid dendritic cells (pDCs) potentially playing a role in initiating the reaction by releasing cytokines like IFN-α. Trigger Factors - Contact Allergens, medications - antibiotics, antifungals, allopurinol, Hepatitis C virus and stress

Answer 6

Colonization of cardiac valve endocardium by virulent microorganisms. It is a rare condition that can lead to rapid and significant morbidity and mortality gram-positive streptococci, staphylococci, and enterococci infection - together 80% to 90% of all cases Fever, chills, and fatigue, joint and muscle pain, shortness of breath, and potentially a new or changing heart murmur. More specific signs, such as Osler's nodes, Janeway lesions, and Roth spots, are less common but can be indicative of immunologic phenomena. - A new or changing heart murmur, and the presence of splinter hemorrhages (small, linear hemorrhages under the fingernails or toenails).

Answer 7

Oral Lichen Planus (OLP) vs. Oral Lichenoid Lesions (OLLs): While OLP and OLLs share clinical and histological similarities, OLLs are often associated with identifiable inciting factors (e.g., drugs, dental restorations) that, when eliminated, can lead to lesion regression. Lichenoid Drug Eruptions (LDEs): LDEs can mimic lichen planus, but key differences include the presence of eosinophils and prominent parakeratosis on histology, which are less common in idiopathic lichen planus. A detailed medication history and potentially a challenge test (reintroducing the suspected drug) can aid in diagnosis. Other Immune-Mediated Mucocutaneous Diseases: Conditions like mucous membrane pemphigoid, chronic graft-versus-host disease, and lupus erythematosus can also exhibit lichenoid features, requiring a thorough clinical evaluation and potential biopsy. Lichenoid Keratosis: This condition, often arising in regressing solar or seborrheic keratoses, can be distinguished from lichen planus by its limited involvement (typically solitary or few lesions) and the absence of mucosal, nail, or hair follicle involvement.

Answer 8

a rare systemic vasculitis, meaning it causes inflammation of the small and medium-sized arteries, potentially leading to tissue damage. primarily affects medium-sized arteries Symptoms can include fever, fatigue, weight loss, abdominal pain, and neurological issues. Treatment often involves immunosuppressants like corticosteroids and cyclophosphamide.

Answer 9

an RNA virus Diagnosis - HCV antibodies & PCR(early detection), response to treatment Viral load associated - Hepatocellular Carcinoma - HCC, B-cell NHL, cancers of the bile ducts, pancreas, kidney, and lung, Porpiria cutania tarda, glomerular nephritis, cryioglobulinimia Chronic HCV infection, if left untreated, can progress to liver cirrhosis in up to 30% Acute Hepatitis C: a significant portion (85%) develop chronic infection. Acute HCV infection - jaundice, fatigue, nausea, and fever, commonly asymptomatcs. Fulminant Hepatitis: severe complication of acute HCV infection where the liver rapidly loses its function.less than 1% of cases. Chronic Hepatitis C: If left untreated, lead to a progressive scarring of the liver called cirrhosis. causes portal hypertension, variceal hemorrhages, ascites, and hepatic encephalopathy. Liver Failure: Hepatocellular Carcinoma (HCC): higher risk of developing HCC Direct-acting antiviral (DAA) tablets- 90% curable - short (8-12 weeks) pecific DAA Classes: NS3/4A Protease Inhibitors: grazoprevir, simeprevir, and voxilaprevir, target the NS3/4A protease enzyme, which is essential for viral replication. NS5A Inhibitors: daclatasvir and velpatasvir, block the NS5A protein, which plays a crucial role in viral replication. Nucleotide/Nucleoside Polymerase Inhibitors: Sofosbuvir Fixed-Dose Combinations: Harvoni (ledipasvir/sofosbuvir). Zepatier (elbasvir/grazoprevir). Epclusa (sofosbuvir/velpatasvir). Vosevi (sofosbuvir/velpatasvir/voxilaprevir). Mavyret (glecaprevir/pibrentasvir).

Answer 10

involves both direct cytopathic effects and host immune responses. Fulminent, Hepatoma HDV, a defective RNA virus, requires hepatitis B virus (HBV) for replication and transmission, typically occurring as a coinfection or superinfection. Hepatitis D is a defective RNA virus that requires Hepatitis B surface antigen (HBsAg) to replicate. It causes acute or chronic liver disease only in individuals with HBV coinfection. A. Acute Hepatitis D Coinfection (HBV + HDV): Similar to acute HBV but more severe (higher risk of fulminant hepatitis). Superinfection (HDV in HBV carrier): Acute exacerbation of chronic HBV → fulminant liver failure. B. Chronic Hepatitis D Rapid progression to cirrhosis (within 5–10 years in 70–80% of cases). Symptoms: Fatigue, jaundice, ascites, hepatic encephalopathy. Higher risk of HCC than HBV alone. Diagnosis A. Serologic Markers Test Interpretation HBsAg # Must be positive (HDV cannot infect without HBV). Anti-HDV IgM/IgG # IgM = acute infection; IgG = chronic/past infection. HDV RNA PCR # Confirms active replication (gold standard). Liver Biopsy/Fibroscan Assess fibrosis/cirrhosis (HDV causes severe necroinflammation). Treatment A. Current Options (Limited Efficacy) Pegylated Interferon-α (PEG-IFN) 48 weeks of therapy (only 25–30% achieve sustained virologic response). Side effects: Flu-like symptoms, depression, cytopenias. Nucleos(t)ide Analogs (e.g., Tenofovir/Entecavir) Suppress HBV but do NOT treat HDV directly (must still be given to control HBV). B. Emerging Therapies (2023 Updates) Bulevirtide (Myrcludex B) – First approved HDV drug (EU, 2020): Blocks HDV entry into hepatocytes. ✅ HDV requires HBV to replicate (always test HBV patients for HDV). ✅ Superinfection is worse than coinfection (rapid cirrhosis). ✅ PEG-IFN is mainstay but poorly effective (bulevirtide is promising). ✅ No cure – focus on preventing HBV/HDV transmission.

Answer 11

-Gram-positive, spherical (cocci) bacterium, typically forming grape-like clusters, and is a common inhabitant of the skin and mucosa, indwelling urinary catheters, central venous catheters, severe infections in newborns Treatment - antibiotics like Vancomycin Boils, carbuncles, and abscesses, Cellulitis, Impetigo, Endocarditis, Osteomyelitis, Pneumonia

Answer 12

It involves taking a combination of antiretroviral drugs for 28 days, ideally started within 24 hours but no later than 72 hours after the exposure

Answer 13

Bacteria are the most common cause of travellers' diarrhoea. Overall, the most common pathogen is enterotoxigenic Escherichia coli, followed by Campylobacter jejuni, Shigella spp., and Salmonella spp. Therefore, the answer is E. coli (enterotoxigenic) because it is the most likely cause of the presentation. appear within 2 to 8 days after exposure, with a typical onset around 3 to 4 days. incubation period - 1 day to as long as 10 days.

Answer 14

a common herpesvirus infection that typically causes no symptoms in healthy individuals In pregnant women, a CMV infection can lead to congenital CMV - congenital CMV can cause hearing loss, vision problems, developmental delays, and neurological problems in infants. mmunocompromised individuals: CMV can cause serious illness in people with weakened immune systems, such as organ transplant recipients or individuals with HIV/AIDS, potentially affecting multiple organs. Ganciclovir and Valganciclovir - only for immunocompromised No approved treatment during pregnancy. confirmed fetal CMV infection, regular ultrasound and MRI scans are recommended to monitor the fetus. If the baby is born with symptoms, antiviral treatment may be given to improve outcomes

Answer 15

Norovirus is the most common cause of viral gastroenteritis. It is transmitted by faecally contaminated food or water, by person-to-person contact, and via aerosolisation of vomited virus and subsequent contamination of surfaces. Outbreaks in cruise ships are common. incubation period of 12 to 48 hours resolves within 1 to 3 days.

Answer 16

Listeria monocytogenes is a Gram-positive, facultative intracellular bacterium causing foodborne infections, particularly dangerous for pregnant women, neonates, elderly, and immunocompromised individuals. B. Key Features Meningitis: Often atypical (subacute, low CSF WBCs, high protein). Rhombencephalitis (brainstem encephalitis): Ataxia, cranial nerve palsies. Granulomatosis infantiseptica (neonates): Diffuse microabscesses. 2. Diagnosis A. Laboratory Testing Culture (Gold standard): Blood, CSF, placenta, meconium (neonates). Grows on standard media but cold-enrichment improves yield. PCR (CSF/tissue samples for rapid diagnosis). CSF Analysis (Listeria meningitis): Moderate pleocytosis (often <1,000 cells/µL, mixed neutrophils/lymphocytes). Gram stain may show faint Gram-positive rods (30–40% sensitivity). B. Imaging (CNS Involvement) MRI Brain: Ring-enhancing abscesses, brainstem hyperintensity (rhombencephalitis). C. Differential Diagnosis Other bacterial meningitis (GBS, S. pneumoniae). Toxoplasmosis, HSV encephalitis. 3. Treatment (IDSA/UK Guidelines) A. First-Line Therapy Ampicillin 2g IV every 4h + Gentamicin 1mg/kg every 8h (synergistic for severe infections). Penicillin-allergic: Trimethoprim-sulfamethoxazole (TMP-SMX) 15–20mg/kg/day IV. B. Duration Meningitis/Brain abscess: 3–6 weeks. Bacteremia: 14 days. Pregnant women: 10–14 days (ampicillin alone often sufficient). C. Neonatal Management Ampicillin + Gentamicin × 14–21 days (longer for meningitis). types Non-Invasive Listeriosis: Healthy individuals often experience a mild, self-limiting gastroenteritis with symptoms like fever, diarrhea, nausea, vomiting, and muscle aches. Invasive Listeriosis: This is a more severe form of the disease that can lead to life-threatening complications. Symptoms may include fever, chills, headache, stiff neck, confusion, and convulsions. Listeriosis - mild or asymptomatic in the mother - to fetus miscarriage, stillbirth, preterm labor, or neonatal infection - Neonatal listeriosis can be classified as early (within 6 days of birth)- Granulomatosis Infantiseptica severe disease - Sepsis, Meningitis and Encephalitis, Focal Infections Risk Factors: Pregnancy, Immunocompromised Individuals, Elderly, Neonates ✅ Pregnant women: Flu-like illness → check for Listeria (fetal risk high). ✅ Meningitis in elderly/immunocompromised? Think Listeria (atypical CSF findings). ✅ Ampicillin + Gentamicin = 1st-line for severe infections. ✅ Avoid high-risk foods in pregnancy & immunosuppression.

Answer 17

RNA, Hep E infections are asymptomatic acute hepatitis, chronic hepatitis, or acute on chronic liver failure, especially in immunocompromised individuals or pregnant women Diagnostic Tools: Serological Tests: anti-HEV IgM Molecular Tests: RT-PCR - HEV RNA in blood and stool, Liver Biopsy: assess the histopathological changes to differentiate Ribaverin in some cases

Answer 18

Liver damage is primarily caused by the body's immune response, not directly by the virus itself. HAV infection is usually self-limiting, and most patients recover fully without chronic liver disease. Individuals with pre-existing liver disease, such as chronic hepatitis B or C, are at higher risk of developing fulminant hepatitis A

Answer 19

Meningococcemia: Invasive meningococcal disease, particularly meningococcemia, can lead to a severe inflammatory response, including: Endotoxins: The bacteria's endotoxins trigger an intense inflammatory reaction, leading to the release of cytokines and other inflammatory mediators. Vascular Damage: Inflammation damages blood vessel walls, causing increased vascular permeability, bleeding (petechiae or purpura), and potential shock. Disseminated Intravascular Coagulation (DIC): DIC, a life-threatening condition, can occur due to the widespread activation of the coagulation cascad Meningitis: Host Immune Response Septic arthritis, pneumonia, pericarditis, conjunctivitis, otitis, sinusitis, and urethritis. A rare chronic meningococcemia syndrome with fever, rash, joint aches, and headache. Purpura fulminans, a severe form of meningococcemia, can lead to tissue necrosis and amputation. hird-generation cephalosporin (ceftriaxone or cefotaxime) or penicillin.

Answer 20

Skin and Soft Tissue Infections: Boils (furuncles), Cellulitis: , Impetigo, Folliculitis, Carbuncles, Staphylococcal Scalded Skin Syndrome: Bacteremia: lead to sepsis Infective Endocarditis: Osteomyelitis Pneumonia Toxic Shock Syndrome (TSS): A rare but severe illness caused by toxins produced by certain S. aureus strains, characterized by high fever, rash, and organ failure. Food Poisoning: Mastitis: breast feedings Meningitis Prosthetic Device Infections Urinary Tract Infections MRSA: Methicillin-resistant Staphylococcus aureus (MRSA)

Answer 21

Diarrhea: This is the most prominent symptom, often described as watery, foul-smelling, and greasy. Abdominal Cramps and Pain, Nausea and Vomiting, Gas and Bloating, Loss of Appetite and Weight Loss: , significant weight loss can occur. Dehydration Giardia parasite or by using molecular tests to detect parasite antigens or DNA. antibiotics, most commonly metronidazole or tinidazole.

Answer 22

Infection and Initial Replication: Humans are infected by ingesting oocysts from cat feces, or by consuming tissue cysts in infected meat. Inside the host, the parasite transforms into tachyzoites, which actively replicate within cells. Tachyzoites cause cell damage, inflammation, and necrosis. 2. Host Immune Response and Cyst Formation: The host's immune system, particularly cell-mediated immunity, helps control the infection. Tachyzoites are converted into bradyzoites, which form tissue cysts in various organs, especially the brain, eyes, and muscles. Cysts can persist for life, remaining dormant in most individuals with a healthy immune system. 3. Reactivation and Disease: In individuals with compromised immune systems (e.g., AIDS patients), tissue cysts can reactivate. Reactivated bradyzoites transform back into tachyzoites, which cause disease, particularly encephalitis and other systemic infections. The severity of disease depends on the extent of organ damage, especially in vital organs like the brain and eyes.

Answer 23

2. Clinical Presentation A. Classic Triad (50–70% of Cases) Fever (>38°C). Neck stiffness (nuchal rigidity, Kernig’s/Brudzinski’s signs). Altered mental status (confusion, lethargy, coma). B. Other Key Symptoms Headache (severe, sudden onset). Photophobia, vomiting. Petechial/purpuric rash (N. meningitidis – medical emergency). Seizures (20–30%, especially pneumococcal). C. Atypical Presentations Elderly: May lack fever/stiffness (altered mentation only). Infants: Bulging fontanelle, irritability, poor feeding. 3. Diagnosis A. Immediate Workup Lumbar Puncture (LP) with CSF Analysis (Do not delay antibiotics for imaging if no contraindications!). Contraindications to LP: Signs of raised ICP (papilledema, focal neurology, GCS <10). Coagulopathy/thrombocytopenia (platelets <50k, INR >1.5). CT before LP if: Immunocompromised, seizure, focal deficit, or papilledema. CSF Findings in Bacterial Meningitis | Parameter | Normal CSF | Bacterial Meningitis | |---------------------|--------------------|--------------------------------| | Opening Pressure | 5–20 cmH₂O | Elevated (>25 cmH₂O) | | WBC Count | 0–5 cells/µL | 100–10,000/µL (PMN-predominant) | | Glucose | >2/3 serum glucose | Low (<40 mg/dL or <1/2 serum) | | Protein | 15–45 mg/dL | High (>100 mg/dL) | | Gram stain | Negative | Positive in 60–90% (if untreated) | Blood Tests CBC: Leukocytosis with left shift. CRP/PCT: Elevated. Blood cultures (positive in 50–80%). PCR (If CSF Gram stain negative but clinical suspicion high). Emergency Management A. Empiric Antibiotics (Start Within 1 Hour!) Patient Group Empiric Regimen Neonates Ampicillin + Cefotaxime (or Gentamicin) Children/Adults Ceftriaxone 2g IV + Vancomycin (if pneumococcal resistance suspected) Elderly (>50yo)/Immunocompromised Ampicillin + Ceftriaxone + Vancomycin (covers Listeria) Post-neurosurgery/TBI Vancomycin + Ceftazidime/Meropenem (covers Pseudomonas, MRSA) B. Adjunctive Therapy Dexamethasone 10mg IV (adults) / 0.15mg/kg (children) before/with antibiotics: Reduces mortality in S. pneumoniae meningitis. Controversial in meningococcal meningitis. C. Supportive Care IV fluids (avoid hyponatremia). Seizure control (benzodiazepines, levetiracetam). ICP management (elevate head, mannitol/hypertonic saline if herniation). 5. Complications Cerebral edema, herniation. Hearing loss (10–30% of pneumococcal cases). Septic shock, DIC (meningococcal). Venous sinus thrombosis, hydrocephalus. ✅ Triad: Fever + neck stiffness + altered mentation (but often incomplete). ✅ LP is diagnostic (do not delay antibiotics for imaging unless contraindicated). ✅ Empiric therapy depends on age/risk factors: Ceftriaxone + Vancomycin (most adults). Add Ampicillin if Listeria risk (age >50, immunocompromised). ✅ Dexamethasone before antibiotics for suspected pneumococcal meningitis.

Answer 24

Acute inflammation of the brain parenchyma caused by viral infection, leading to fever, altered mental status, and neurological deficits. Virus Key Features Herpes Simplex (HSV-1) Most common sporadic cause (temporal lobe involvement → seizures, personality changes). Varicella-Zoster (VZV) May present with vasculopathy or multifocal lesions. Enteroviruses Common in children; often mild, but severe in neonates. Arboviruses West Nile, Japanese encephalitis, Tick-borne (TBE) – vector-borne, seasonal. HIV (Early or Advanced) Can cause acute retroviral syndrome or opportunistic infections (CMV, PML). 2. Clinical Presentation A. Classic Triad (Not Always Present) Fever (75% of cases). Altered mental status (confusion, lethargy, coma). Headache (severe, progressive). B. Other Symptoms Seizures (focal or generalized). Focal neurological deficits (aphasia, hemiparesis). Behavioral changes (aggression, psychosis – HSV-1 temporal lobe involvement). Meningismus (neck stiffness, photophobia – if meninges involved). 3. Diagnosis A. Immediate Workup MRI Brain (Gold Standard) HSV-1: Temporal lobe hyperintensity (T2/FLAIR), hemorrhagic changes. VZV: Multifocal white matter lesions, vasculitis. West Nile: Basal ganglia/thalamus involvement. Lumbar Puncture (LP) & CSF Analysis Opening pressure: Often elevated. CSF Findings: Parameter Viral Encephalitis Bacterial Meningitis WBC Count #10–500 cells/µL (lymphocytic) #100–10,000 (PMN-predominant) Glucose #Normal #Low Protein #Mildly elevated (50–200 mg/dL) #High (>100 mg/dL) PCR for HSV/VZV/Enterovirus (CSF) – most sensitive. Serology (Arboviruses, HIV). EEG Periodic lateralized epileptiform discharges (PLEDs) in HSV encephalitis. B. Differential Diagnosis Autoimmune encephalitis (anti-NMDA, LGI1 antibodies). Bacterial meningitis, brain abscess. Metabolic/toxic encephalopathy. 4. Emergency Management A. Empiric Therapy (Start Immediately!) HSV/VZV Suspected: Acyclovir IV 10mg/kg q8h (HSV) + consider adjunctive steroids (if vasculitis suspected). Duration: 14–21 days (HSV), longer if immunocompromised. Arbovirus/Enterovirus Suspected: Supportive care (no specific antiviral). Immunocompromised Patients: CMV: Ganciclovir. PML (JC virus): Immune reconstitution (if HIV). B. Supportive Care Seizure control (levetiracetam preferred). ICP management (head elevation, hypertonic saline if severe edema). ICU monitoring if GCS ≤8. 5. Complications Long-term cognitive deficits (memory loss, executive dysfunction). Epilepsy (20–30% post-HSV encephalitis). Movement disorders (post-arbovirus infection). 6. Key Takeaways ✅ HSV-1 is the most common cause – temporal lobe MRI changes + CSF PCR confirm. ✅ Start IV acyclovir immediately if HSV suspected (delays increase mortality). ✅ CSF lymphocytosis + normal glucose suggests viral (not bacterial) etiology. ✅ Autoimmune encephalitis mimics viral – check NMDA/LGI1 antibodies if PCR negative.

