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Flashcards in Pastest: Infectious disease Deck (69)
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Rash > Diagnosis

Buccal lesion:

Whitish papular (Koplik spot) > Measles

Flat, broad, whitish, wart-like (Condyloma latum) > Secondary syphilis



Florid erythematous rash, maculopapular rash (from behind the ear/face to caudally to trunk, arms) > measles

Transitory, erythematous rash (on ear, face, neck) > rubella

Slapped cheeks, erythematous rash over cheeks (spares forhead, nasolabial fold), lace-like reticular rash on trunk > parvovirus B19

Non-blanching petechial/purpuric rash > menongococcaemia

Symmetrical, non-pruritic, purple-pink/reddish-pink rash on trunk extremities, palms, soles > secondary syphilis

Elderly + slowly-growing lesion over that line on face + may ulcerate + no travel history > BCC

Oral mucous/ genital painful ulceration, multiple vesicles with ulceration, shallow ulcers +/- bilateral inguinal lymphadenopathy, shooting pain, urethral discharge > Herpes

Travel history to African countries, middle east, Syria + initial bite/nodule, gradually ulcerates > Leishmaniasis  

Children + multiple, vesicular/looking leisons > Molluscum 

After starting antibiotic (penicillin, amoxicillin, ampicillin) > itchy, maculopapular rash > Dx: EBV > IOC: Monospot test for heterophile Ab > Tx: supportive; if aplenomegaly > avoid contact sports

After 6weeks to 6months of infection > Rash = scaly of trunk, palms, face, soles + NO h/o penicillin + may H/O primary syphilis/chancre > Dx: Secondary syphilis

  •  Penicillin causes maculopapular rash, only if patient has underlying EBV = infectious mononeucleosis 

After a patch on trunk (= herald patch) > rash on trunk (distinct small oval lesions) > Dx: Ptyriasis rosea

Non-blancing rash + signs of meningism, photophobia > Dx: N. meningitides (meningococcus)



FBC > viral/bacterial disease

Normal WBC, Leukopaenia, Lymphopaenia >>> Viral disease

Leukocytosis >>> Bacterial disease


Clinical features + CSF findings >>> (Diagnosis) >>> Treatment 

Confusion >>> meningitis (also), encephalitis

Neck stiffness >>> meningitis, encephalitis (also)

If immunocompromised >>> fungal meningitis


CSF >>> differentiate between 3 types of meningitis +

ZN stain >>> do NOT rely on it, can often be negative in TB (given as a distraction)

Gm stain -ve >>> rules out bacterial; +ve >>> bacterial

  • gm -ve diplococci >>> Dx: Neisseria meningitides (Meningococcus)
  • gm -ve rods >>> Dx: Haemophilus influenzae, E. Coli, pseudomonas aeruginosa (pseudomonas is hospital acquired)
  • gm +