Answer 25

affects almost the entire body, causing a red rash, intense itching, and potentially life-threatening complications like heart failure or infection Redness and inflammation: intensely red and inflamed, often resembling a burn. Scaly skin: Skin peeling: peel off in large sheets, leading to a loss of skin barrier. Itching and burning: Nail changes: brittle or fall off. Systemic symptoms: Fever, chills, fatigue, and a rapid heartbeat Unstable psoriasis: Erythrodermic psoriasis often occurs in people with unstable plaque psoriasis. Medications: Withdrawal of oral or topical corticosteroids, or starting or stopping other medications can trigger it. Infections: Severe illnesses or infections can also trigger the condition. Stress: Stress may also play a role in triggering erythrodermic psoriasis. Initial treatment is with topical white soft paraffin smeared all over the skin, which helps to make the skin more comfortable, partially reduces the inflammation, improves the skin barrier (which is generally defective in erythroderma), thus helping to prevent entry of bacteria through the skin (and prevent septicaemia), and helps to reduce water loss from the skin (and prevent dehydration). While using topical white soft paraffin, relevant investigations can be performed to determine the cause of the erythroderma and to determine which systemic therapy can be employed to treat the cause of the erythroderma. Treat underline & supportive care Immunosuppressants like methotrexate, acitretin, or cyclosporine ustekinumab and ixekizumab Topical corticosteroids

Answer 26

A zoonotic bacterial infection caused by Brucella spp. (B. melitensis, B. abortus, B. suis, B. canis). is a bacterial disease primarily affecting cattle and other animals, but can also infect humans. Reservoirs: B. melitensis (goats/sheep) – most virulent. B. abortus (cattle), B. suis (pigs), B. canis (dogs). A. Acute Brucellosis (90% of Cases) Undulant fever (high spikes evenings, drenching sweats). Arthralgia/arthritis (sacroiliitis, spondylitis). Hepatosplenomegaly, lymphadenopathy. Fatigue, anorexia, weight loss ("chronic fatigue" presentation). B. Focal Complications (10–40%) System Manifestations Osteoarticular Sacroiliitis, spondylitis (vertebral osteomyelitis). Genitourinary Orchitis, epididymitis (mimics TB). Neurologic Meningoencephalitis, peripheral neuropathy. Cardiovascular Endocarditis (culture-negative, high mortality). Hepatic Granulomatous hepatitis. C. Chronic Brucellosis Symptoms >1 year; mimics lymphoma/TB. 3. Diagnosis A. Laboratory Testing Culture (Gold standard but slow): Blood, bone marrow, CSF (prolonged incubation; BACTEC improves yield). Serology: Rose Bengal test (rapid screening). SAT (Standard Agglutination Test) – Titers ≥1:160 suggest active infection. ELISA/Coomb’s test (for chronic cases). PCR (rapid but not widely standardized). Adults & Children >8 Years Doxycycline 100mg PO BID × 6 weeks + Rifampin 600–900mg PO daily × 6 weeks. Alternative: Doxycycline + streptomycin/gentamicin (first 2–3 weeks). B. Pregnant Women/Children <8 Years TMP-SMX + Rifampin (avoid doxycycline/aminoglycosides). ✅ Undulant fever + arthralgia + animal exposure → suspect brucellosis. ✅ SAT ≥1:160 or blood culture confirms diagnosis. ✅ Doxycycline + rifampin × 6 weeks (aminoglycosides for severe cases). ✅ Endocarditis/spondylitis require prolonged therapy ± surgery. Wet hay smell

Answer 27

Borrelia burgdorferi Symptoms: Erythema migrans: A circular or oval rash around the tick bite, often described as a "bullseye" rash, is a hallmark of early Lyme disease. Fever, headache, and fatigue: These are common early symptoms. Joint pain: Arthritis can develop in later stages of Lyme disease. Other symptoms: Depending on the stage and severity of the infection, Lyme disease can cause a range of symptoms, including neurological problems, heart complications, and skin conditions. Neuro - 10% Facial Palsy/Bell's Palsy: Weakness or paralysis on one side of the face, potentially causing trouble closing the eye, drooping smile, or drooling. Meningitis-like Symptoms: Headache, stiff neck, fever, and sensitivity to light. Visual Disturbances: Double vision, blurry vision, or other changes in vision. Numbness, Pain, and Weakness: Sensory disturbances or weakness in the extremities or other parts of the body. Cognitive Difficulties: Brain fog, memory loss, difficulty concentrating, and impaired executive function. Sleep Disturbances: Insomnia or other sleep problems. Hearing Loss and Dizziness: Possible as a result of cranial nerve involvement. Pain and Stiffness: Muscle aches, joint pain, and a stiff neck can be associated with Lyme disease.

Answer 28

squamous cell carcinoma in situ (SCC in situ) red, scaly, or crusty patch on the skin, often found on sun-exposed areas. Red, scaly, or crusty patches on the skin May be itchy but often isn't Can be flat or slightly raised May be single or multiple patches Typically on sun-exposed areas like the face, hands, and lower legs

Answer 29

dentified with keratinization, keratin pearls and intercellular bridges Poorly differentiated lesions may lose morphologic features of squamous differentiation and require IHC to separate from other non-small lesions, p40 positivity will help Primary and metastatic tumors have an overlapping morphology and immunohistochemical profiles; in most cases it is not possible to determine the primary site of squamous cell carcinoma Strong association with history of tobacco smoking over 50 years of age 85% of primary lung cancers are non-small cell carcinomas and squamous cell makes up 30% of these cases

Answer 30

Symptoms include diarrhea, abdominal pain, and sometimes fever. The bacteria are typically acquired through eating contaminated food, especially raw or undercooked pork. Mimicking appendicitis: Right-sided abdominal pain and fever can be mistaken for appendicitis. - "cluster of lymph nodes at appendix suggestive of mesenteric adenitis" points more to yersinia infection, which can mimic Crohn's disease and appendicitis (pseudoappendicitis). Other possible complications: In some cases, yersiniosis can cause skin rash, joint pain, or even spread to the bloodstream. Reactive arthritis: Joint pain, most commonly in the knees, ankles, or wrists, can develop 1-2 weeks after the gastrointestinal illness.

Answer 31

multi-drug therapy (MDT), a combination of antibiotics, including dapsone, rifampicin, and clofazimine

Answer 32

a common viral skin infection causing small, raised, flesh-colored, white, or pink bumps on the skin. These bumps are usually harmless and will typically clear up on their own within 6 to 18 months without treatment poxvirus usually flesh-colored, white, or pink, with a shiny, dome-shaped appearance and a central dimple.

Answer 33

ype of skin cancer that develops from melanocytes, the cells that produce melanin, giving skin its color. It's a serious cancer that can spread to other parts of the body existing mole or the appearance of a new mole, especially those that are asymmetrical, have irregular borders, varying colors, or are larger than 6 millimeters, are potential signs of melanoma. Clinical Presentation and Diagnosis The ABCDE guide helps identify suspicious lesions: Asymmetry Irregular Borders Color variations Diameter >6mm Evolving characteristics Surgery is the primary treatment for melanoma, and it can also involve other therapies like radiation therapy, immunotherapy, or targeted therapy. Lentigo maligna is a specific type of melanoma in situ, an early form of melanoma where the cancerous cells are confined to the top layer of the skin (epidermis). It typically appears as a slowly growing, brown patch, often on areas of chronic sun exposure like the head and neck - surgical excision, where the lesion and a surrounding margin of normal skin are removed- 1cm. - -Systemic Therapies Immunotherapy (key agents): Checkpoint inhibitors: Nivolumab, pembrolizumab (anti-PD-1); ipilimumab (anti-CTLA-4) Combination therapies: Nivolumab + relatlimab (LAG-3 inhibitor) Cytokine therapy: Aldesleukin (IL-2) Targeted therapy (for BRAF-mutant melanomas): BRAF inhibitors: Dabrafenib, vemurafenib MEK inhibitors: Trametinib Combination approaches (BRAF+MEK inhibitors) Treatment by Stage Early-stage (I-II): Wide local excision with appropriate margins Consider adjuvant therapy for high-risk stage IIB/IIC Stage III (locoregional metastasis) Surgical resection + lymph node dissection Adjuvant immunotherapy (nivolumab, pembrolizumab) or targeted therapy (for BRAF mutants) Neoadjuvant immunotherapy showing promise (ipilimumab + nivolumab) Stage IV (metastatic): First-line: Combination immunotherapy (nivolumab + ipilimumab) or anti-PD-1 monotherapy BRAF/MEK inhibitors for BRAF-mutant cases Paradigm Shifts Neoadjuvant therapy: NADINA trial showed bi-immunotherapy (ipilimumab + nivolumab) before surgery outperformed adjuvant monotherapy 5

Answer 34

a subset of aggressive skin and soft tissue infections that cause muscle fascia and subcutaneous tissue necrosis. The infection typically travels along the fascial plane, which has a poor blood supply Early Signs (Days 1-2): Local Pain and Swelling: The infected area becomes intensely painful and swollen, often disproportionately to the observed changes. Erythema: The skin around the infection site turns red, warm, and shiny. Systemic Signs: Flu-like symptoms like fever, chills, nausea, and diarrhea may develop. Intermediate Signs (Days 3-5): Skin Changes: The erythema may progress to a purplish or bluish-gray hue, with the skin becoming indurated and swollen. Pain and Sensory Changes: While initially severe, pain may decrease as nerve damage occurs due to tissue necrosis. Skin Breakdown: Blisters, bullae, and even black, dead tissue (gangrene) may become visible. Systemic Progression: Patients may experience tachycardia, dehydration, and a worsening of flu-like symptoms. Late Signs (Days 4-5 and beyond): Severe Systemic Illness: The infection may enter the bloodstream, leading to sepsis and toxic shock. Altered Mental Status: The patient may become confused, disoriented, or even lose consciousness. Organ Damage: In some cases, the infection can spread to other organs like the liver, spleen, or lung Rapid Progression: Necrotizing fasciitis progresses rapidly, and early diagnosis and treatment are crucial. Differential Diagnosis: It's important to differentiate necrotizing fasciitis from other soft tissue infections like cellulitis or erysipelas. Surgical debridgment, IV antibiotic

Answer 35

a thick, gray membrane in the throat and tonsils, along with symptoms like sore throat, fever, and swollen neck glands. Sore throat: This is a common early symptom. Fever: Often a low-grade fever. Swollen neck glands: Known as cervical lymphadenopathy. Membrane formation: A thick, gray pseudomembrane develops in the throat, tonsils, and possibly the nose, making breathing and swallowing difficult. Bull's neck: In severe cases, swelling of the neck can cause a "bull's neck" appearance. Respiratory distress: Difficulty breathing, hoarseness, and a bark-like cough can occur. Systemic effects: The diphtheria toxin can spread through the bloodstream, leading to heart and nerve damage. Cutaneous Diphtheria: Skin lesions: May appear as ulcers with a gray membrane, or as a scaling rash. Pain, redness, and swelling: Similar to other skin infections. Slow healing: Skin lesions in cutaneous diphtheria are slow to heal. toxigenic diphtheria 1. Cardiac Complications: Myocarditis- major concern in diphtheria, potentially leading to heart failure and arrhythmias. Arrhythmias, Pericarditis, Endocarditis Neurological Complications: Polyneuropathy, Cranial Nerve Palsy, Demyelinating Polyneuropathy, Bulbar Palsy, Diaphragmatic Paralysis Treatment (WHO & UK Guidelines) A. Antitoxin (DAT – Diphtheria Antitoxin) Single dose IV/IM (20,000–100,000 units based on severity). Must be given before toxin binds tissues (no effect after binding). B. Antibiotics Erythromycin (PO/IV) or Penicillin G (IV) × 14 days. Macrolides preferred (better mucosal penetration). C. Supportive Care Airway management (intubation if obstruction). Cardiac monitoring (myocarditis risk). Post-Exposure Prophylaxis Close contacts: Erythromycin × 7–10 days. Vaccine booster if last dose >5 years ago. ✅ Pseudomembrane + bull neck = Classic presentation. ✅ DAT must be given early (before toxin binds). ✅ Notify public health immediately (highly contagious). ✅ Vaccination prevents outbreaks (UK cases rare due to immunisation).

Answer 36

MSF is caused by Rickettsia rickettsii and transmitted by ticks like the American dog tick and Rocky Mountain wood tick, while Lyme disease is caused by Borrelia burgdorferi and transmitted primarily by the blacklegged tick Rocky Mountain Spotted Fever (RMSF) Cause: Rickettsia rickettsii Transmission: American dog tick, Rocky Mountain wood tick, and brown dog tick Symptoms: Fever, headache, muscle aches, and a rash that typically starts on the wrists and ankles and spreads. Some people may not develop a rash. Severity: RMSF can be severe and potentially fatal if not treated promptly with antibiotics, particularly doxycycline. Treatment: Doxycycline is the primary treatment for RMSF. Mortality: RMSF has a higher mortality rate than Lyme disease. Lyme Disease Cause: Borrelia burgdorferi Transmission: Primarily by the blacklegged (deer) tick. Symptoms: Fatigue, fever, headache, stiff neck, and a characteristic rash called erythema migrans, often a bullseye-like pattern. Severity: Lyme disease can lead to long-term health complications if left untreated. Treatment: Lyme disease is treated with antibiotics, such as doxycycline, amoxicillin, or ceftin. Mortality: Lyme disease has a lower mortality rate than RMSF.

Answer 37

an cause painful ulcers in the rectum, leading to proctitis, which is inflammation of the rectum.

Answer 38

infectious mononucleosis (mono) or glandular fever, Infectious Mononucleosis (Mono): The most well-known EBV-related illness, characterized by fatigue, fever, sore throat, and swollen lymph nodes. No antibiotics - maculopapular preuretic rash associated with amoxicilin 99% EBV is associated with a range of conditions, including certain cancers (like Burkitt's lymphoma and nasopharyngeal cancer), post-transplant lymphoproliferative disease, and chronic active EBV infection - epihelial cancers

Answer 39

Plasmodium falciparum: This species is the most dangerous, leading to severe and potentially fatal malaria. It is found in Africa and other parts of the world. - Artemisinin-based combination therapy (ACT) artesunate-mefloquine, artemether-lumefantrine (Coartem), artesunate-amodiaquine, dihydroartemisinin-piperaquine, and artesunate-sulfadoxine-pyrimethamine. Plasmodium vivax: This species is prevalent in many regions, including parts of South America and Asia. While less severe than P. falciparum, it can cause relapses due to dormant forms in the liver. - Primaquine, Chloroquine Plasmodium malariae: This species causes chronic malaria infections. Plasmodium ovale: This species can remain latent in the liver for many years, causing relapses. Plasmodium knowlesi: This species is found in Southeast Asia and can cause severe disease.

Answer 40

branching pattern of the ulcer makes it easily recognizable when stained with fluorescein dye. dendritic ulcers may experience pain, light sensitivity (photophobia), a gritty or foreign-body sensation in the eye, redness, and blurred vision. Fluorescein staining is a crucial diagnostic tool Antiviral medications, like Ganciclovir

Answer 41

SCHATE S: ilicosis & Sarcoidosis: Both can cause upper lobe fibrosis. C: oalworker's lung: A pneumoconiosis that often affects the upper lobes. H: istiocytosis: Specifically, Langerhans cell histiocytosis (eosinophilic granuloma) can present with upper lobe fibrosis. A: nkylosing spondylitis & Allegic Bronchopulmonary Aspergillosis (ABPA): These conditions can also lead to fibrosis in the upper lobes. T: uberculosis: TB, especially healed or chronic cases, can cause upper lobe fibrosis. SCARAB S ystemic sclerosis: A connective tissue disease that can cause lower lobe fibrosis. C ryptogenic fibrosing alveolitis: A type of idiopathic pulmonary fibrosis that often affects the lower lobes. A miodarone & other drugs: Many medications, like amiodarone, can cause drug-induced lung fibrosis, often in the lower lobes. R eumatoid arthritis: A connective tissue disease that can cause rheumatoid arthritis-associated interstitial lung disease, often with lower lobe involvement. A sbestosis: Exposure to asbestos can lead to lower lobe fibrosis. B ronchiectasis: An abnormal dilation of the airways, often associated with lower lobe fibrosis.

Answer 42

a parasitic infection caused by Toxoplasma gondii, a protozoan with worldwide distribution. While often asymptomatic in immunocompetent individuals, it can cause severe disease in fetuses (congenital toxoplasmosis) and immunocompromised patients (e.g., HIV/AIDS, transplant recipients)(CD4 <100 cells/µL → reactivation). Clinical Features A. Immunocompetent Individuals (90% Asymptomatic) Acute infection: Flu-like illness (fever, lymphadenopathy, fatigue). Cervical lymphadenopathy (most common sign). Ocular toxoplasmosis (retinochoroiditis): Blurred vision, floaters, photophobia. B. Congenital Toxoplasmosis Classic triad: Chorioretinitis. Hydrocephalus. Intracranial calcifications. Other manifestations: Jaundice, hepatosplenomegaly, seizures. C. Immunocompromised Patients CNS toxoplasmosis (most common): Headache, confusion, focal neurologic deficits, seizures. Ring-enhancing brain lesions on MRI. Disseminated disease: Pneumonia, myocarditis. 3. Diagnosis A. Serology (Primary Tool) Test Interpretation IgM+ Acute/recent infection. IgG+ (low avidity) Recent infection (<3 months). IgG+ (high avidity) Past infection (immunity). B. Direct Detection PCR (blood, CSF, amniotic fluid – gold standard for congenital/CNS cases). Tissue biopsy (rare; shows tachyzoites/bradyzoites). C. Imaging MRI Brain: Multiple ring-enhancing lesions (HIV patients). Fetal Ultrasound: Hydrocephalus, intracranial calcifications. Treatment A. Immunocompetent Patients Usually self-limiting (no treatment needed). Severe cases: Pyrimethamine + sulfadiazine + leucovorin × 2–4 weeks. B. Congenital Infection Prenatal (maternal): Spiramycin (reduces fetal transmission). Postnatal (infant): Pyrimethamine + sulfadiazine + leucovorin × 12 months. C. Immunocompromised Patients Induction: Pyrimethamine 200mg loading dose, then 50mg/day + Sulfadiazine 1g QID + Leucovorin 10–25mg/day (prevents bone marrow toxicity). Duration: 6 weeks (CNS), then maintenance. Maintenance (HIV): TMP-SMX DS 1 tab daily (prevents relapse until CD4 >200). D. Ocular Toxoplasmosis Pyrimethamine + sulfadiazine + steroids (if vision threatened). Pyrimethamine and Sulfadiazine: This is a common combination used to treat active infections, often combined with folinic acid (leucovorin) to reduce side effects, Other options may include clindamycin, azithromycin, or trimethoprim-sulfamethoxazole, depending on the individual's situation and tolerance, ✅ Asymptomatic in most; lymphadenopathy in acute cases. ✅ Congenital infection → chorioretinitis, hydrocephalus. ✅ CNS lesions in HIV require pyrimethamine + sulfadiazine. ✅ IgM+ or PCR confirms acute infection.

Answer 43

a rare autosomal dominant genodermatosis caused by mutations in the ATP2A2 gene, leading to abnormal keratinization. It presents with greasy, hyperkeratotic papules in seborrheic areas and nail changes. Clinical Features A. Cutaneous Manifestations Greasy, hyperkeratotic, yellow-brown papules/plaques in: Seborrheic areas (scalp, forehead, nasolabial folds, chest, back). Flexures (groin, axillae) → malodorous vegetating plaques. "Dirty" appearance due to scaling and crusting. Palmoplantar pits (50% of cases). B. Nail Changes Longitudinal red/white streaks. V-shaped notching at free edge. Subungual hyperkeratosis. C. Mucosal Involvement Cobblestone papules on palate, gums. Diagnosis A. Clinical Suspicion Family history (AD inheritance, 70% penetrance). Characteristic rash + nail findings. B. Histopathology (Gold Standard) Suprabasal acantholysis (epidermal separation). Dyskeratosis (abnormal keratinocyte apoptosis → corps ronds & grains). Differential Diagnosis Condition Key Differences Hailey-Hailey disease No dyskeratosis, affects flexures only. Grover’s disease No nail/mucosal involvement, transient. Seborrheic dermatitis Less hyperkeratotic, no acantholysis. Treatment A. Topical Therapy Emollients (urea 10–20%, lactic acid). Retinoids (tazarotene 0.1% gel). Antimicrobials (clindamycin 1% for superinfection). B. Systemic Therapy (Severe Cases) Oral retinoids (acitretin 10–25 mg/day) – best for widespread disease. Doxycycline (anti-inflammatory). C. Procedural Interventions Laser ablation (CO₂ for hypertrophic plaques). Botulinum toxin (reduces sweating-triggered flares). ✅ Greasy, hyperkeratotic plaques + nail streaks = Classic DD. ✅ Biopsy shows acantholysis & dyskeratosis. ✅ Oral retinoids (acitretin) are most effective systemic therapy. ✅ Avoid triggers (heat, friction, infections).

Answer 44

, a chronic form of cutaneous lupus, can cause permanent hair loss, also known as scarring alopecia, if the rash on the scalp progresses to scarring. The inflammatory process of DLE can damage hair follicles and lead to their destruction, resulting in permanent hair loss. Topical or Intralesional Corticosteroids

Answer 45

Cefixime chloramphenicol - grey baby syndrome Typhoid fever is a systemic bacterial infection caused by Salmonella enterica serotype Typhi (or Paratyphi A/B/C). It is transmitted via contaminated food/water and is endemic in areas with poor sanitation. Clinical Features A. Classic Presentation (1–3 Weeks After Exposure) Stepwise fever (rises daily, peaks at 39–40°C). Bradycardia relative to fever (Faget’s sign). Headache, malaise, anorexia. "Rose spots" (2–4 mm pink macules on trunk, fading on pressure). Hepatosplenomegaly. Constipation (early) → Diarrhea (late, "pea-soup stools"). B. Severe Complications System Complications GI Intestinal perforation, hemorrhage (3rd week). Neurologic Delirium, encephalopathy ("typhoid psychosis"). Cardiac Myocarditis, shock. Hematologic Disseminated intravascular coagulation (DIC). osteomialysis - sickle cell anemia 2. Diagnosis A. Laboratory Tests Blood Culture (1st week, 60–80% sensitivity). Stool Culture (2nd–3rd week). Bone Marrow Culture (95% sensitive, rarely needed). Serologic Tests (Widal Test) – Limited value (false +/- common). PCR (research settings). B. Imaging Abdominal X-ray: Free air if perforated. Ultrasound: Hepatosplenomegaly, mesenteric lymphadenopathy. C. Differential Diagnosis Malaria, dengue, TB, viral hepatitis. Other bacterial enteric fevers (e.g., Yersinia, Campylobacter). 3. Treatment (WHO & UK Guidelines) A. First-Line Antibiotics Drug Regimen Notes Ceftriaxone 50–75 mg/kg/day IV × 10–14 days 1st-line for severe cases. Azithromycin 10–20 mg/kg/day PO × 7 days 1st-line for uncomplicated cases. Ciprofloxacin 15 mg/kg/day PO × 7–10 days Avoid in high-resistance areas. B. Adjunctive Therapy IV fluids (dehydration, shock). Corticosteroids (severe encephalopathy/shock: dexamethasone 3 mg/kg IV). ✅ Stepwise fever + bradycardia + rose spots = Classic typhoid. ✅ Blood culture (1st week) or stool culture (2nd–3rd week) confirms. ✅ Ceftriaxone/azithromycin are 1st-line (avoid fluoroquinolones in resistance zones). ✅ Vaccinate travelers (TCV preferred).

Answer 46

within 72 hours of the onset of the rash severe

Answer 47

rare skin disorder characterized by fever and the sudden appearance of tender, red or purple lumps or patches on the skin. It's a reactive process where neutrophils, a type of white blood cell, gather in the skin, often in response to infection, cancer, or certain medications Tender, red or purple lumps (papules or nodules) or patches (plaques) that may become painful and even ulcerate. Systemic Symptoms: Other symptoms may include tiredness, joint pain, headaches, and mouth ulcers. Neutrophilic Dermatosis: The condition is classified as a neutrophilic dermatosis because neutrophils, a type of white blood cell, accumulate in the skin. Hypersensitivity Reaction: Sweet's syndrome is thought to be a hypersensitivity reaction by the immune system to a specific agent. causes - Infections of the respiratory or gastrointestinal, Malignancy, Autoimmune, pregnancy Corticosteroids oral

Answer 48

Respiratory Symptoms: Cough: A persistent cough, which may be dry initially but can progress to producing mucus or even blood. Shortness of Breath, Chest Pain, Pleuritic Chest Pain, relative bradicardia Systemic Symptoms: Fever: A high fever, often exceeding 104°F (40°C), is a common early symptom. Muscle Aches Headache: Headaches can be a prominent symptom, especially in the initial stages. Fatigue and Malaise Gastrointestinal Symptoms: Diarrhea, nausea, vomiting, and abdominal pain are frequently reported. Neurological Symptoms: Confusion, disorientation, and other mental changes can occur. Other Potential Manifestations: Skin Rash: In some cases, a rash may develop, with various presentations like maculopapular, indurated plaques, or hemorrhagic lesions. Renal Failure: In severe cases, kidney impairment can occur. invade and replicate within alveolar macrophages, hijacking the cells' defenses to proliferate gram negative

Answer 49

a sexually transmitted infection (STI) caused by the protozoan parasite Trichomonas vaginalis frothy, greenish or yellowish, and have a foul odor), vulval itching, and painful urination. or asymptomatic asymptomatic, but some may experience urethral discharge, painful urination, or testicular pain. Incubation Period: 3 to 28 days of infection metronidazole, taken for 5-7 days. examining a sample of vaginal or urethral fluid under a microscope or using a urine sample. More sensitive tests, like nucleic acid amplification tests (NAATs)

Answer 50

topical antibiotics oral tetracycline; 65% on erythromycin oral trimethoprine

Answer 51

an autoimmune disease where the body's immune system mistakenly attacks proteins in the basement membrane of the epidermis, leading to the formation of blisters. This occurs due to autoantibodies, specifically targeting BP180 and BP230 proteins, which are crucial for anchoring keratinocytes immunoglobulin G (IgG) autoantibodies bind to the skin basement membrane Nikolsky's sign: In bullous pemphigoid, the Nikolsky's sign is negative, which means the blisters don't easily slide away when touched Itching: This is a common early symptom and can precede the appearance of blisters by weeks or months. Rash: A red, itchy rash, sometimes resembling hives or eczema, may precede the blisters. Blisters: Large, tense, fluid-filled blisters are a hallmark of bullous pemphigoid. They often appear on the trunk, limbs, and flexures, says the Primary Care Dermatology Society. Mucosal Involvement:

Answer 52

Parvovirus B19, which causes erythema infectiosum (fifth disease), also replicates in bone marrow and can cause aplastic anemia, especially in individuals with underlying hemolytic anemia or immune disorders. In pregnant women, parvovirus B19 infection can lead to severe fetal anemia and, in rare cases, fetal death. lu-like illnesses, joint pain, and sometimes a rash. While the characteristic "slapped cheek" rash is more common in children, adults can also experience a rash, especially on the torso, arms, and legs. Joint pain, particularly in the hands, wrists, knees, and ankles, is a common symptom in adults. Joint Pain and Swelling: Arthralgia, or joint pain, and swelling are frequent symptoms Severe Illness: In rare cases, particularly in individuals with underlying conditions like sickle cell disease or weakened immune systems, parvovirus B19 can cause more severe complications like transient aplastic crisis (temporary cessation of red blood cell production) or anemia.

Answer 53

Hyperthyroidism: Graves' Disease: An autoimmune disorder where the immune system mistakenly attacks the thyroid gland. Toxic Multinodular Goiter: A condition where multiple nodules on the thyroid gland become overactive and produce excess hormone. Solitary Toxic Nodule: A single nodule on the thyroid gland that becomes overactive. Thyroiditis: Subacute Thyroiditis: A temporary inflammation of the thyroid gland. Postpartum Thyroiditis: Inflammation of the thyroid gland after childbirth. Silent Thyroiditis: A type of thyroiditis that doesn't cause pain or other inflammatory symptoms. onycholysis.

Answer 54

Anthrax is a zoonotic infection caused by Bacillus anthracis, a spore-forming, Gram-positive bacterium. It primarily affects livestock but can infect humans through contact with spores (cutaneous, inhalation, or ingestion). Cutaneous Anthrax (Most Common, 95% of Cases) Painless papule → ulcer → black eschar (necrotic center with edema). Regional lymphadenopathy, fever, malaise. Mortality: <1% with treatment, 20% untreated. B. Inhalational Anthrax (Most Deadly) Initial flu-like symptoms (fever, cough, fatigue). Rapid progression to severe respiratory distress, hemorrhagic mediastinitis, shock. Widened mediastinum on CXR/CT (classic finding). Mortality: >50% even with treatment. C. Gastrointestinal Anthrax (Rare) Severe abdominal pain, vomiting, bloody diarrhea. Oropharyngeal form: Neck swelling, dysphagia. Mortality: 25–60%. D. Injection Anthrax (Drug Users) Severe soft tissue infection (necrosis, edema). Linked to contaminated heroin. 2. Diagnosis A. Laboratory Tests Gram stain & culture (blood, skin lesions, CSF, sputum) – "Boxcar-shaped" Gram-positive rods. PCR (rapid detection of B. anthracis DNA). Immunohistochemistry (tissue biopsies). B. Imaging (Inhalational Anthrax) CXR/CT: Widened mediastinum (hemorrhagic lymphadenitis), pleural effusions. C. Differential Diagnosis Cutaneous: Spider bite, tularemia. Inhalational: Pneumonia, COVID-19, mediastinitis. Treatment (UK & WHO Guidelines) A. Cutaneous Anthrax (No Systemic Symptoms) Ciprofloxacin 500mg PO twice daily × 7–10 days (1st-line). OR Doxycycline 100mg PO twice daily × 7–10 days. B. Systemic/Inhalational/GI Anthrax IV Antibiotics: Ciprofloxacin 400mg IV every 12h + Clindamycin (toxin inhibition) or Penicillin G. Monoclonal Antibodies: Raxibacumab/Obiltoxaximab (neutralizes toxin). Supportive Care: ICU for shock/respiratory failure. C. Post-Exposure Prophylaxis (PEP) Ciprofloxacin 500mg PO twice daily × 60 days (or doxycycline). Anthrax vaccine (if available, 3-dose series). ✅ Cutaneous: Black eschar + edema (low mortality if treated). ✅ Inhalational: Widened mediastinum (high mortality). ✅ Treatment: Ciprofloxacin/doxycycline + antitoxin (if systemic). ✅ PEP: 60-day antibiotics + vaccine (for exposed individuals).

Answer 55

Cutaneous Leishmaniasis (CL): Lesions: Solitary or multiple skin sores, initially small red papules that ulcerate and may become crusted. Appearance: Ulcers are typically painless, but some may be moist and exude pus, while others dry with a crusted scab. Location: Lesions often appear on exposed skin, particularly on the face and extremities. Resolution: Most lesions resolve spontaneously, sometimes leaving residual scarring.

Answer 56

Mucocutaneous Leishmaniasis (MCL): L. braziliensis in Latin America, L. aethiopica in Africa/Asia) Lesions: Sores in the mucous membranes of the nose, mouth, or throat, often developing after the primary cutaneous lesion resolves. Symptoms: Sneezing, nosebleeds, and nasal or oral ulcers. Complications: Severe disfigurement and potential for respiratory or neurological complications. Post Kala-Azar Dermal Leishmaniasis (PKDL): Skin lesions: Develop after treatment for visceral leishmaniasis, characterized by hypopigmented or erythematous patches, papules, nodules, and plaques. Location: Lesions often appear on the face, upper body, and sometimes extremities. Geographic variations: The onset and duration of PKDL lesions vary depending on the region (e.g., Sudan vs. India). ✅ Suspect MCL in patients from endemic areas with chronic nasal/oral ulcers. ✅ PCR/biopsy confirms diagnosis (microscopy often negative). ✅ Liposomal amphotericin B is 1st-line (antimonials toxic but still used). ✅ HIV coinfection requires prolonged therapy & monitoring.✅ Suspect MCL in patients from endemic areas with chronic nasal/oral ulcers. ✅ PCR/biopsy confirms diagnosis (microscopy often negative). ✅ Liposomal amphotericin B is 1st-line (antimonials toxic but still used). ✅ HIV coinfection requires prolonged therapy & monitoring.

Answer 57

novanosis, is a sexually transmitted infection caused by the bacterium Klebsiella granulomatis. It's characterized by painless, progressive ulcers on the genitals or perineum, which can bleed easily and be accompanied by subcutaneous granulomas (pseudobuboes) Donovan bodies on microscopic examination, especially when stained with Giemsa or Wright's stain, is a key diagnostic sign for donovanosis. antibiotics, such as azithromycin, doxycycline, or erythromycin.

Answer 58

1. Early Neurosyphilis (Asymptomatic or Symptomatic) first few months to years after initial infection. Asymptomatic NeuroSyphilis: most common form. Symptomatic Meningeal Neurosyphilis: within the first year of infection. It resembles meningitis. Symptoms: Headache, neck stiffness, nausea, vomiting, sensitivity to light (photophobia), and sometimes changes in mental status. Cranial nerve palsies can cause vision or hearing problems. 2. Late Neurosyphilis - years to decades Meningovascular Neurosyphilis: This form involves inflammation of the brain's blood vessels, leading to strokes. Symptoms: Can mimic a typical stroke - Parenchymal Neurosyphilis: This involves direct damage to the brain cells (parenchyma). - General Paresis (also known as General Paralysis of the Insane): A severe, progressive dementia. Symptoms: Personality changes, irritability, confusion, poor judgment, memory loss, hallucinations, delusions (often of grandeur), and eventually seizures and loss of motor control. - Tubes Dorsalis: This affects the spinal cord, specifically the posterior columns that are responsible for vibration and position sense. Symptoms: Severe, stabbing "lightning" pains in the legs and abdomen, poor coordination (ataxia), unsteady gait (walking like you're on a ship), loss of bladder control, erectile dysfunction, and loss of reflexes. A key sign is Argyll Robertson pupils—pupils that constrict when focusing on a near object (accommodation) but do not react to light. - Ocular Syphilis and Otosyphilis: While sometimes considered separate, they are forms of neurosyphilis. Ocular Syphilis: Affects the eye, causing vision blurring, decreased vision, and permanent blindness. - Otosyphilis: Affects the inner ear, causing hearing loss, tinnitus (ringing in the ears), and dizziness. Diagnosis Clinical History and Symptoms Blood Tests: Non-treponemal tests: VDRL or RPR. These are used to screen for and monitor treatment. Treponemal tests: FTA-ABS or TP-PA. These confirm a current or past infection. Cerebrospinal Fluid (CSF) Analysis: This is the gold standard CSF-VDRL: A positive result is highly specific for neurosyphilis, but it can be negative in some cases. CSF Cell Count & Protein: An elevated white blood cell count and elevated protein level indicate inflammation in the CNS, which is consistent with neurosyphilis. CSF FTA-ABS: A negative result is very good at ruling out neurosyphilis. Treatment intravenous Penicillin G, administered for 10-14 days.

Answer 59

sensory ataxia (unsteady gait), lancinating pains, bladder dysfunction, and visual changes. Argyll Robertson pupil:, Charcot joints, Sensory ataxia, Lancinating pains, Paresthesias, Loss of coordination and reflexes,

Answer 60

bacteria roughly doubles every 24 hours nontuberculous mycobacterial (NTM) infections, are treated with a combination of antibiotics, and sometimes surgery. clarithromycin, azithromycin, rifampin, rifabutin, ethambutol, streptomycin, and amikacin. Radiological Findings: Atypical findings on chest X-rays or CT scans can include: Interstitial nodules Lower and middle lobe infiltrates Intrathoracic lymphadenopathy Pleural effusions Normal chest X-rays in some cases Nodular opacities, cavities, brochiectasis, and lymphadenopathy mimicking TB

Answer 61

Fever, headache, and fatigue in the initial stages. Later, if untreated, the disease can progress to neurological problems like sleep disturbances, confusion, and poor coordination. pentamidine, suramin, melarsoprol, eflornithine, nifurtimox, and the newer drug fexinidazole. The specific treatment depends on the stage of the disease (first or second) and the type of trypanosome involved (T. brucei gambiense or T. brucei rhodesiense

Answer 62

human herpesvirus type 6 (HHV-6) or, less commonly, human herpesvirus type 7 (HHV-7)

Answer 63

Disseminated disease: Disseminated MAC infection in HIV patients can affect multiple organs and systems, leading to fever, night sweats, weight loss, abdominal pain, and diarrhea, Anemia and elevated alkaline phosphatase levels are often seen, particularly in disseminated disease.

Answer 64

a paradoxical worsening of a pre-existing infection or the appearance of a new infection that occurs after starting antiretroviral therapy (ART) in people with HIV/AIDS. It's essentially a hyperinflammatory response fever, worsening of existing symptoms, new or worsening lung issues, or even neurological problems.

Answer 65

Classic Kaposi's Sarcoma: This is the most rare and least aggressive type, typically affecting older men of Mediterranean, Eastern European, or Ashkenazi Jewish heritage. It often manifests as slow-growing skin lesions on the lower extremities. Endemic Kaposi's Sarcoma: This type is more common in equatorial Africa, particularly in children and young adults. It can be aggressive and may involve internal organs. AIDS-related (Epidemic) Kaposi's Sarcoma: This is the most common type in the United States and is associated with HIV/AIDS. It can affect various organs and is often considered an AIDS-defining illness. Iatrogenic Kaposi's Sarcoma (Transplant-related): This type develops in people whose immune systems are suppressed after organ transplantation. It's caused by the reactivation of HHV-8 virus.

Answer 66

Primary Syphilis: Characterized by the appearance of one or more painless sores, called chancres, at the site of infection. These sores typically appear within 2-3 weeks of infection and may heal on their own within 3-6 weeks. Secondary Syphilis: Develops if primary syphilis is not treated and can manifest with a non-itchy rash, often on the palms of the hands and soles of the feet, fever, swollen lymph nodes, and other flu-like symptoms. Latent Syphilis: Occurs after the primary and secondary stages and can last for many years. During this stage, the infection is not always active, and the person may not experience any symptoms, Spirochaeta pallida, is a microaerophilic, gram-negative

Answer 67

a rare skin condition characterized by painful, rapidly growing ulcers, often with a purplish border. It's a neutrophilic dermatosis, meaning it involves an overabundance of neutrophils, a type of white blood cell. The condition is not contagious and is not related to gangrene. corticosteroids or calcineurin inhibitors like tacrolimus may be used for mild cases. Oral corticosteroids, such as prednisolone, are often the first line of treatment for more severe cases,

Answer 68

SONIC: S: ulfonamide allergy: Some protease inhibitors are chemically similar to sulfonamides, which can cause allergic reactions. O: rgan toxicity: Protease inhibitors can affect various organs, including the liver, kidneys, and heart, leading to toxicity. N: europathy: Peripheral neuropathy, or nerve damage, can occur as a side effect of protease inhibitors. I: nsulin resistance: These drugs can impair the body's ability to use insulin, leading to insulin resistance and potential hyperglycemia. C: reatine phosphokinase elevation: Elevated CK levels may indicate muscle damage, a side effect of some protease inhibitors.

Answer 69

Brain imaging (CT or MRI) typically shows ring-enhancing lesions, which are characteristic of cerebral toxoplasmosis. antiparasitic drugs, and in HIV-infected individuals, antiretroviral therapy is also crucial.

Answer 70

Hepatotoxicity: Anti-TB drugs, particularly isoniazid, rifampicin, and pyrazinamide, are associated with liver damage, ranging from mild to severe. Regular monitoring of liver function tests (ALT and AST) If liver damage is severe, the responsible drugs may need to be withdrawn and reintroduced gradually after liver function returns to normal.

Answer 71

Characterized by white, corrugated or shaggy patches on the tongue, primarily caused by Epstein-Barr virus (EBV) Hairy leukoplakia presents as white, non-removable patches on the tongue, often with a corrugated or shaggy appearance. In situ hybridization (ISH) can be used to confirm the diagnosis by detecting EBV DNA.

Answer 72

Initial Phase (Flu-like Illness): Fever, Fatigue, Headache, Muscle aches Nausea/Vomiting Second Phase (Neurological Symptoms): Stiff neck, Severe headache, photophobia, Confusion or disorientation, Seizures (fits), Weakness or loss of movement, Changes in behavior, slurred speech, Drowsiness or unresponsivenes

Answer 73

A bacterial infection transmitted by Ornithodoros (soft) ticks, leading to recurring episodes of fever and other symptoms. It's caused by spirochetes of the genus Borrelia, and while primarily found in Africa, Asia, and parts of the Americas, imported cases have been reported in Europe, including the UK. Diagnosis: Diagnosed through microscopic examination of blood samples. Treatment: Treated with antibiotics like doxycycline, usually for 7-10 days.

Answer 74

Key Features of PXE: Skin: Yellowish, waxy, cobblestone-like papules and loose folds, often appearing on the neck, armpits, and groin. Eyes: Angioid streaks (cracks in Bruch's membrane) and potential vision loss due to neovascularization. Vascular System: Premature atherosclerosis and potential for cardiovascular complications. Other: Gastrointestinal problems and musculoskeletal issues may also occur. autosomal recessive condition, ABCC6 gene muttion

Answer 75

a serious infection that involves inflammation and blood clots in the internal jugular vein, a major vein in the neck, often following a throat infection bacterium Fusobacterium necrophorum 1. Primary Oropharyngeal Infection: 2. Extension to Lateral Pharyngeal Space: The infection spreads from the primary site (tonsils, pharynx) to the lateral pharyngeal space formation of peritonsillar or retropharyngeal abscesses. 3. Septic Thrombophlebitis of the Internal Jugular Vein: thrombophlebitis). Extrinsic compression and vessel occlusion- thrombus formation. 4. Septic Embolization: septic emboli (clots containing bacteria) Travel to various organs and tissues, leading to metastatic infections. 5. Metastatic Infections: pneumonia, pleural empyema), joints, bones, muscles, liver, spleen, and other organs. Septic emboli can also lead to other complications like septic shock. prolonged course of intravenous antibiotics

Answer 76

characterized by facial redness, visible blood vessels, and sometimes papules and pustules Treatment of Rosacea: Topical Medications: Metronidazole, Azelaic acid, Brimonidine Ivermectin Oral Medications: Tetracyclines, Isotretinoin Lifestyle Changes: Avoid Triggers, Gentle Skin Care, Sun Protection

Answer 77

[](http://)pneumonia, bloodstream infections, urinary tract infections, and wound infections, often leading to serious complications like septicemia and septic shock. Pathological Features: Pneumonia: necrosis, inflammation, and hemorrhage. A thick, bloody, mucoid sputum, sometimes described as "currant jelly sputum," is characteristic. Bacteremia and Septicemia: bacteremia and, in more severe cases, septicemia and septic shock. Urinary Tract Infections (UTIs) Wound and Surgical Site Infections: wound and surgical site infections Liver Abscesses: K. pneumoniae is known to cause liver abscesses, a serious complication of infection. Meningitis and Endophthalmitis: meningitis or endophthalmitis Nosocomial Infections: ventilators or catheters. Factors Contributing to Klebsiella Infections: Impaired Host Defenses: weakened immune systems or underlying health conditions, such as alcoholism or diabetes Antibiotic Resistance: carbapenems, making treatment more challenging. A. Antibiotic Therapy Infection Type ##First-Line ##Alternatives (if resistant) Non-resistant UTI ##Ciprofloxacin/Trimethoprim ##Ceftriaxone, Nitrofurantoin (uncomplicated). ESBL-producing ##Meropenem/Ertapenem ##Ceftazidime-avibactam. Carbapenem-resistant (CRKP) ##Ceftazidime-avibactam ##Meropenem-vaborbactam, Polymyxins (last-line). Liver abscess ##Ceftriaxone + Drainage ##Carbapenems if ESBL suspected. ✅ "Currant jelly" sputum suggests Klebsiella pneumonia. ✅ Test for ESBL/carbapenemase in nosocomial infections. ✅ Ceftazidime-avibactam for CRKP; drain liver abscesses. ✅ hvKP strains cause community-acquired invasive disease.

Answer 78

caused by the Flavivirus, mosquito-borne viral disease primarily found in Africa and South America Mild symptoms: Fever, headache, muscle pain (especially backache), nausea, and vomiting. Severe symptoms: Jaundice, bleeding, and organ failure, which can be fatal. Symptoms typically appear 3-6 days after infection. ransmission & Epidemiology Vectors: Aedes (urban) and Haemagogus/Sabethes (sylvatic/jungle) mosquitoes. Endemic Regions: Africa: Sub-Saharan belt (Nigeria, DRC, Angola). South America: Amazon basin (Brazil, Peru, Colombia). High-Risk Groups: Unvaccinated travelers, forest workers. 2. Clinical Features A. Stages of Disease Acute Phase (3–6 days post-exposure): Sudden fever, chills, headache, myalgia. Faget’s sign: Bradycardia relative to fever. Conjunctival injection, facial flushing. Remission Phase (24–48 hours): Symptoms temporarily improve. 20–50% progress to toxic phase. Toxic Phase (15–25% of cases): Jaundice (liver damage → "yellow" fever). Hemorrhage: Melena, hematemesis ("black vomit"), epistaxis. No Specific Antiviral Therapy Supportive care: IV fluids (avoid overhydration in hemorrhage). Blood products (for severe bleeding). Dialysis (renal failure). B. Avoid Certain Medications NSAIDs (bleeding risk), aspirin, heparin. C. Intensive Care Vasopressors for shock. Mechanical ventilation if respiratory failure. Renal failure: Oliguria, proteinuria. Shock, multi-organ dysfunction. B. Mortality Case-fatality rate: 20–50% in toxic phase. 3. Diagnosis A. Laboratory Testing RT-PCR (blood, first 5 days of illness). Serology (IgM ELISA) (after day 5; cross-reacts with dengue/Zika). Liver function tests: Elevated AST/ALT (AST > ALT), bilirubin. CBC: Leukopenia, thrombocytopenia. ✅ Triphasic illness: Fever → remission → toxic phase (jaundice/hemorrhage). ✅ Diagnose with RT-PCR (early) or IgM (late). ✅ No cure – supportive care only (avoid NSAIDs/aspirin). ✅ Vaccine is highly effective (lifelong immunity).

Answer 79

a rare disorder where too many mast cells, a type of white blood cell, accumulate in the body, primarily in the skin, bone marrow, liver, spleen, and intestines.skin rashes, digestive issues, and potentially life-threatening allergic reactions. Diagnosis - bone marrow biopsies and blood tests to check for specific genetic mutations and elevated levels of mast cell mediators. Symptoms Symptoms vary based on the organs affected but commonly include: Skin: Flushing, itching, hives, and urticaria pigmentosa (brownish skin lesions) Gastrointestinal: Abdominal pain, diarrhea, nausea, vomiting, and peptic ulcers Systemic: Fatigue, bone/muscle pain, anemia, and osteoporosis Severe reactions: Anaphylaxis, hypotension, and organ damage (e.g., liver/spleen enlargement) Causes Most cases (80%) are caused by a somatic KIT gene mutation (often D816V), leading to uncontrolled mast cell growth and activation Triggers include alcohol, spicy foods, stress, insect stings, NSAIDs, and temperature changes Diagnosis Diagnosis follows WHO criteria, requiring either: Major criterion: Multifocal mast cell clusters (≥15 cells) in bone marrow or other organs Minor criteria: Elevated serum tryptase (>20 ng/mL), aberrant CD25/CD2 expression, KIT mutation, or atypical mast cell morphology Tests include bone marrow biopsy, blood tests (tryptase), and genetic testing Subtypes Indolent SM (most common): Mild symptoms, normal life expectancy. Smoldering SM: Higher mast cell burden but no organ dysfunction. Aggressive SM: Organ damage (e.g., bone fractures, cytopenias). SM with associated hematologic neoplasm (e.g., leukemia). Mast cell leukemia (rare, aggressive). Treatment Symptom control: Antihistamines (H1/H2 blockers) for itching/flushing/GI symptoms Leukotriene inhibitors (e.g., montelukast) for refractory symptoms Cromolyn sodium for GI and skin symptoms Epinephrine auto-injectors for anaphylaxis Advanced disease: Tyrosine kinase inhibitors (e.g., midostaurin) for KIT mutations Chemotherapy or bone marrow transplant for aggressive forms Prognosis Indolent SM: Near-normal life expectancy with management Aggressive subtypes: Poorer outcomes; survival ranges from months to years Key Recommendations Avoid triggers (e.g., alcohol, NSAIDs) Regular monitoring for bone density, blood counts, and organ function

Answer 80

Opportunistic CNS infection caused by Toxoplasma gondii (intracellular parasite). High-risk groups: HIV/AIDS (CD4 <100 cells/μL). Transplant recipients (post-solid organ/BMT). Congenital infection (rare). 2. Clinical Presentation Symptoms Subacute onset (days-weeks): Headache (70%), confusion, fever. Focal deficits (hemiparesis, seizures, aphasia). Altered mental status (if multiple lesions). Imaging (MRI > CT) Classic finding: Multiple ring-enhancing lesions (basal ganglia, corticomedullary junction). "Eccentric target sign": Nodular enhancement with eccentric dot (less specific). 3. Diagnosis 1. Neuroimaging + Clinical Context MRI brain with contrast: Multiple T2-hyperintense, ring-enhancing lesions. Differential: Lymphoma (PCNSL), TB, fungal abscess. 2. Serology (Limited in HIV) IgG+ (past exposure) ≠ active disease. IgM- (reactivation in HIV). 3. CSF PCR (Low Sensitivity, ~50%) T. gondii DNA detection (if lumbar puncture safe). 4. Brain Biopsy (Gold Standard, Rarely Needed) Indications: Atypical imaging, treatment failure. 5. Empirical Diagnosis (Common in HIV) CD4 <100 + MRI lesions + IgG+ → Treat empirically. Response to therapy (clinical/radiographic at 2 weeks) supports diagnosis. 4. Treatment First-Line (6 Weeks, Then Maintenance) Drug Dosing Notes Pyrimethamine 200 mg ×1, then 50–75 mg/day + Folinic acid (10–25 mg/day) to prevent bone marrow suppression. Sulfadiazine 1–1.5 g q6h Rash, crystalluria (hydrate!). Leucovorin (Folinic Acid) 10–25 mg/day Mandatory with pyrimethamine.

Answer 81

Pityriasis rosea (PR) is a self-limiting, inflammatory skin rash characterized by a distinctive "herald patch" followed by secondary erythematous lesions. It is most common in adolescents and young adults (ages 10–35) and typically resolves within 6–12 weeks. 1. Key Features Herald patch: A single, oval, scaly plaque (2–10 cm) appearing 1–2 weeks before the generalized rash. Secondary rash: Symmetrical, salmon-pink or red oval patches (smaller than the herald patch). "Christmas tree" distribution (lesions follow skin tension lines on the trunk). Mild itching (20–30% of cases). Prodromal symptoms (fatigue, headache, sore throat) in some patients. 2. Causes & Triggers Likely viral (associated with human herpesviruses 6/7 [HHV-6/7] reactivation). Not contagious, though clusters have been reported. More common in spring/fall. 3. Diagnosis Clinical Diagnosis (No Lab Tests Needed Typically) Herald patch + secondary rash are usually diagnostic. Dermoscopy: Shows peripheral scaling ("collarette scale"). Biopsy (rarely needed): Superficial perivascular lymphocytic infiltrate. if itchy/ serious - opical corticosteroids, antihistamines, or phototherapy Differential Diagnosis Tinea corporis (ringworm) – KOH test positive. Secondary syphilis – Check RPR/VDRL. Psoriasis guttata – More scaly, chronic. Eczema – More pruritic, no herald patch.

Answer 82

most common form of psoriasis, characterized by well-demarcated, erythematous plaques with silvery scales, typically affecting the scalp, elbows, knees, and lower back. Physical examination: Inspecting the skin, scalp, and nails for characteristic lesions History taking: Including age of onset, family history, triggers, and impact on quality of life Assessment tools: - Static Physician's Global Assessment (clear, nearly clear, mild, moderate, severe, or very severe) - Involvement of nails and difficult-to-treat sites (face, scalp, palms, soles, flexures, genitals) Treatment Recommendations Topical Therapy (First-line) Corticosteroids: Mild for sensitive areas (face, flexures) Vitamin D analogues: Calcipotriene and calcitriol to slow skin cell growth alone or combined with corticosteroids Combination products: Calcipotriol with betamethasone (e.g., Enstilar foam) -More effective Other options: Retinoids (tazarotene) Calcineurin inhibitors (for thin skin areas) Coal tar, salicylic acid, and anthralin Phototherapy (Second-line) - For moderate to severe psoriasis or when topical therapy fails Narrowband UVB: Preferred over broadband UVB PUVA: Psoralen + UVA for more severe cases Excimer laser: For localized plaques **Systemic Therapy (Moderate-to-severe)** When psoriasis is extensive (>10% BSA) or significantly impacts quality of life: 1. Conventional systemic drugs: Methotrexate Cyclosporine Acitretin 2. Biologics (targeted immunomodulators): TNF-α inhibitors (adalimumab, etanercept, infliximab) IL-12/23 inhibitors (ustekinumab) IL-17 inhibitors (secukinumab, ixekizumab, brodalumab) IL-23 inhibitors (guselkumab, tildrakizumab, risankizumab) 3. Small molecule drugs: Apremilast (PDE4 inhibitor) Deucravacitinib (TYK2 inhibitor) Special Considerations in Management Pediatric psoriasis: Requires specialist management; etanercept and ustekinumab are approved for children Pregnancy: Requires careful drug selection; some biologics are category B while acitretin and methotrexate are contraindicated Comorbidities: Screen for and manage psoriatic arthritis, cardiovascular disease, metabolic syndrome, and mental health issues Treatment failure: Consider switching biologics or combination therapies Emerging treatments like bimekizumab (dual IL-17A/F inhibitor) and roflumilast foam (PDE4 inhibitor)

Answer 83

Nail Psoriasis Treatment - Triamcinolone acetonide, Systemic Therapies - Methotrexate, Biologics, Small molecules Scalp Psoriasis- Roflumilast foam (PDE4 inhibitor) - Tapinarof cream (AhR modulator), Systemic Therapies

Answer 84

common form of panniculitis, an inflammatory condition affecting the subcutaneous fat layer. It presents as tender, red-to-purple nodules, typically on the shins, though it can also affect the thighs, arms, and other areas. Painful, warm nodules (1–10 cm in diameter) Bilateral and symmetric distribution (most commonly on shins) Self-limiting, usually resolving in 3–8 weeks Causes & Risk Factors 1. Infections (Most Common Identifiable Cause) Bacterial: Streptococcal pharyngitis, Tuberculosis Yersinia, Salmonella, Campylobacte Viral: Hepatitis B/C, HIV, COVID-19 Fungal: Coccidioidomycosis, histoplasmosis 2. Inflammatory & Autoimmune Conditions Sarcoidosis (Löfgren syndrome: EN + hilar lymphadenopathy + arthritis) Inflammatory bowel disease (Crohn’s, ulcerative colitis) Behçet’s disease HLA B27 3. Medications (3–10% of Cases) Antibiotics (sulfonamides, penicillin) Oral contraceptives NSAIDs (rare) 4. Other Causes Pregnancy (2nd trimester) Malignancies (lymphoma, leukemia) 68. Risk Factors Female predominance (3–6x more common in women, peak age 20–40) Management: NSAIDs, Potassium iodide, Colchicine

Answer 85

Keloids are fibroproliferative scars that extend beyond the original wound and do not regress spontaneously. They can cause pain, itching, and significant psychosocial distress, particularly in individuals with darker skin tones (Fitzpatrick types IV–VI) First-Line Treatments (Non-Surgical) - Intralesional Corticosteroid Injections (Triamcinolone Acetonide), Silicone Gel/Sheets, Pressure Therapy Second-Line & Adjunctive Therapies - Cryotherapy, 5-Fluorouracil (5-FU) Injections, Laser Therapy (Pulsed Dye Laser / CO₂ Laser),

Answer 86

1. Uncomplicated Malaria Fever (often >38.5°C) – Classically cyclical (every 48 hours), but irregular in non-immune individuals. Chills and rigors – Sudden onset, followed by sweating as fever breaks. Headache, myalgia, fatigue – Common flu-like symptoms. Nausea, vomiting, diarrhea – May mimic gastroenteritis. Mild jaundice – Due to hemolysis. Splenomegaly – Develops after repeated infections. 2. Severe Malaria (Medical Emergency) Severe malaria is defined by ≥1 of the following criteria (WHO 2023): A. Cerebral Malaria Impaired consciousness (GCS <11), seizures, or coma. Retinal hemorrhages (fundoscopy findings). Post-malaria neurological syndrome (rare, may occur after recovery). B. Severe Anemia Hemoglobin <5 g/dL (or <7 g/dL with parasitemia >10,000/µL). More common in children and pregnant women. C. Acute Kidney Injury (AKI) Oliguria/anuria, elevated creatinine. Caused by microvascular obstruction and hemolysis. D. Respiratory Distress & ARDS Metabolic acidosis (lactic acidosis) leads to rapid, deep breathing (Kussmaul respiration). Pulmonary edema may occur. E. Hypoglycemia Common in pregnant women and children. May be worsened by quinine treatment. F. Hemoglobinuria ("Blackwater Fever") Massive intravascular hemolysis → dark urine (hemoglobinuria). Associated with G6PD deficiency and certain antimalarials (e.g., primaquine). G. Coagulopathy & Bleeding Disseminated intravascular coagulation (DIC) may occur. Thrombocytopenia (common but rarely causes bleeding). H. Shock ("Algid Malaria") Hypotension, cold extremities, circulatory collapse. Often fatal if untreated. Complications of P. falciparum Malaria 1. Neurological Complications Seizures (especially in children). Long-term cognitive deficits (after cerebral malaria). Psychosis or ataxia (rare post-recovery). 2. Pregnancy-Related Complications Maternal anemia, stillbirth, low birth weight. Congenital malaria (rare but possible). 3. Relapse & Recrudescence Recrudescence: Recurrence due to incomplete treatment (within weeks). No true relapse (unlike P. vivax). 4. Secondary Infections Bacteremia (especially Salmonella in children). Aspiration pneumonia (in comatose patients). Key Takeaways Severe malaria is a medical emergency requiring IV artesunate. Cerebral malaria and acidosis are the most common causes of death. Children and pregnant women are at highest risk of complications. Misdiagnosis is common (can mimic sepsis, meningitis, hepatitis). Uncomplicated Malaria Artemisinin-based Combination Therapies (ACTs): First-line treatment (e.g., artemether-lumefantrine, dihydroartemisinin-piperaquine) Primaquine: Single low dose (0.25 mg/kg) Severe Malaria: Intravenous artesunate Parasite Factors Gametocyte carriage: Asymptomatic carriers (e.g., migrants in Thailand) sustain transmission. Risk factors include fever >7 days, anemia (Hb ≤8 g/dL), and ethnic minorities (e.g., Karen ethnicity) Drug-resistant strains: Linked to substandard treatments and incomplete regimens. PfEMP1 proteins facilitate sequestration, worsening organ damage

Answer 87

Zika virus is a flavivirus (related to dengue and yellow fever) transmitted primarily by Aedes mosquitoes (A. aegypti and A. albopictus). It gained global attention during the 2015–2016 epidemic due to its association with microcephaly and Guillain-Barré syndrome (GBS). Transmission Mosquito bites (main route). Vertical (mother-to-fetus): Causes congenital Zika syndrome. Sexual transmission (virus persists in semen for months). Blood transfusion/organ transplant (rare). Clinical Features A. Acute Infection (20% symptomatic) Incubation: 3–14 days. Symptoms: Mild fever, maculopapular rash (often pruritic). Arthralgia (small joints of hands/feet). Conjunctivitis (non-purulent). Myalgia, headache. Duration: Self-limiting (2–7 days). B. Complications Congenital Zika Syndrome (if infection during pregnancy): Microcephaly, brain calcifications. Retinal abnormalities, limb contractures. Guillain-Barré Syndrome (GBS): Ascending paralysis, areflexia (post-infection immune response). from endemic areas (e.g., Caribbean, Latin America, SE Asia) RT-PCR (viral RNA in blood/urine up to 2 weeks post-symptom onset). Serology (IgM) (cross-reactivity with other flaviviruses is a challenge). Amniocentesis (if fetal anomalies on ultrasound). No antiviral treatment (supportive care only). Acetaminophen (avoid NSAIDs until dengue ruled out). ✅ Most infections are mild/asymptomatic but can cause severe fetal harm. ✅ Test pregnant women with travel history to endemic zones. ✅ Avoid NSAIDs until dengue excluded (risk of bleeding). ✅ Prevent mosquito bites—critical in endemic regions.

Answer 88

Chikungunya is an alphavirus transmitted by Aedes mosquitoes (A. aegypti and A. albopictus), causing acute febrile illness and severe polyarthralgia. Clinical Manifestations A. Acute Phase (3–10 days post-exposure) High fever (≥39°C, abrupt onset). Severe polyarthralgia (bilateral, small joints—hands, wrists, ankles). Maculopapular rash (50% of cases, pruritic). Myalgia, headache, conjunctivitis. B. Subacute/Chronic Phase (Weeks to Months) Persistent arthritis (mimics rheumatoid arthritis). Fatigue, depression. Diagnosis A. Laboratory Tests RT-PCR (detects viral RNA in blood, useful in first 5–7 days). Serology (IgM/IgG ELISA) (after 5–7 days; cross-reactivity with other alphaviruses possible). Viral culture (research settings only). B. Differential Diagnosis Dengue (thrombocytopenia, hemorrhage). Zika (milder, rash + conjunctivitis). Rubella, parvovirus B19. Complications Chronic arthritis (up to 60% of patients, lasts months–years). Neurological: Encephalitis, Guillain-Barré syndrome (rare). Cardiac: Myocarditis, arrhythmias. Ocular: Uveitis, retinitis. Key Takeaways: ✅ Hallmark: Fever + severe symmetric joint pain. ✅ Diagnose early with RT-PCR or IgM ELISA. ✅ Chronic arthritis mimics rheumatoid disease. ✅ Avoid NSAIDs until dengue excluded.

Answer 89

Gonorrhoea is a sexually transmitted infection (STI) caused by Neisseria gonorrhoeae, a Gram-negative diplococcus. It primarily infects mucosal surfaces (genital, rectal, pharyngeal, conjunctival). Genital Infection Gender Symptoms Asymptomatic Rate Men Urethral discharge (purulent), dysuria, epididymitis, proctitis (MSM). 10–20% Women Cervicitis (purulent discharge), dysuria, intermenstrual bleeding. Up to 50% B. Extragenital Infection Pharyngeal: Sore throat (often asymptomatic). Rectal: Proctitis (pain, discharge, bleeding). Conjunctival: Purulent discharge (neonatal or adult). C. Disseminated Gonococcal Infection (DGI) Triad: Tenosynovitis, dermatitis (pustules), migratory arthritis. Rare but severe: Endocarditis, meningitis. A. Laboratory Testing NAAT (Nucleic Acid Amplification Test) First-line for urethral, cervical, rectal, pharyngeal swabs/urine. Note: Pharyngeal/rectal NAAT requires confirmation with culture if positive (due to false positives). Culture & Sensitivity Needed for antibiotic resistance testing (especially ceftriaxone/azithromycin). Samples: Urethral/cervical swab (Thayer-Martin medium). Microscopy (Gram Stain) Men with discharge: Intracellular Gram-negative diplococci (sensitivity >95%). Not reliable for women/pharyngeal/rectal samples. A. Uncomplicated Gonorrhoea First-line: Ceftriaxone 1g IM single dose (preferred). OR Cefixime 400mg PO single dose (if IM not feasible). Add Azithromycin 2g PO single dose (if resistance concerns, but avoid routine use due to resistance). B. Pharyngeal Gonorrhoea Ceftriaxone 1g IM (higher failure rate with oral cefixime). C. Disseminated Infection (DGI) Ceftriaxone 1g IV/IM daily for 7 days (+ azithromycin 1g PO if chlamydia co-infection suspected). D. Neonatal & Conjunctival Infection Ceftriaxone 25–50mg/kg IV/IM single dose. Complications Men: Epididymitis, prostatitis, urethral stricture. Women: PID, tubal infertility, ectopic pregnancy. Systemic: DGI, septic arthritis, endocarditis. Neonates: Ophthalmia neonatorum (blindness if untreated).

Answer 90

Scrub typhus is a zoonotic rickettsial infection caused by Orientia tsutsugamushi, transmitted by the bite of larval mites (chiggers). It is endemic in rural Asia-Pacific regions ("tsutsugamushi triangle"). Clinical Manifestations A. Classic Triad (5–14 days post-bite) Fever (high-grade, abrupt onset). Eschar (painless ulcer with black crust at bite site) – pathognomonic but absent in 30–50%. Maculopapular rash (trunk → limbs, spares palms/soles). B. Systemic Symptoms Headache, myalgia, lymphadenopathy. Severe cases: Pneumonia, meningoencephalitis, ARDS, DIC. Diagnosis A. Laboratory Tests Serology (Gold Standard) IFA (Indirect Immunofluorescence Assay) – Detects IgM/IgG (positive after 7–10 days). ELISA/ICT Rapid Tests (lower specificity). PCR (early infection, research settings). CBC/Chemistry – Leukopenia/thrombocytopenia, elevated LFTs. B. Differential Diagnosis Dengue/Leptospirosis (no eschar). Murine typhus (similar but urban, flea-borne). Malaria (no rash/eschar) First-Line Therapy Doxycycline 100mg PO/IV twice daily × 7 days (or 3 days afebrile). Alternatives: Azithromycin 500mg PO daily × 3–5 days (pregnancy/children). Chloramphenicol (if doxycycline unavailable). ✅ Endemic in Asia-Pacific – Travel history is crucial. ✅ Look for eschar (but absence doesn’t rule out disease). ✅ Doxycycline is first-line (even in children/pregnancy if severe). ✅ Delayed treatment → high mortality (up to 30%). Severe Cases IV doxycycline + ICU support (vasopressors if septic shock).

Answer 91

Pseudomembranous colitis is a severe inflammatory condition of the colon caused by toxin-producing Clostridioides difficile, often triggered by antibiotic use. It is characterized by yellow-white pseudomembranes on the colonic mucosa. A. Symptoms Watery diarrhea (often foul-smelling, may contain mucus/blood). Abdominal cramping/pain. Fever, leukocytosis (may mimic sepsis). Severe cases: Toxic megacolon, perforation, shock. B. Risk Factors Recent antibiotics (especially fluoroquinolones, clindamycin, cephalosporins). Hospitalization, advanced age, immunosuppression. PPI use (controversial, but may increase risk). A. Laboratory Tests Stool PCR (Detects C. difficile toxin genes tcdA/tcdB – most sensitive). Glutamate Dehydrogenase (GDH) + Toxin EIA (If PCR unavailable). Stool culture (Gold standard but slow; used for epidemiological studies). B. Endoscopy (Flexible Sigmoidoscopy/Colonoscopy) Pseudomembranes (yellow-white plaques on erythematous mucosa). Indicated if rapid diagnosis needed (e.g., ileus, suspicion of alternative diagnoses). C. Imaging (CT Abdomen) Colonic wall thickening, "accordion sign" (oral contrast trapped between pseudomembranes). Indicated if perforation/toxic megacolon suspected. A. Initial Episode, Non-Severe Fidaxomicin 200mg PO twice daily × 10 days (1st-line, lower recurrence risk). OR Vancomycin 125mg PO four times daily × 10 days. B. Severe/Fulminant Infection Vancomycin 500mg PO four times daily + IV Metronidazole 500mg every 8h. Consider rectal vancomycin enema if ileus present. Surgery consult (colectomy may be needed for toxic megacolon/perforation). C. First Recurrence Fidaxomicin or Vancomycin tapered/pulsed regimen. D. Multiple Recurrences (≥2 Episodes) Fecal Microbiota Transplant (FMT) (Highly effective). Bezlotoxumab (Monoclonal antibody against toxin B). Complications Toxic megacolon (abdominal distension, fever, hypotension). Colonic perforation, sepsis, death (if untreated). Chronic diarrhea, malnutrition. ✅ Diagnose with stool PCR (avoid testing if no diarrhea). ✅ Fidaxomicin/Vancomycin are 1st-line (metronidazole no longer preferred). ✅ FMT for recurrent CDI (>2 episodes). ✅ Toxic megacolon = Surgical emergency.

Answer 92

Hookworm infection: Caused by Necator americanus or Ancylostoma duodenale, leading to intestinal parasitosis (anemia, malnutrition). Cutaneous Larva Migrans (CLM): A zoonotic skin infection caused by animal hookworm larvae (e.g., Ancylostoma braziliense), leading to serpiginous, pruritic tracks. Clinical Features A. Hookworm Infection Early (Larval penetration): Itchy rash ("ground itch"). Chronic (Intestinal phase): Iron-deficiency anemia (fatigue, pallor, koilonychia). Protein loss (edema, stunting in children). Abdominal pain, diarrhea (less common). B. Cutaneous Larva Migrans (CLM) Erythematous, serpiginous tracks (1–2 cm/day) – "creeping eruption". Intense pruritus (worse at night). Secondary infection (from scratching). 3. Diagnosis A. Hookworm Infection Stool microscopy (Kato-Katz or concentration methods) – eggs visible. Complete blood count (CBC): Microcytic anemia, eosinophilia. Serum ferritin/iron studies (assess anemia severity). B. Cutaneous Larva Migrans (CLM) Clinical diagnosis (classic rash + exposure history). Skin biopsy (rarely needed; shows eosinophilic infiltrate). 4. Treatment A. Hookworm Infection Albendazole 400mg single dose (1st-line). Mebendazole 100mg twice daily × 3 days (alternative). Iron supplementation (if anemia present). B. Cutaneous Larva Migrans (CLM) Topical: Thiabendazole cream (applied to tracks for 5–7 days). Freezing with liquid nitrogen (for localized lesions). Oral (for severe/multiple lesions): Ivermectin 200 mcg/kg single dose (most effective). Albendazole 400mg daily × 3 days. 5. Key Takeaways ✅ Hookworm: Chronic anemia + eosinophilia → treat with albendazole + iron. ✅ CLM: Itchy, serpentine rash → ivermectin or topical thiabendazole. ✅ Stool O&P confirms hookworm; CLM is clinical

Answer 93

A soil-transmitted helminthiasis caused by Ascaris lumbricoides, the largest intestinal nematode (adults 15–35 cm). Endemic in tropical regions with poor sanitation. Ingestion of embryonated eggs (contaminated soil, food, water). Larvae hatch → migrate through lungs → coughed/swallowed → mature in small intestine. Clinical Manifestations A. Pulmonary Phase (Larval Migration) Löffler syndrome: Cough, wheezing, eosinophilic pneumonia (resolves in 1–2 weeks). B. Intestinal Phase (Adult Worms) Complication Symptoms Uncomplicated Asymptomatic, or mild abdominal pain, malnutrition (chronic infection). Intestinal obstruction Severe colicky pain, vomiting (worm bolus → emergency). Biliary ascariasis RUQ pain, jaundice (worms in bile ducts → cholangitis/pancreatitis). 3. Diagnosis A. Stool Microscopy Eggs (fertilized/unfertilized) on Kato-Katz thick smear (low worm burden may yield false negatives). B. Imaging Abdominal X-ray: "Worm masses" in obstruction. Ultrasound/CT: Adult worms in intestine/bile ducts (tubular filling defects). C. Eosinophilia Present during larval migration (may resolve in chronic infection). ✅ Pulmonary symptoms (Löffler syndrome) precede intestinal phase. ✅ Stool microscopy for eggs; imaging for complications. ✅ Albendazole single dose cures most cases. ✅ Surgery/ERCP for obstruction/biliary involvement.

Answer 94

**Cestodes (Tapeworms)** Taeniasis (Taenia saginata/solium) Clinical Features: Asymptomatic or mild abdominal pain. Complication: Cysticercosis (T. solium → neurocysticercosis). Treatment: Praziquantel (single dose). **Echinococcosis (Echinococcus granulosus)** Clinical Features: Hepatic cysts (RUQ mass), anaphylaxis if rupture. Treatment: Albendazole + PAIR (Puncture-Aspiration-Injection-Reaspiration). **Hookworm (Necator americanus, Ancylostoma duodenale)** Clinical Features: Iron-deficiency anemia, protein loss. Treatment: Albendazole/Mebendazole + Iron supplements. **Schistosomiasis** Clinical Features: Acute: Swimmer’s itch, Katayama fever (fever, eosinophilia). Chronic: Hepatic fibrosis, bladder cancer (S. haematobium). Treatment: Praziquant **Liver Flukes (Clonorchis/Opisthorchis)** Clinical Features: Biliary obstruction, cholangiocarcinoma. Treatment: Praziquantel. **A. Scabies (Sarcoptes scabiei)** Clinical Features: Intense nocturnal itching, burrows (finger webs, wrists). Treatment: Permethrin 5% cream or Ivermectin PO. **B. Pediculosis (Lice)** Clinical Features: Itching, nits on hair shafts. Treatment: Permethrin 1% lotion or Malathion.

Answer 95

Causative Agents: East Africa: Trypanosoma brucei rhodesiense (acute, severe). West/Central Africa: T. b. gambiense (chronic, progressive). Clinical Features: Stage 1 (Hemolymphatic): Fever, lymphadenopathy, rash. Stage 2 (CNS): Sleep disturbances, confusion, coma. Treatment: Stage 1: Pentamidine (gambiense), Suramin (rhodesiense). Stage 2: Melarsoprol (toxic) or Eflornithine + Nifurtimox (gambiense).

Answer 96

**Schistosomiasis (Bilharzia)** Species: S. haematobium (urinary), S. mansoni (intestinal). Clinical Features: Acute: Swimmer’s itch, Katayama fever (eosinophilia, fever). Chronic: Hematuria (haematobium), hepatic fibrosis (mansoni), bladder cancer. Treatment: Praziquantel (single dose). **Lymphatic Filariasis (Wuchereria bancrofti)** Transmission: Mosquito bite. Clinical Features: Acute: Fever, lymphangitis. Chronic: Lymphedema, hydrocele, elephantiasis. Treatment: Ivermectin + Albendazole (mass drug administration). **Onchocerciasis (River Blindness)** Transmission: Blackfly bite. Clinical Features: Skin: Intense itching, depigmentation ("leopard skin"). Eyes: Keratitis, blindness. Treatment: Ivermectin (kills microfilariae, not adult worms). **Whipworm (Trichuris)** Bloody diarrhea, rectal prolapse. Albendazole ✅ Malaria & schistosomiasis are leading causes of morbidity. ✅ Ivermectin is critical for filariasis and onchocerciasis control. ✅ Praziquantel cures schistosomiasis but does not prevent reinfection. ✅ Albendazole is first-line for soil-transmitted helminths (STH).

Answer 97

Nocardiosis is an opportunistic bacterial infection caused by Nocardia spp. (aerobic, filamentous, Gram-positive, weakly acid-fast bacteria). It primarily affects immunocompromised hosts, causing pulmonary, cutaneous, or disseminated disease. Pathogens: N. asteroides complex (most common), N. brasiliensis (cutaneous), N. farcinica (resistant strains). Transmission: Inhalation of soil/dust or direct inoculation through skin wounds. High-Risk Groups: Immunocompromised: HIV/AIDS (CD4 <100), transplant recipients, long-term steroids. Chronic lung disease (COPD, bronchiectasis). Healthy hosts (rare, usually cutaneous). Clinical Presentations A. Pulmonary Nocardiosis (Most Common) Symptoms: Fever, cough, dyspnea, hemoptysis (mimics TB/fungal pneumonia). Imaging: Cavitary lesions, nodules, pleural effusion. B. Cutaneous/Superficial Nocardiosis Lymphocutaneous (Sporotrichoid): Nodules with ascending lymphangitis. Mycetoma: Chronic granulomatous infection with sinus tracts (common in tropics). C. Disseminated Nocardiosis Brain abscess (50% of disseminated cases – headache, seizures, focal deficits). Other sites: Kidneys, bones, eyes. Diagnosis A. Microscopy & Culture Gram stain: Branching, beaded Gram-positive filaments. Modified acid-fast stain (weakly positive, distinguishes from Actinomyces). Culture: Slow-growing (2–14 days); notify lab if Nocardia is suspected. B. Molecular Methods 16S rRNA PCR (if culture-negative). MALDI-TOF MS (rapid identification). C. Imaging CT Chest: Cavitary/nodular lesions. MRI Brain: Ring-enhancing abscesses (if CNS involvement). First-Line Therapy Sulfonamides (TMP-SMX) – Drug of choice (15–20 mg/kg/day TMP component). Alternative: Amikacin + imipenem (severe/resistant cases). ✅ Think Nocardia in immunocompromised patients with cavitary pneumonia or brain abscesses. ✅ Gram stain shows branching filaments; weakly acid-fast. ✅ TMP-SMX is first-line (prolonged therapy needed). ✅ CNS involvement requires imaging + extended treatment.

Answer 98

PCP is a life-threatening fungal pneumonia caused by Pneumocystis jirovecii, primarily affecting immunocompromised patients (e.g., HIV/AIDS, transplant recipients). 1. Risk Groups HIV/AIDS (CD4 <200 cells/µL, especially if untreated). Transplant recipients (solid organ or hematopoietic stem cell). Patients on immunosuppressants (high-dose steroids, chemotherapy). Primary immunodeficiencies (e.g., SCID, hyper-IgM syndrome). Clinical Presentation A. Classic Triad (HIV Patients) Progressive dyspnea (weeks to months). Dry cough (non-productive). Fever (low-grade). B. Non-HIV Patients (More Acute & Severe) Rapid respiratory failure (days to weeks). Higher mortality due to delayed diagnosis. C. Physical Exam Findings Tachypnea, hypoxia (worse with exertion). Crackles (often absent despite severe disease). 3. Diagnosis A. Imaging Chest X-ray: Bilateral interstitial infiltrates (classic "ground-glass" appearance). Pneumothorax (in advanced cases). HRCT Chest: More sensitive; shows diffuse ground-glass opacities. B. Laboratory Tests Lactate Dehydrogenase (LDH): Elevated (non-specific). Arterial Blood Gas (ABG): Hypoxemia, increased A-a gradient. Beta-D-Glucan (BDG): Often elevated (supports fungal etiology). C. Definitive Diagnosis Sputum Induction/Bronchoalveolar Lavage (BAL): Microscopy (Giemsa, Grocott’s methenamine silver stain). PCR (high sensitivity, but may detect colonization). Biopsy (rarely needed; shows foamy alveolar exudates). First-Line Therapy TMP-SMX (Trimethoprim-Sulfamethoxazole): Dose: 15–20 mg/kg/day (TMP component) IV/PO in 3–4 divided doses. Duration: 21 days (HIV) or 14 days (non-HIV). Alternatives (if TMP-SMX contraindicated): Pentamidine IV (for severe cases, but toxic). Clindamycin + Primaquine (for mild-moderate cases). Atovaquone (for mild disease, PO only). ✅ Suspect PCP in immunocompromised patients with subacute dyspnea + dry cough. ✅ HRCT shows ground-glass opacities; LDH is often elevated. ✅ TMP-SMX is 1st-line therapy; add steroids if hypoxic. ✅ Prophylaxis is critical for high-risk patients.

Answer 99

A life-threatening fungal infection caused by Cryptococcus neoformans or C. gattii, primarily affecting immunocompromised patients (e.g., HIV/AIDS, transplant recipients). Classic Triad (Subacute Onset, Weeks to Months) Headache (progressive, often severe). Fever (low-grade). Altered mental status (confusion, lethargy, coma). B. Other Symptoms Nausea/vomiting (due to ↑ ICP). Neck stiffness (less pronounced than bacterial meningitis). Cranial nerve palsies (e.g., vision loss, hearing deficits). C. Elevated Intracranial Pressure (ICP) Papilledema (50% of cases). Risk of sudden death from brainstem herniation. 3. Diagnosis A. Lumbar Puncture (LP) & CSF Analysis Parameter Typical Findings Opening Pressure ##Often >25 cmH₂O (must be measured!). WBC Count## 10–500 cells/µL (lymphocytic predominance). Glucose ##Low (<40 mg/dL). Protein## Elevated (>100 mg/dL). India Ink Stain Sensitivity ##~70% (encapsulated yeast). Cryptococcal Ag (CrAg) ##>95% sensitivity/specificity (CSF/serum). B. Imaging MRI Brain: Gelatinous pseudocysts (basal ganglia), hydrocephalus. CT Head: Often normal; rule out mass lesions before LP. C. Serum Cryptococcal Antigen (CrAg) Screening in HIV patients (CD4 <100) to detect subclinical infection. 4. Treatment A. Induction Therapy (First 2 Weeks) Amphotericin B (Liposomal 3–4 mg/kg/day OR Deoxycholate 0.7–1 mg/kg/day) + Flucytosine (100 mg/kg/day in 4 divided doses) – Gold standard. Alternative if flucytosine unavailable: Fluconazole 800–1200 mg/day. B. Consolidation Therapy (Weeks 3–8) Fluconazole 400–800 mg/day PO. C. Maintenance Therapy (After Week 8) Fluconazole 200 mg/day PO until CD4 >100 (HIV) or immunosuppression resolved. D. Management of Elevated ICP Therapeutic LP (remove CSF to lower pressure; repeat if opening pressure >25 cmH₂O). Ventriculoperitoneal (VP) shunt if refractory. 5. Prognosis & Complications Mortality: 10–30% in HIV (higher without amphotericin). IRIS (Immune Reconstitution Inflammatory Syndrome): Worsening symptoms after ART initiation (delay ART by 4–6 weeks in HIV). Relapse: More common if adherence poor or fluconazole resistance. ✅ Suspect in HIV/AIDS with CD4 <100 + subacute headache. ✅ CSF CrAg is diagnostic; measure opening pressure (LP is critical!). ✅ Amphotericin B + flucytosine is 1st-line (fluconazole if unavailable). ✅ Aggressive ICP management (repeat LPs if needed).

Answer 100

Inflammation of the urethra caused by non-gonococcal pathogens, most commonly Chlamydia trachomatis (20–50%) and Mycoplasma genitalium (10–30%). athogen Prevalence Key Features Chlamydia trachomatis 20–50% Often asymptomatic; untreated → PID, infertility. Mycoplasma genitalium 10–30% Associated with treatment failure. Trichomonas vaginalis 2–10% Frothy discharge, pruritus. Ureaplasma urealyticum 5–20% Controversial pathogenicity. HSV (rare) <5% Painful ulcers, dysuria. Clinical Presentation A. Symptoms Urethral discharge (mucopurulent or clear). Dysuria (burning during urination). Itching/irritation at urethral meatus. Asymptomatic in up to 50% (Chlamydia). B. Physical Exam Urethral discharge (visible or expressible). Meatal erythema. 3. Diagnosis A. Laboratory Testing First-void urine (FVU) NAAT (PCR for Chlamydia, M. genitalium, Trichomonas). Urethral swab (Gram stain if NAAT unavailable): ≥5 WBCs per high-power field (confirms urethritis). No intracellular Gram-negative diplococci (rules out gonorrhea). B. Differential Diagnosis Gonococcal urethritis (more purulent discharge, Gram stain + for GN diplococci). Chemical/mechanical irritation (soaps, catheterization). 4. Treatment (CDC 2021 Guidelines) A. First-Line Therapy Doxycycline 100mg PO BID × 7 days (covers Chlamydia, some M. genitalium). Azithromycin 1g PO single dose (if poor adherence risk, but rising M. genitalium resistance). B. If Persistent Symptoms (Suspect M. genitalium) Moxifloxacin 400mg PO daily × 7–10 days (avoid if gonorrhea coinfection). C. Trichomonas Infection Metronidazole 2g PO single dose or Tinidazole 2g PO single dose. D. Partner Management Treat sexual partners empirically (same regimen) if exposed within 60 days. ✅ NAAT is gold standard (test for Chlamydia, M. genitalium, Trichomonas). ✅ Doxycycline × 7d is 1st-line (azithromycin if adherence concern). ✅ Moxifloxacin for treatment failures (suspect M. genitalium resistance). ✅ Test-of-cure not routine unless persistent symptoms.

Answer 101

Influenza A is a highly contagious respiratory viral infection caused by the influenza A virus (subtypes H1N1, H3N2). Typical Symptoms (Sudden Onset) Fever ≥38°C (often high-grade). Cough (usually dry). Sore throat, nasal congestion. Myalgia, headache, fatigue. Malaise, anorexia. B. Atypical Presentations Children: Vomiting, diarrhea, otitis media. Elderly/Immunocompromised: May present with confusion, sepsis-like illness without fever. C. Red Flags for Severe Disease Dyspnea, hypoxia (SpO₂ <92%). Hemodynamic instability (shock). Altered mental status, seizures. Secondary bacterial pneumonia (worsening cough, purulent sputum). Laboratory Confirmation (If Needed) RT-PCR (gold standard, used in hospitals). Rapid Antigen Tests (lower sensitivity, used in outbreaks). Nasopharyngeal/throat swab (best within 3–4 days of symptom onset). C. Who to Test? (UKHSA Guidance) Hospitalized patients with severe respiratory illness. Outbreaks in care homes/hospitals. Immunocompromised or high-risk patients. ntiviral Treatment Drug Dosing (Adults) Notes Oseltamivir 75mg PO BD × 5 days 1st-line for treatment. Zanamivir 10mg inhaled BD × 5 days Alternative if oseltamivir contraindicated. Who Gets Antivirals? ✅ High-risk groups (start within 48h of symptoms, or later if severe): Chronic respiratory disease (COPD, asthma). Cardiac, renal, liver disease. Diabetes, immunosuppression. Pregnancy, age ≥65 years. Morbid obesity (BMI ≥40) ✅ Sudden fever + cough + myalgia = Likely flu (clinical diagnosis often sufficient). ✅ Oseltamivir for high-risk patients within 48h (or later if severe). ✅ Test hospitalized/severe cases with PCR. ✅ Vaccinate high-risk groups annually.

Answer 102

JC Virus (JCPyV): A polyomavirus that latently infects kidneys/B-lymphocytes; reactivates under immunosuppression. High-Risk Groups: HIV/AIDS (CD4 <200 cells/µL). MS/autoimmune patients on natalizumab, rituximab, fingolimod. Transplant recipients (long-term immunosuppressants). Lymphoproliferative disorders (CLL, Hodgkin’s). 2. Clinical Features A. Classic Symptoms (Subacute Onset, Weeks-Months) Cognitive decline (memory loss, confusion). Motor deficits (weakness, ataxia). Visual disturbances (homonymous hemianopia, diplopia). Speech/language dysfunction (aphasia, dysarthria). B. Less Common Presentations Seizures (20% of cases). Cerebellar syndrome (gait imbalance). 3. Diagnosis A. MRI Brain (Gold Standard Imaging) T2/FLAIR: Multifocal white matter hyperintensities (subcortical, cerebellar, brainstem). No contrast enhancement (unless IRIS present). DWI: May show restricted diffusion at lesion edges. The MRI findings of cerebral white matter change without gadolinium enhancement are typical of progressive multifocal leukoencephalopathy (PML) B. CSF Analysis JCV DNA PCR (95% specific, but sensitivity ~70-90%). Mild lymphocytic pleocytosis (5–20 cells/µL). Elevated protein (50–100 mg/dL). C. Brain Biopsy (Rarely Needed) Demyelination + bizarre astrocytes with JC virus-positive nuclei (IHC). D. Differential Diagnosis MS flare, CNS lymphoma, HIV encephalopathy. 4. Management A. Immunosuppression Reduction HIV patients: Start ART immediately (may trigger IRIS). Natalizumab-associated PML: Plasmapheresis (remove drug) + immune reconstitution. Other immunosuppressants: Taper/discontinue if possible. ✅ Suspect PML in immunocompromised patients with subacute neurological decline. ✅ MRI shows asymmetric white matter lesions without mass effect. ✅ CSF JCV PCR confirms diagnosis (but false negatives occur). ✅ No cure – focus on immune recovery (stop immunosuppressants, start ART).

Answer 103

a foodborne zoonotic infection caused by Paragonimus trematodes (lung flukes), primarily affecting the lungs but capable of migrating to other organs. Transmission & Epidemiology Causative Species: P. westermani (Asia). P. mexicanus (Latin America). P. africanus (Africa). Reservoirs: Freshwater crabs/crayfish, wild boars. Endemic Regions: Asia: China, Korea, Philippines, Thailand. Africa: Nigeria, Cameroon. Americas: Ecuador, Peru. Infection Route: Ingestion of raw/undercooked crustaceans (crabs/crayfish) containing metacercariae. Larvae migrate from intestines → lungs (develop into adults in bronchioles). 2. Clinical Features A. Pulmonary Paragonimiasis (Most Common) Chronic cough (often with blood-tinged sputum). Hemoptysis (mimics TB or lung cancer). Chest pain, dyspnea. Eosinophilia (common but non-specific). B. Extrapulmonary Disease (20–40% of Cases) Site Symptoms CNS Headache, seizures, meningitis (cerebral paragonimiasis). Abdomen Abdominal pain, diarrhea (larval migration). Skin Subcutaneous nodules (migratory larvae). 3. Diagnosis A. Microscopy Sputum/stool exam: Detect oval, golden-brown eggs (60–80 µm). Bronchoscopy: Eggs in bronchoalveolar lavage (BAL). B. Serology ELISA for Paragonimus-specific antibodies (useful in extrapulmonary cases). C. Imaging Chest X-ray/CT: Nodules, cavities, pleural effusions. Ring-shaped/tunnel-like opacities ("worm migration tracks"). Brain MRI: "Soap bubble" lesions (cerebral paragonimiasis). D. Differential Diagnosis Tuberculosis (chronic hemoptysis, cavitary lesions). Lung cancer (nodules on imaging). Eosinophilic pneumonia (Löffler syndrome). First-Line Therapy Drug Dosing Notes Praziquantel 25 mg/kg PO TID × 2 days Drug of choice (95% cure rate). Triclabendazole 10 mg/kg PO single dose Alternative (especially for P. mexicanus). B. Adjunctive Therapy Corticosteroids (for cerebral paragonimiasis to reduce inflammation). ✅ Chronic hemoptysis + eosinophilia in endemic areas → suspect paragonimiasis. ✅ Eggs in sputum/stool confirm diagnosis; serology/imaging for extrapulmonary cases. ✅ Praziquantel × 2 days is curative (triclabendazole for resistant cases). ✅ CNS involvement requires steroids + antiparasitics.

Answer 104

Fitz-Hugh-Curtis syndrome is a complication of pelvic inflammatory disease (PID) characterized by perihepatitis (inflammation of the liver capsule) due to ascending genital tract infection. Causes & Pathogens Most Common: Chlamydia trachomatis (30–50%) and Neisseria gonorrhoeae. Less Common: Mycoplasma genitalium, other PID-related bacteria. 2. Clinical Features A. Classic Presentation Right upper quadrant (RUQ) pain (sharp, pleuritic, worse with movement). Fever, nausea, vomiting (mimics biliary disease). Concurrent PID symptoms: Lower abdominal pain. Cervical motion tenderness. Purulent vaginal discharge. B. Key Distinctions from Biliary Disease No jaundice or elevated bilirubin. Normal liver enzymes (ALT/AST usually normal or mildly elevated). 3. Diagnosis A. Clinical Suspicion Young, sexually active female with RUQ pain + PID symptoms. B. Laboratory Tests NAAT for Chlamydia & Gonorrhea (cervical/urethral swab or urine). CBC: Leukocytosis. Liver function tests (LFTs): Mild ALT/AST elevation (rarely >2× ULN). CRP/ESR: Elevated (non-specific). C. Imaging Transvaginal Ultrasound: Assess for tubo-ovarian abscess (TOA). CT/MRI Abdomen: Hepatic capsular enhancement ("violin string" adhesions between liver & diaphragm). Laparoscopy (Gold Standard): Direct visualization of "violin-string" adhesions (fibrous bands on liver surface). 4. Treatment (CDC & UK Guidelines) A. Antibiotic Therapy (Cover PID Pathogens) First-Line (Outpatient): Ceftriaxone 500mg IM single dose + Doxycycline 100mg PO BID × 14 days + Metronidazole 500mg PO BID × 14 days (for anaerobes). Inpatient (Severe Cases): IV Ceftriaxone + Doxycycline + Metronidazole → switch to oral after 24–48h improvement.

Answer 105

Key Distinctions TB: Chronic systemic symptoms (fever, weight loss). Positive AFB/GeneXpert. Granulomas on histopathology. Paragonimiasis: Hemoptysis + eosinophilia in endemic areas. Eggs in sputum/stool. Responds to praziquantel. Nocardiosis: Immunocompromised host (HIV, transplant). Brain abscess/skin involvement. Gram-positive branching rods, weakly acid-fast. When to Suspect Each? Think TB: Chronic cough + cavitary lung lesions + positive AFB. Think Paragonimiasis: Hemoptysis + eosinophilia + raw seafood history. Think Nocardiosis: Pneumonia + brain abscess in immunosuppression. Note: Co-infections (e.g., TB + paragonimiasis) can occur in endemic areas!

Answer 106

Q fever is a zoonotic disease caused by the intracellular bacterium Coxiella burnetii. It ranges from acute febrile illness to chronic endocarditis and is a notifiable disease in many countries due to bioterrorism potential. 2. Clinical Presentations A. Acute Q Fever (90% of Cases) Flu-like syndrome: High fever, headache, myalgia, fatigue. Pneumonia (atypical, dry cough). Granulomatous hepatitis (elevated ALT/AST, hepatomegaly). Rash (rare; unlike other rickettsial infections). B. Chronic Q Fever (1–5% of Cases) Endocarditis (culture-negative, affects prosthetic/aortic valves). Vascular infections (aneurysms, grafts). Osteomyelitis, chronic hepatitis. C. Post-Q Fever Fatigue Syndrome Persistent fatigue ≥6 months (similar to chronic fatigue syndrome). 3. Diagnosis A. Serology (Primary Tool) Test Acute Q Fever Chronic Q Fever Phase I IgG Low or negative High titer (≥1:800) Phase II IgG Elevated (≥1:128) Lower than Phase I Phase II IgM Positive (early infection) Usually negative B. PCR Useful in first 2 weeks (before antibodies develop). C. Imaging Echocardiography: Vegetations in endocarditis. PET-CT: Detects vascular infections. D. Differential Diagnosis Acute: Influenza, pneumonia, viral hepatitis. Chronic: Culture-negative endocarditis (e.g., Bartonella). 4. Treatment A. Acute Q Fever Doxycycline 100mg PO BID × 14 days (1st-line). Alternative: Fluoroquinolones (e.g., ciprofloxacin) or macrolides (if doxycycline contraindicated). B. Chronic Q Fever (Endocarditis/Vascular) Doxycycline 100mg PO BID + Hydroxychloroquine 200mg PO TID × 18–24 months. Hydroxychloroquine alkalinizes phagolysosomes, enhancing doxycycline efficacy. Serologic monitoring: Phase I IgG titers should decline by 50% every 6 months. ✅ Occupational exposure (farmers, vets) + flu-like illness → suspect Q fever. ✅ Phase II IgM/IgG for acute; Phase I IgG for chronic. ✅ Doxycycline is 1st-line; add hydroxychloroquine for chronic cases. ✅ Chronic Q fever = endocarditis until proven otherwise.

Answer 107

Clinical Features A. Symptoms (Subacute Onset, Weeks) Stage 1 (Early, Non-Specific): Fever, headache, malaise, personality changes. Stage 2 (Intermediate, Meningeal): Nuchal rigidity, vomiting, confusion. Cranial nerve palsies (CN VI, III, VII most common). Stage 3 (Late, Coma): Seizures, hemiparesis, stupor B. Key Signs Basal Meningitis: Hydrocephalus (obstructive 3rd/4th ventricle). Stroke (vasculitis of penetrating arteries → infarcts). 2. Diagnosis A. CSF Analysis (Lumbar Puncture) Parameter Typical Findings Opening Pressure ↑↑ (often >25 cm H₂O). WBC Count 50–500 cells/µL (lymphocytic). Glucose Low (<40 mg/dL or CSF:serum <0.5). Protein High (>100 mg/dL). AFB Smear Low sensitivity (<20%). PCR/Xpert MTB/RIF High specificity (85–95%). B. Imaging MRI Brain: Basal meningeal enhancement. Tuberculomas (ring-enhancing lesions). Infarcts (basal ganglia, thalamus). CT Head: Hydrocephalus, edema. C. Systemic TB Workup Chest X-ray (50% show active/old TB). Sputum AFB/GeneXpert (if pulmonary TB suspected). D. Differential Diagnosis Bacterial meningitis (acute, neutrophilic CSF). Cryptococcal meningitis (HIV+, India ink +). Neurosyphilis (+RPR/VDRL). 3. Treatment (WHO Guidelines) A. Antitubercular Therapy (ATT) Intensive Phase (2 Months): Rifampicin + Isoniazid + Pyrazinamide + Ethambutol (HRZE). Continuation Phase (7–10 Months): Rifampicin + Isoniazid (HR). B. Adjunctive Steroids Dexamethasone (0.4 mg/kg/day, taper over 6–8 weeks). Reduces mortality (especially in Stage 2/3). C. Management of Complications Hydrocephalus: Ventriculoperitoneal (VP) shunt if symptomatic. Stroke/Vasculitis: Aspirin (controversial, some use low dose). Seizures: Levetiracetam (avoid enzyme-inducing drugs like phenytoin). Neurologic sequelae (30–50% survivors): Cognitive deficits, hemiparesis, blindness. 5. Key Takeaways ✅ Subacute headache + cranial nerve palsy → Suspect TBM! ✅ CSF shows lymphocytic pleocytosis, low glucose, high protein. ✅ Start ATT + steroids immediately (do not wait for confirmation). ✅ Xpert MTB/RIF on CSF improves early diagnosis.

Answer 108

Key Diagnostic Clues Bacterial Meningitis: Cloudy CSF, neutrophilic pleocytosis, very low glucose. Examples: S. pneumoniae, N. meningitidis. Viral Meningitis: Lymphocytic pleocytosis, normal glucose, PCR+. Examples: Enterovirus, HSV-2. Tuberculous Meningitis (TBM): Lymphocytic, very high protein, low glucose. Xpert MTB/RIF or culture confirms. Cryptococcal Meningitis: India ink (+), CrAg (+), mild lymphocytosis. Common in HIV (CD4 <100). Neurosyphilis: VDRL/RPR (+) in CSF, lymphocytic pleocytosis. Exceptions & Pitfalls Early bacterial meningitis (<24h): May show lymphocytic predominance. Partially treated bacterial meningitis: Can mimic viral/TBM (check history!). HSV encephalitis: RBCs in CSF (hemorrhagic necrosis).

Answer 109

protozoan parasite Trypanosoma cruzi, is endemic in Latin America. It has acute and chronic phases, with chronic disease causing cardiac and gastrointestinal complications. A. Routes of Infection Vector-borne: Feces of triatomine bugs ("kissing bugs") enter mucous membranes/bite wounds. Congenital: Mother-to-child transmission (5–10% risk). Blood transfusion/organ transplant. Oral ingestion (contaminated food/juice). B. Endemic Regions Latin America (Mexico, Argentina, Brazil, Bolivia). Southern U.S. (Texas, California) due to migration and local vectors. 2. Clinical Features A. Acute Phase (Weeks–Months Post-Exposure) Local signs: Chagoma (swollen bite site). Romaña’s sign (unilateral periorbital edema if conjunctival entry). Systemic symptoms: Fever, malaise, hepatosplenomegaly, lymphadenopathy. Myocarditis (rare but severe). B. Chronic Phase (Years Later, 20–30% of Cases) Cardiac (Chagas Cardiomyopathy): Arrhythmias (RBBB, VT, heart block). Dilated cardiomyopathy → heart failure. Thromboembolism (apical aneurysms, strokes). Gastrointestinal (Megaesophagus/Megacolon): Dysphagia, regurgitation, constipation, fecaloma. C. Reactivation in Immunocompromised (HIV, Transplant) Severe myocarditis, meningoencephalitis. 3. Diagnosis A. Acute Phase Microscopy: Trypomastigotes in blood (Giemsa stain). PCR: Highly sensitive (detects T. cruzi DNA). B. Chronic Phase Serology (Gold Standard): ELISA, IFA, or Western blot (≥2 tests for confirmation). ECG/Echo: RBBB, apical aneurysm, reduced LVEF. Barium Studies: Megacolon/megaesophagus. C. Congenital Screening PCR at birth, serology at 9–12 months. D. Differential Diagnosis Acute: Malaria, viral myocarditis. Chronic: Idiopathic cardiomyopathy, achalasia. 4. Treatment A. Antiparasitic Drugs Drug Indication Regimen Benznidazole 1st-line for acute/congenital 5–7 mg/kg/day PO × 60 days. Nifurtimox Alternative (higher toxicity) 8–10 mg/kg/day PO × 90 days. Notes: Chronic phase: Benefits uncertain (may slow progression). Contraindications: Pregnancy, severe hepatic/renal disease. B. Chronic Complications Cardiac: Amiodarone (for VT), pacemaker/ICD (heart block). Anticoagulation (if apical aneurysm). ✅ Acute: Romaña’s sign, fever, parasitemia (PCR/microscopy). ✅ Chronic: Cardiomyopathy (RBBB, apical aneurysm), megaesophagus. ✅ Treat acute/congenital cases with benznidazole (chronic benefit debated) GI: Pneumatic dilation/Botox (megaesophagus). Surgery (megacolon). C. Monitoring Annual ECG/Echo in chronic carriers.

Answer 110

A. ESBL-Producing K. pneumoniae & E. coli First-Line (Non-Severe Infections) Oral Options: Nitrofurantoin (for uncomplicated UTIs). Fosfomycin (single-dose for cystitis). Pivmecillinam (for UTIs). Severe Infections (Sepsis, Pyelonephritis) IV Carbapenems: Meropenem (1g IV TDS) – preferred. Ertapenem (1g IV OD) – if Pseudomonas not suspected. Alternatives (If Carbapenem-Sparing Needed) Ceftazidime-avibactam (if ESBL confirmed). Temocillin (for UTIs). B. Carbapenem-Resistant K. pneumoniae (CRKP) & E. coli First-Line (PHE Recommended) Ceftazidime-avibactam (2.5g IV TDS) – for *KPC/OXA-48-like* producers. Meropenem-vaborbactam (4g IV TDS) – KPC-only. For NDM/Metallo-β-Lactamase Producers Aztreonam + Ceftazidime-avibactam (aztreonam bypasses MBL resistance). Colistin (loading dose 9MU IV, then 4.5MU BD) + High-dose meropenem (2g IV TDS). Last-Resort Options Cefiderocol (2g IV TDS) – for multi-resistant strains. Tigecycline (100mg IV stat, then 50mg BD) – for non-UTI infections (low urinary penetration). C. AmpC-Producing E. coli & K. pneumoniae Avoid: 3rd-gen cephalosporins (e.g., ceftriaxone). Preferred: Carbapenems (meropenem). Cefepime (2g IV TDS) – stable against AmpC. 3. Special Considerations UTIs ESBL UTIs: Nitrofurantoin/fosfomycin (if sensitive). CRKP UTIs: Plazomicin (15mg/kg IV OD) – if available. CNS Infections CRKP meningitis: Meropenem (high-dose) + Fosfomycin (intrathecal if needed). Pediatric Dosing Ceftazidime-avibactam: 50mg/kg (max 2.5g) IV TDS. 4. Infection Control (UK Standards) Isolation: Contact precautions for resistant strains. Screening: Rectal swabs for CPO (Carbapenemase-Producing Organisms) in high-risk patients. Antibiotic Stewardship: Restrict carbapenems/colistin. 5. Key Takeaways ✅ ESBL infections: Carbapenems (meropenem) remain 1st-line for severe cases. ✅ CRKP: Ceftazidime-avibactam for KPC, aztreonam+CAZ-AVI for NDM. ✅ AmpC producers: Avoid ceftriaxone; use cefepime or carbapenems. ✅ UTIs: Nitrofurantoin/fosfomycin for ESBL; reserve carbapenems for pyelonephritis.

Answer 111

Abacavir Hypersensitivity Reaction (ABC HSR) Symptoms (usually within first 6 weeks of treatment): Fever, rash (often maculopapular) Gastrointestinal (nausea, vomiting, diarrhea) Respiratory (cough, dyspnea, pharyngitis) Systemic (fatigue, malaise, myalgia) Severe cases can lead to hypotension, liver toxicity, or even fatal reactions. Mechanism: Immune-mediated (not IgE-dependent). 2. Other ARVs Linked to HLA-B*57:01 (Less Common) Flucloxacillin (not an ARV but an antibiotic) – associated with hepatotoxicity. Some reports suggest possible (but rare) associations with nevirapine (an NNRTI), though HLA-B*35:05 and HLA-Cw4 are more commonly linked. 3. Testing & Management Screening: HLA-B*57:01 testing is mandatory before starting abacavir (per FDA & guidelines). If positive, abacavir is contraindicated (use alternative NRTIs like tenofovir/emtricitabine). If reaction occurs: Immediately discontinue abacavir (rechallenge can be fatal). Switch to another ARV regimen (e.g., TDF/FTC + dolutegravir). 4. Alternative ART Options NRTI alternatives: Tenofovir (TAF or TDF) + emtricitabine (FTC) or lamivudine (3TC). INSTIs (e.g., dolutegravir, bictegravir, raltegravir) are safe. NNRTIs (e.g., rilpivirine, doravirine) – no known HLA-B*57:01 link. Protease inhibitors (e.g., darunavir) – also safe. 5. Key Takeaway HLA-B*57:01-positive patients should NEVER receive abacavir (lifelong contraindication). Hypersensitivity is dose-independent and can recur fatally upon re-exposure. Always check for HLA-B*57:01 before prescribing abacavir-containing regimens (e.g., Triumeq, Ziagen).

Answer 112

A. Yersinia enterocolitica Gastroenteritis (most common): Watery or bloody diarrhoea Abdominal pain (often RLQ, mimicking appendicitis – "pseudoappendicitis") Fever, vomiting Symptoms last 1–3 weeks (can be prolonged in immunocompromised patients). Complications: Post-infectious reactive arthritis (especially HLA-B27-positive patients) Erythema nodosum (more common in women) Sepsis (rare, in immunocompromised patients) B. Yersinia pseudotuberculosis Similar to Y. enterocolitica but may also cause: Mesenteric adenitis (mimics appendicitis) Kawasaki-like syndrome (rare, in children) Yersinia pestis is the causative agent of plague, a severe and potentially fatal zoonotic infection. While rare in the UK, cases may occur in travellers from endemic regions (Africa, Asia, Americas). A. Bubonic Plague (Most Common, ~80-90% of Cases) Transmission: Flea bite or contact with infected animals. Incubation: 2–6 days. Symptoms: Sudden fever, chills, headache, myalgia Buboes (painful, swollen lymph nodes, usually inguinal/axillary) May progress to septicaemia if untreated. B. Septicaemic Plague Can occur primarily or secondary to bubonic/pneumonic plague. Symptoms: High fever, hypotension, DIC, multiorgan failure No buboes (making diagnosis harder). Mortality: Very high (~50-100%) if untreated. C. Pneumonic Plague (Most Severe & Contagious Form) Transmission: Inhalation of respiratory droplets (human-to-human spread possible). Incubation: 1–3 days. Symptoms: Severe pneumonia (dyspnoea, haemoptysis, chest pain) Rapid progression to respiratory failure & shock. Mortality: ~100% if untreated within 24h. 2. Diagnosis (UKHSA Guidelines) High suspicion needed (travel history to endemic areas). Sample collection: Buboes: Aspiration for Gram stain/culture/PCR. Blood cultures (for septicaemic plague). Sputum/BAL (for pneumonic plague). Rapid tests: PCR (gold standard, available at UKHSA Rare & Imported Pathogens Laboratory). F1 antigen detection (lateral flow test). Serology (for retrospective diagnosis). 3. Treatment (UKHSA & WHO Recommendations) A. First-line Antibiotics Gentamicin (5 mg/kg IV OD) – preferred in UK. Doxycycline (100 mg IV/PO BD) – alternative. Ciprofloxacin (400 mg IV BD or 500–750 mg PO BD). B. Severe/Pneumonic Plague Dual therapy (initially IV): Gentamicin + Doxycycline Ciprofloxacin + Doxycycline Duration: 10–14 days (or until clinical improvement). C. Post-exposure Prophylaxis (PEP) For close contacts of pneumonic plague cases: Doxycycline (100 mg PO BD × 7 days) Ciprofloxacin (500 mg PO BD × 7 days). 4. Complications & Management Septic shock: ICU care, fluids, vasopressors. DIC: Blood products as needed. Respiratory failure: Mechanical ventilation.

Answer 113

Vaccinations (Critical Before & After Splenectomy) A. Pre-Splenectomy (If Elective) Ideally given ≥2 weeks before surgery for optimal immune response. If emergency splenectomy, vaccinate ≥14 days post-op. B. Required Vaccines Vaccine Schedule Revaccination Pneumococcal (PCV13 + PPSV23) - PCV13 first. - PPSV23 8 weeks later. PPSV23 every 5 years. Meningococcal (MenACWY) Single dose. Booster every 5 years (if high risk). Haemophilus influenzae type b (Hib) Single dose (if not previously vaccinated). Not routinely repeated. Influenza (annual) Yearly flu vaccine. Every year. C. Additional Vaccines COVID-19: Follow UKHSA guidelines (boosters as recommended). Travel vaccines: Meningococcal B (Bexsero), typhoid, etc. 2. Antibiotic Prophylaxis A. Lifelong Prophylaxis (PHE & BCSH Recommendations) First-line: Phenoxymethylpenicillin (Penicillin V) 250mg BD (oral). If penicillin-allergic: Erythromycin 250mg BD or clarithromycin 250mg OD. B. High-Risk Situations Requiring Broader Coverage Travel to high-risk areas: Consider ciprofloxacin 500mg OD (for Gram-negative coverage). Dental procedures: Amoxicillin 3g PO 1h pre-op (if not on daily prophylaxis). C. Emergency Standby Antibiotics All splenectomy patients should carry: Amoxicillin 500mg–1g TDS (or clarithromycin if allergic). Seek immediate medical help if fever ≥38°C (even if taking antibiotics). 3. Patient Education (Key for Prevention) A. "Spleen Alert" Card & Medical ID Carry a splenectomy alert card (available from PHE/UK Splenectomy Registry). Wear a MedicAlert bracelet. B. Early Sepsis Recognition & Action Symptoms requiring urgent medical attention: Fever ≥38°C, rigors, malaise. Severe headache, vomiting, confusion. Action: Take emergency antibiotics immediately. Go to A&E (even if symptoms seem mild). C. Travel Advice Malaria prophylaxis (if traveling to endemic areas). Avoid tick bites (risk of Babesia/Capnocytophaga). ✅ Vaccinate pre-splenectomy if possible (PCV13 → PPSV23 + MenACWY + Hib). ✅ Lifelong penicillin V 250mg BD (or macrolide if allergic). ✅ Emergency antibiotics + immediate A&E for fever.

Answer 114

Key principles: Treat TB first (if CD4 >50), then start ART. Monitor for IRIS (worsening TB symptoms after ART initiation). Adjust ART if needed (due to rifampicin interactions). 2. TB Treatment Regimens (UK Standard) A. Drug-Susceptible TB 2HRZE (2 months) + 4HR (4 months) = 6 months total. Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), Ethambutol (E). B. Drug-Resistant TB Individualized regimens (e.g., bedaquiline, linezolid, fluoroquinolones). Directly Observed Therapy (DOT) recommended. 3. ART Considerations with TB Treatment A. When to Start ART? CD4 Count Recommended ART Start Time CD4 <50 Start ART within 2 weeks of TB Rx. CD4 ≥50 Start ART within 8 weeks of TB Rx. B. Rifampicin & ART Interactions Rifampicin reduces levels of some ARVs: Avoid protease inhibitors (PIs) unless boosted (e.g., ritonavir/darunavir). Preferred ART with rifampicin: NNRTIs (efavirenz 600mg OD) – 1st-line. Dolutegravir (DTG) 50mg BD (instead of OD due to rifampicin effect). Raltegravir 400mg BD (alternative). C. Alternative if Rifampicin Cannot Be Used Rifabutin (less interaction with ART) + adjust ART accordingly. 4. Managing TB-IRIS (Immune Reconstitution Inflammatory Syndrome) Occurs in 10–30% of co-infected patients (usually within 2–8 weeks of ART). Symptoms: Worsening fever, lymphadenopathy, pulmonary infiltrates. Management: Continue ART & TB treatment. Prednisolone 1 mg/kg/day (4 weeks, then taper) if severe. 5. Key Takeaways for UK Practice ✅ Treat TB first, then ART (timing depends on CD4). ✅ Avoid PIs with rifampicin (use efavirenz, dolutegravir, or raltegravir). ✅ Double dolutegravir dose (50mg BD) if on rifampicin. ✅ Monitor for IRIS (steroids if severe).

Answer 115

ey Definitions (Sepsis-3 Criteria) Sepsis: Life-threatening organ dysfunction caused by a dysregulated host response to infection. Septic shock: Sepsis with persistent hypotension requiring vasopressors AND lactate >2 mmol/L despite fluid resuscitation. Emergency Department Recognition Screening Tools qSOFA (Quick SOFA) - Bedside screening: Respiratory rate ≥22 Altered mentation (GCS <15) SBP ≤100 mmHg (≥2 points suggests high risk for poor outcomes) NEWS2 (National Early Warning Score 2) - UK standard: Assesses RR, SpO₂, BP, HR, temperature, consciousness. High-Risk Clinical Features ✔ Fever or hypothermia ✔ Tachycardia (HR >90) ✔ Tachypnea (RR >20) ✔ Hypotension (SBP <90 or MAP <65) ✔ Altered mental status ✔ Lactate ≥2 mmol/L (indicates tissue hypoperfusion) Immediate Management (Hour-1 Bundle) 1. Time-Zero Actions (First Hour) Oxygen (target SpO₂ 94-98%) Blood cultures (before antibiotics if possible) Broad-spectrum antibiotics (within 1 hour) Fluid resuscitation (30 mL/kg crystalloid bolus) Lactate measurement (repeat if initial >2) 2. Antibiotic Choices (Empirical) Suspected Source First-Line Antibiotics Community-acquired pneumonia Amoxicillin + Clarithromycin (or Doxycycline) Intra-abdominal Co-amoxiclav + Metronidazole (or Piperacillin-Tazobactam) UTI/Pyelonephritis Ceftriaxone (or Ciprofloxacin if penicillin allergy) Skin/Soft Tissue Flucloxacillin + Benzylpenicillin (or Clindamycin) Meningitis Ceftriaxone + Dexamethasone + Ampicillin (if >50yrs) 3. Vasopressor Initiation (If Shock) Norepinephrine (1st-line) Add vasopressin if refractory Consider hydrocortisone (if steroid-dependent or refractory shock) Investigations Labs: FBC, U&Es, CRP, LFTs, coagulation, blood gas Imaging: CXR, US/CT based on suspected source Point-of-care US (POCUS): Assess cardiac function, IVC collapsibility

Answer 116

Key Features in the ED High fever (>40°C) 3 C's: Cough, Coryza (runny nose), Conjunctivitis Koplik spots (white lesions on buccal mucosa) - pathognomonic but often missed Maculopapular rash (starts at hairline → spreads downward) Critical Red Flags ❗ Respiratory distress (pneumonia complication) ❗ Altered mental status (encephalitis) ❗ Severe dehydration (inability to tolerate fluids) ❗ Immunocompromised patients (at risk for fatal complications) Atypical Presentations Absence of rash (30–50% of cases) due to deficient cellular immunity Prolonged shedding of measles virus (weeks to months) Fulminant disease: Rapid progression to respiratory failure or encephalitis

Answer 117

topic Eczema Atopic eczema is diagnosed if a child has an itchy skin condition plus 3 or more of the following: Visible flexural dermatitis (e.g., elbows, knees) or facial/extensor involvement in infants (<18 months) History of dry skin in the past 12 months Personal/family history of atopy (asthma, allergic rhinitis) Onset before age 2 (not used for children <4 years)# Stepped Management Approach Treatment is tailored to severity and stepped up/down as needed: Step 1: Mild Eczema Emollients (mainstay of therapy, used daily even when skin is clear) Mild-potency topical corticosteroids (e.g., hydrocortisone 1%) Step 2: Moderate Eczema Moderate-potency topical corticosteroids (e.g., clobetasone butyrate) Topical calcineurin inhibitors (e.g., tacrolimus, pimecrolimus) for sensitive areas (face, neck) Bandaging techniques (wet wraps for severe flares) Step 3: Severe Eczema Potent topical corticosteroids (short-term use, avoid long-term without specialist input) Phototherapy (under specialist care) Systemic therapy (e.g., dupilumab, immunosuppressants) in refractory cases 4. Key Treatment Recommendations Emollients Prescribe large quantities (250–500 g per week) Avoid perfumed products; offer a choice of formulations (creams, ointments) Apply after bathing, smoothing onto skin (not rubbing) MHRA warning: Emollient residue on clothing/bedding poses a fire hazard Topical Corticosteroids Tailor potency to severity (mild for face, moderate/potent for body flares) Apply once daily (or twice if needed) Continue for 48 hours after flare resolution Infection Management Suspect infection if eczema worsens, oozes, or crusts. Swab before antibiotics; use oral flucloxacillin (or clarithromycin if penicillin-allergic) Eczema herpeticum (HSV infection) requires urgent oral/IV acyclovir

Answer 118

Presentation Appearance: Starts as a small, pimple-like lesion that rapidly grows into a volcano-shaped nodule (1–3 cm) with a central keratin plug Growth Phases: Proliferative phase (weeks 1–6): Rapid enlargement. Stabilization phase (weeks 6–12): Lesion remains unchanged. Regression phase (months 2–12): May shrink and heal, leaving a scar Common Locations: Face, hands, arms, and legs (especially in women) Variants Solitary KA (most common) Giant KA (>2 cm, often on eyelids/nose). Keratoacanthoma centrifugum marginatum (expands peripherally, rarely regresses). Multiple KA syndromes (e.g., Ferguson-Smith, Grzybowski) – rare, genetic forms with eruptive lesions 25. Causes and Risk Factors Sun exposure (UV radiation) – primary risk factor Immunosuppression (e.g., organ transplant recipients). Chemical carcinogens (tar, tobacco, industrial oils). HPV infection. Genetic predisposition (e.g., Muir-Torre syndrome) Diagnosis Clinical vs. Histological Diagnosis Biopsy is essential to differentiate KA from SCC. Histopathology: Shows a crateriform architecture with well-differentiated keratinocytes and a central keratin plug Dermoscopy is unreliable for distinguishing KA from SCC Differential Diagnosis Squamous cell carcinoma (SCC) – most critical distinction. Cutaneous horn. Actinic keratosis. Molluscum contagiosum Treatment Options First-Line: Surgical Excision Standard excision – preferred for solitary lesions (recurrence rate: 4–8%) Mohs micrographic surgery – recommended for high-risk areas (face, nose) or aggressive lesions Alternative Therapies Topical/Intralesional Agents 5-Fluorouracil (5-FU) – topical or injected, with high cure rates (~98%) Methotrexate (MTX) – intralesional injections (88% resolution rate) Imiquimod – topical immune modulator (effective in 9–11 weeks)

Answer 119

Causes and Risk Factors Primary Causes Chemotherapy drugs: Capecitabine (Xeloda) (most common) Liposomal doxorubicin (Doxil) 5-Fluorouracil (5-FU), cytarabine, docetaxel Targeted therapies: Sorafenib, sunitinib, regorafenib (tyrosine kinase inhibitors) Other medications: Certain antibiotics, antifungals, and multikinase inhibitors Risk Factors High drug doses or prolonged treatment Pre-existing peripheral neuropathy or circulation issues Heat, friction, or pressure on hands/feet (e.g., hot water, tight shoes, manual labor) Female sex, older age, and diabetes may increase susceptibility Symptoms and Grading Common Symptoms Early stage: Tingling, numbness, burning sensation Redness resembling sunburn. Progression: Swelling, blistering, peeling skin Painful cracks or ulcers (severe cases) NCI Grading System Grade Symptoms 1 Mild redness, swelling, no pain 2 Painful peeling, blisters, difficulty gripping/walking 3 Severe ulceration, inability to perform daily tasks 7 Diagnosis Clinical examination (history of chemotherapy + characteristic skin changes) Skin biopsy (rarely needed, unless ruling out graft-versus-host disease) Differential diagnosis: Hand-foot skin reaction (HFSR) from kinase inhibitors (thickened, calloused skin) First-Line Therapies Dose reduction or temporary discontinuation of the causative drug Topical treatments: Corticosteroids (e.g., clobetasol) for inflammation Dimethyl sulfoxide (DMSO) for drug leakage 10% urea cream for skin repair Symptom Relief Pain management: Acetaminophen, NSAIDs, or opioids (severe cases) Cold therapy: Ice packs (15–20 mins) to reduce burning Elevation to decrease swelling

Answer 120

1. Pustular psoriasis. *Generalized pustular psoriasis -life-threatening medical emergency Rapidly developing widespread erythema, followed by the eruption of white, sterile non-follicular pustules which coalesce to form large lakes of pus. -associated with systemic illness, such as fever, malaise, tachycardia, weight loss, and arthralgia. -common in existing or previous chronic plaque psoriasis, *Localized (palmoplantar) pustular psoriasis Lesions on the palms and soles, such as yellow-brown pustules within established psoriasis plaques, or redness, scaling, and pustules at the tips of the fingers and toes. 2. Erythrodermic psoriasis. 3. Chronic plaque psoriasis. 4. Scalp psoriasis. 5. Facial psoriasis. Well-demarcated plaques on the face, similar to those of chronic plaque psoriasis. Lesions which may affect the hairline. Possible mild scaling around the eyebrows and nasolabial folds 6. Flexural psoriasis. 7. Guttate psoriasis. 8. Nail psoriasis commonly affects fingernails than toenails (50% and 35% respectively), and may affect all parts of the nail and surrounding structures. common in people with psoriatic arthritiscommon in people with psoriatic arthritis ail pitting - most common finding. Discolouration (for example the 'oil drop sign') — orange-yellow discolouration of the nail bed. Subungual hyperkeratosis Onycholysis Complete nail dystrophy Types of Psoriasis 1. Plaque Psoriasis (Psoriasis Vulgaris) Most common type (80–90% of cases) Appearance: Well-defined erythematous plaques with silvery scales, typically on elbows, knees, scalp, and lower back Symptoms: Itching, pain, and cracking (fissures) in severe cases. Mild-Moderate: Topical therapy is first-line. Vitamin D analogues (e.g., calcipotriol) - first-line for body/limbs. Topical corticosteroids - for short-term use on body/limbs and essential for scalp, flexures, and face. Combination products (e.g., calcipotriol with betamethasone dipropionate) are highly effective. Moderate-Severe: (Affects >10% body surface area or resistant to topicals). Phototherapy: Narrowband UVB or PUVA. Systemic Non-Biologicals: Methotrexate, Ciclosporin, Acitretin. Biological Therapies: For severe, resistant disease. Includes TNF-alpha inhibitors (e.g., adalimumab), IL-17 inhibitors (e.g., secukinumab), and IL-23 inhibitors (e.g., guselkumab). Use follows NICE TA guidelines and requires eligibility criteria (e.g., failed standard systemics, Psoriasis Area and Severity Index (PASI) ≥10, Dermatology Life Quality Index (DLQI) ≥10). Topicals (Vitamin D analogues, corticosteroids) > Phototherapy > Systemics (e.g., Methotrexate) > Biologics (e.g., Anti-TNF, IL-17/23 inhibitors) 2. Guttate Psoriasis Triggered by streptococcal infections (e.g., strep throat) Appearance: Small, drop-like red/pink papules (1–10 mm) on the trunk and limbs Common in children and young adults; may resolve spontaneously or progress to chronic plaque psoriasis streptococcal infection. Topicals + treat trigger (e.g., antibiotics) > Phototherapy 3. Inverse (Flexural) Psoriasis Affects skin folds (armpits, groin, under breasts) Appearance: Smooth, shiny red patches without scales (due to moisture) Prone to fungal/bacterial infections 4. Pustular Psoriasis Localized (palmoplantar pustulosis) or generalized (Von Zumbusch psoriasis) Appearance: Sterile pustules on erythematous skin, often painful. Systemic complications: Fever, chills, electrolyte imbalance, and sepsis risk 5. Erythrodermic Psoriasis Rare but life-threatening (affects >90% of body surface) 8. Appearance: Widespread red, peeling skin resembling burns. Complications: Hypothermia, dehydration, infection, and heart failure 6. Nail Psoriasis Affects 50% of psoriasis patients (80% in psoriatic arthritis) Symptoms: Pitting, onycholysis (separation from nail bed), crumbling, and "oil drop" discoloration 7. Scalp Psoriasis Common first presentation Symptoms: Thick scales, itching, and temporary hair loss Complications of Psoriasis 1. Psoriatic Arthritis (PsA) Affects ~30% of psoriasis patients Symptoms: Joint pain, dactylitis ("sausage digits"), and spinal involvement Risk factors: Nail psoriasis, scalp involvement, and severe skin disease 2. Cardiovascular Disease Increased risk of heart attack (60%) and stroke (40%) in severe psoriasis Linked to chronic inflammation, obesity, and metabolic syndrome 3. Metabolic Syndrome & Diabetes 30% higher risk of type 2 diabetes Associated with insulin resistance and obesity 4. Mental Health Disorders Depression and anxiety due to stigma and chronic discomfort 60% report significant impact on quality of life 5. Inflammatory Bowel Disease (IBD) Higher risk of Crohn’s disease and ulcerative colitis 6. Eye Complications (Uveitis) Inflammation in ~7% of psoriasis patients Symptoms: Redness, blurred vision, and photophobia 7. Kidney Disease Chronic inflammation increases CKD risk Management of Psoriasis (NICE Guidelines) 1. Topical Therapies (First-line for Mild-Moderate Cases) Emollients: Essential for moisturizing and reducing scaling Corticosteroids (e.g., clobetasol) – reduce inflammation Vitamin D analogs (calcipotriene) – slow keratinocyte growth Calcineurin inhibitors (tacrolimus) – for face/flexures 5. 2. Phototherapy (Moderate-Severe Cases) Narrowband UVB – safer than PUVA, fewer side effects PUVA (Psoralen + UVA) – effective but increases skin cancer risk 3. Systemic Medications (Severe/Refractory Cases) Methotrexate – cheap but hepatotoxic (requires monitoring) Cyclosporine – rapid action but nephrotoxic 5. Acitretin (Retinoid) – helpful in pustular psoriasis 4. Biologics (Targeted Therapy) TNF-α inhibitors (adalimumab, infliximab) – for PsA IL-17/23 inhibitors (secukinumab, ustekinumab) – high efficacy JAK inhibitors (tofacitinib) – newer oral option 5. Lifestyle & Supportive Care Avoid triggers (stress, infections, alcohol, smoking) Moisturize daily (petrolatum-based emollients) Psychological support (therapy, support groups) Key Takeaways from NICE Guidelines Topical treatments are first-line for mild-moderate psoriasis Phototherapy is effective but requires specialist supervision Systemic/biologic therapy is reserved for severe cases Comorbidities must be screened (e.g., CVD, diabetes, depression) Patient education and self-management are crucial for long-term control

Answer 121

characterized by transient, pruritic wheals (hives) and/or angioedema. It is classified based on duration: Acute urticaria (<6 weeks duration) - Often allergic/trigger-mediated Chronic urticaria (>6 weeks) - Further subdivided into: Chronic spontaneous urticaria (CSU) - No identifiable external trigger Chronic inducible urticaria (CIndU) - Trigger-specific (e.g., cold, pressure) Pathophysiology Mast cell activation → histamine release → vasodilation and plasma extravasation In CSU, autoimmune mechanisms (anti-IgE or anti-FcεRI antibodies) are implicated in ~50% of case Bradykinin-mediated angioedema (e.g., ACEI-induced) follows a different pathway Clinical Features Wheals: Erythematous, edematous plaques with central pallor; individual lesions last <24h Angioedema: Deeper swelling (lips, eyelids); may persist up to 72h Dermographism: Wheals induced by stroking skin (common in CIndU) Diagnosis (NICE Recommendations) History: Focus on: Duration, timing, and distribution of lesions Potential triggers (foods, medications, infections, stress) Associated systemic symptoms (anaphylaxis risk) Physical exam: Assess for: Wheal morphology and dermatographism Thyroid abnormalities (linked to autoimmune CSU) Limited testing: CBC/diff (eosinophilia may suggest parasitic infection) CRP/ESR if systemic inflammation suspected Thyroid function tests (autoimmune association) Autologous serum skin test (ASST) for autoimmune CSU (specialist use) Management (Stepped Approach) Step 1: Non-sedating H1-antihistamines First-line: Cetirizine 10mg OD or loratadine 10mg OD NICE recommends up to 4x standard dose if standard dose ineffective (e.g., cetirizine 40mg daily) Step 2: Add alternative antihistamine or leukotriene antagonist Second agent: Fexofenadine or levocetirizine Montelukast 10mg OD (especially if aspirin/NSAID exacerbation) Step 3: Specialist therapies (for refractory CSU) Omalizumab (anti-IgE) - NICE-approved for CSU unresponsive to high-dose antihistamines Cyclosporine (for severe autoimmune CSU) Short-course oral corticosteroids (prednisolone 20-50mg OD for 3-7 days for acute flares) Patient Education and Monitoring Avoid triggers (e.g., aspirin/NSAIDs in susceptible patients) Cooling measures (cold compresses, loose clothing) Anaphylaxis awareness (prescribe epinephrine auto-injector if history of severe angioedema) Regular follow-up to assess treatment response and adjust therapy When to Refer to Specialist Care Urgent referral: Suspected anaphylaxis or airway angioedema Routine referral: Chronic urticaria unresponsive to high-dose antihistamines Diagnostic uncertainty (e.g., vasculitic urticaria) Need for omalizumab or other immunomodulators Key Takeaways Most cases are self-limiting; chronic urticaria (>6 weeks) requires systematic management. High-dose non-sedating antihistamines are mainstay (NICE supports up to 4x standard dose). Omalizumab is highly effective for refractory CSU. Avoid prolonged steroids; reserve for acute flares. Rule out underlying causes (e.g., infections, autoimmunity) in persistent cases.

Answer 122

Bartonella species are gram-negative, intracellular bacteria that cause a range of zoonotic infections in humans. The most clinically significant species include Bartonella henselae (cat-scratch disease), Bartonella quintana (trench fever), and Bartonella bacilliformis (Carrion’s disease). Below is a structured summary of epidemiology, transmission, clinical manifestations, diagnosis, and treatment based on current guidelines and research. Key Bartonella Species and Associated Diseases Species Disease Primary Reservoir Vector/Transmission B. henselae Cat-scratch disease (CSD), bacillary angiomatosis, endocarditis Cats (kittens) Cat fleas (Ctenocephalides felis), scratches/bites B. quintana Trench fever, chronic bacteremia, endocarditis Humans (homeless populations) Body lice (Pediculus humanus) B. bacilliformis Carrion’s disease (Oroya fever, verruga peruana) Humans Sandflies (Lutzomyia spp.) B. clarridgeiae Rare CSD-like illness Cats Fleas 2. Clinical Manifestations A. Cat-Scratch Disease (CSD) Symptoms: Primary lesion: Papule/pustule at scratch/bite site (3–10 days post-exposure) Lymphadenopathy: Tender, unilateral nodes (axillary, cervical) appearing 1–7 weeks later Systemic: Fever, fatigue; rare complications include neuroretinitis, encephalitis, or hepatosplenic abscesses High-risk groups: Immunocompromised patients (e.g., HIV) may develop bacillary angiomatosis (vascular skin lesions) or peliosis hepatis (liver lesions) B. Trench Fever (B. quintana) Symptoms: Cyclic fever, headache, bone pain (shins), maculopapular rash Complications: Culture-negative endocarditis, chronic bacteremia in homeless populations C. Carrion’s Disease (B. bacilliformis) Acute phase (Oroya fever): Hemolytic anemia, fever, high mortality (40% untreated) Chronic phase (verruga peruana): Nodular skin lesions resembling hemangiomas 3. Diagnosis Serology: IgG/IgM ELISA or IFA (cross-reactivity between species limits specificity) PCR: Preferred for tissue/valve samples (sensitivity: 92% in endocarditis) Culture: Requires prolonged incubation (up to 21 days); low yield for CSD Histopathology: Warthin-Starry stain shows bacilli in tissues (e.g., lymph nodes) 4. Treatment Recommendations A. Cat-Scratch Disease Mild cases: Self-limiting; supportive care (analgesics, warm compresses) Moderate-severe: Azithromycin (5-day course: 500 mg Day 1, then 250 mg Days 2–5 for adults) reduces lymphadenopathy Alternatives: Doxycycline, rifampin, or ciprofloxacin for disseminated disease B. Trench Fever & Endocarditis First-line: Doxycycline (4–6 weeks) + gentamicin (first 2 weeks) Surgery: Valve replacement often needed for endocarditis C. Carrion’s Disease Oroya fever: Ciprofloxacin or chloramphenicol (1–2 weeks) Verruga peruana: Azithromycin or rifampin 5. Prevention CSD: Avoid rough play with cats; flea control in pets B. quintana: Improve hygiene to eliminate body lice B. bacilliformis: Insect repellents in endemic areas (South America) Key Takeaways ✅ CSD is the most common Bartonella infection (linked to cats/fleas). ⚠️ Endocarditis requires prolonged antibiotics ± surgery. 🔍 PCR/serology aids diagnosis; cultures are low-yield. 💊 Azithromycin is first-line for CSD; doxycycline + gentamicin for severe infections.

Answer 123

A. Clinical History Onset and Course: Acute, chronic, or relapsing-remitting? Symptoms: Pruritus (itch) is extremely common (e.g., eczema, lichen planus). Pain can be a feature of blistering disorders (e.g., pemphigus) or vasculitis. Triggers: Medications, infections, sunlight, stress, or other environmental factors. Systemic Symptoms: Fever, arthralgia, malaise (suggestive of a systemic disorder like lupus or vasculitis). Past Medical and Family History: Personal or family history of other autoimmune or atopic conditions. B. Physical Examination (Morphology and Distribution) This is the cornerstone of diagnosis. Key elements to note: Primary Lesion: Macule, papule, plaque, nodule, vesicle, bulla, pustule, wheal. Configuration: Annular (ring-shaped), linear, grouped, discoid (coin-shaped), reticular (net-like). Distribution: Symmetrical vs. asymmetrical; photodistributed (sun-exposed areas); extensor vs. flexor surfaces; acral (hands/feet); intertriginous (skin folds); generalized. Mucous Membranes: Involvement of oral, genital, or ocular mucosa is a critical clue (e.g., pemphigus vulgaris, lichen planus, Stevens-Johnson Syndrome). C. Diagnostic Tests Skin Biopsy for Histopathology: The gold standard. A pathologist examines the tissue architecture and type of inflammatory infiltrate (e.g., lichenoid interface dermatitis in lichen planus or lupus; acantholysis in pemphigus; subepidermal blisters in bullous pemphigoid). Direct Immunofluorescence (DIF): Crucial for diagnosing immunobullous diseases. A fresh biopsy sample is examined for deposits of immunoglobulins (IgG, IgA, IgM) and complement (C3). Patterns are diagnostic: Pemphigus: IgG and C3 deposited on the surface of keratinocytes (fishnet pattern). Bullous Pemphigoid: IgG and C3 deposited in a linear pattern along the basement membrane. Dermatitis Herpetiformis: Granular IgA deposits in the dermal papillae. Serological Tests: Indirect Immunofluorescence (IIF): Detects circulating autoantibodies in the patient's serum. ELISA: Quantifies specific autoantibodies (e.g., anti-Dsg1/3 for pemphigus, anti-BP180/230 for bullous pemphigoid). Other: ANA, ENA, ANCA for connective tissue diseases and vasculitis. Other: Patch testing (for allergic contact dermatitis), potassium hydroxide (KOH) preparation to rule out fungal infections.

Answer 124

A. Autoimmune Blistering (Bullous) Diseases Characterized by autoantibodies against structural proteins that hold skin cells together. Pemphigus Vulgaris: Antibodies against desmoglein 3 (Dsg3). Flaccid blisters that rupture easily, leaving painful erosions. Oral involvement is common and often the first sign. Bullous Pemphigoid: Antibodies against BP180 and BP230 at the basement membrane. Tense, fluid-filled blisters on erythematous or urticarial plaques, often on flexural areas. Intense pruritus. Typically affects the elderly. Dermatitis Herpetiformis: Associated with celiac disease (gluten sensitivity). IgA antibodies against transglutaminase. Extremely pruritic grouped vesicles and papules on elbows, knees, buttocks, and scalp. B. Connective Tissue Diseases Often have systemic manifestations beyond the skin. Cutaneous Lupus Erythematosus (CLE): Acute CLE: Malar "butterfly" rash, photosensitivity. Subacute CLE: Annular or psoriasiform, non-scarring plaques, highly photosensitive. Chronic CLE (Discoid Lupus): Discoid plaques with scale, follicular plugging, scarring, and dyspigmentation. Dermatomyositis: Heliotrope rash (violaceous hue on eyelids), Gottron's papules (violaceous papules over knuckles), shawl sign, V-sign. Mechanic's hands and periungual telangiectasia are also classic. C. Papulosquamous Disorders Psoriasis: A chronic, immune-mediated (IL-17/IL-23 pathway) disorder. Well-demarcated erythematous plaques with silvery scale. Common distributions: scalp, elbows, knees, umbilicus, gluteal cleft. Nail pitting and onycholysis are common. Lichen Planus: "Pruritic, purple, polygonal, planar papules and plaques." Often involves wrists, ankles, and mucous membranes (reticular white streaks—Wickham's striae). Can cause scarring alopecia if on scalp. D. Urticaria and Hypersensitivity Reactions Chronic Spontaneous Urticaria: Recurrent wheals (hives) and/or angioedema for >6 weeks. Often autoimmune in nature (autoantibodies against IgE or its receptor). Drug Eruptions: Spectrum from simple morbilliform (measles-like) rash to severe cutaneous adverse reactions (SCARs): Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN): Life-threatening detachment of skin and mucous membranes. Often drug-induced. Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): Severe reaction with rash, fever, lymphadenopathy, and internal organ involvement. E. Vasculitis Inflammation of blood vessels leading to purpura (non-blanchable purple spots), palpable purpura, ulcers, and nodules. IgA Vasculitis (Henoch-Schönlein Purpura): Palpable purpura on lower extremities and buttocks, abdominal pain, arthralgia. Leukocytoclastic Vasculitis: Small vessel vasculitis often presenting as palpable purpura. F. Other Alopecia Areata: Autoimmune attack on hair follicles causing well-circumscribed, non-scarring hair loss. "Exclamation mark" hairs at periphery. Vitiligo: Autoimmune destruction of melanocytes, resulting in acquired, depigmented macules and patches.

Answer 125

Condition# Key Clinical Features #Most Commonly Associated Malignancies #Pathophysiology & Diagnosis #Management Acanthosis Nigricans -Velvety, hyperpigmented, thickened plaques in body folds (axillae, neck, groin). - Gastric adenocarcinoma (especially if sudden, severe, and in non-obese adults). Also other GI adenocarcinomas. Thought to be driven by tumor-secreted factors (e.g., TGF-α) stimulating keratinocytes. - Diagnosis: Clinical. Sudden onset should prompt urgent GI workup (endoscopy). Treat the underlying malignancy. Skin lesions may improve with treatment. - Topical retinoids or keratolytics for symptomatic relief. Dermatomyositis - Heliotrope rash (violaceous rash on eyelids), Gottron's papules (red/violet papules on knuckles), shawl sign, V-sign, mechanic's hands. - Proximal muscle weakness. Ovarian cancer, lung, gastric, pancreatic, breast, NHL. Risk is highest in adults >40yo. Autoimmune microangiopathy. Autoantibodies (e.g., anti-TIF1γ) are strongly associated with cancer. - Diagnosis: Clinical, elevated CK/aldolase, EMG, muscle/skin biopsy, MRI. Full malignancy workup is mandatory. Treat underlying cancer. - Immunosuppression (high-dose steroids, IVIG, methotrexate) for dermatomyositis. Necrolytic Migratory Erythema (Glucagonoma Syndrome) - A painful, migrating, erythematous rash with blistering and erosions. Often starts in perioral and perineal areas. - Glucagonoma (alpha-cell tumor of the pancreas). Due to severe amino acid deficiency and hyperglucagonemia. - Diagnosis: High plasma glucagon levels. CT/MRI to locate pancreatic tumor. - Surgical resection of the glucagonoma. Somatostatin analogs (octreotide) can improve symptoms. Nutritional support. Leser-Trélat Sign - eruption and rapid increase in number and size of seborrheic keratoses. - GI adenocarcinomas (stomach, colon), lymphomas, breast cancer. - Pathophysiology unclear. Diagnosis is clinical but controversial; must be a sudden eruption in a patient with cancer. - Focus on identifying and treating the underlying malignancy. Paraneoplastic Pemphigus - Painful stomatitis and polymorphic skin eruption (blisters, erosions, lichenoid plaques). - Non-Hodgkin lymphoma, chronic lymphocytic leukemia (CLL), Castleman's disease. Autoantibodies against plakin proteins causing acantholysis. - Diagnosis: Skin biopsy (direct immunofluorescence shows IgG and C3 deposition), serum antibodies. - Extremely difficult to treat. Address the underlying malignancy. Immunosuppression (steroids, rituximab, cyclophosphamide) is often used but response is poor. Bazex Syndrome (Acrokeratosis Paraneoplastica) - Psoriasiform, scaly plaques on ears, nose, fingers, toes, and nails (nail dystrophy). - Squamous cell carcinomas of the upper aerodigestive tract (e.g., larynx, esophagus, lung). Likely an immune cross-reaction. - Diagnosis: Clinical. Lesions are resistant to topical psoriasis treatments. - They often resolve with treatment of the primary tumor.

Answer 126

Condition# Key Clinical Features #Risk of Transformation #Diagnosis #Management Actinic Keratosis (AK) - Rough, scaly, erythematous patches on sun-exposed skin (face, scalp, hands). "Sandpaper" texture. - Low per lesion (<1% per year), but cumulative. Field cancerization means the entire area is at risk. - Clinical diagnosis. Dermoscopy shows a "strawberry" pattern. - Biopsy if indurated, thickened, or non-responsive to treatment. Field therapy: Treat the entire area (e.g., forehead, scalp). Options: 5-Fluorouracil (5-FU) cream, Imiquimod cream, Ingenol mebutate, Photodynamic Therapy (PDT). Lesion-directed therapy: Cryotherapy. Leukoplakia - White patch or plaque on mucosal surfaces (oral, genital) that cannot be scraped off. Variable (3-15% overall). Higher risk if on floor of mouth/ventral tongue, non-homogeneous, or in immunosuppressed patients. - Biopsy is mandatory to rule out dysplasia or invasive SCC. - Eliminate risk factors (tobacco, alcohol, ill-fitting dentures). Surgical excision is first-line for dysplastic or high-risk lesions. Erythroplakia - Velvety red patch on mucosal surface (oral, genital). Very high risk (>50%). Often represents severe dysplasia or carcinoma in situ at diagnosis. - Urgent biopsy is required. - Complete surgical excision is the treatment of choice due to the high malignant potential. Bowen's Disease (SCC in situ) - Well-demarcated, scaly, erythematous plaque on sun-exposed OR non-sun-exposed skin. - Progresses to invasive SCC in ~3-5% of cases. Diagnosis confirmed by biopsy. - Excision (standard of care). Other options: Cryotherapy, Curettage & Electrodessication, Topical 5-FU or Imiquimod, Radiotherapy. Lentigo Maligna - A large, irregularly pigmented, slowly expanding macule on sun-damaged skin (face, neck). A subtype of melanoma in situ. - Progresses to lentigo maligna melanoma (invasive melanoma) over years. Dermoscopy is crucial (asymmetrical pigmented follicular openings, rhomboidal structures). - Biopsy (often a broad punch or small incision to assess architecture). - Complete surgical excision with margin control (staged excision with Mohs surgery or peripheral margin assessment is preferred due to subclinical extension).

Answer 127

Malignancy #Key Clinical Features & Subtypes# Diagnosis #Management Basal Cell Carcinoma (BCC) - Nodular: Pearly papule with telangiectasia. Superficial: Scaly, pink patch. Morpheaform: Scar-like, ill-defined. - Shave or punch biopsy. - Surgical excision (Mohs surgery for high-risk areas like face, or high-risk subtypes). Other options: Electrodesiccation & Curettage (for low-risk), topical therapy, radiotherapy, vismodegib (for advanced/metastatic). Squamous Cell Carcinoma (SCC) - Hyperkeratotic nodule or plaque, often on sun-damaged skin. May ulcerate. Keratoacanthoma: A rapid-growing variant that can resemble SCC. - Punch or incisional biopsy. Surgical excision is primary treatment. Mohs for high-risk (large size, poor differentiation, perineural invasion, high-risk location). - Radiotherapy for non-surgical candidates. Cutaneous Melanoma - ABCDE rule: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolving. Subtypes: Superficial Spreading, Nodular, Lentigo Maligna, Acral Lentiginous. - Excisional biopsy (full-thickness to assess Breslow depth). Wide local excision. Sentinel lymph node biopsy for staging (if depth >0.8mm or other risk factors). - Advancing: Immunotherapy (pembrolizumab, nivolumab), Targeted therapy (for BRAF-mutated). Cutaneous T-Cell Lymphoma (Mycosis Fungoides) - Early: Patches/plaques that can mimic eczema or psoriasis. Late: Tumors, erythroderma. - Challenging; requires a high index of suspicion. Multiple deep punch biopsies are often needed for histology and immunophenotyping. - Skin-directed therapy for early stages (topical steroids, nitrogen mustard, phototherapy). Systemic therapy for advanced disease (interferon, retinoids, chemotherapy, targeted agents).

Answer 128

Xanthelasma Xanthelasma are yellowish papules and plaques caused by localized accumulation of lipid deposits commonly seen on the eyelid. They are also seen in patients without lipid abnormalities. Management of xanthelasma, options include: surgical excision topical trichloroacetic acid laser therapy electrodesiccation

Infectious and Derm Flashcards

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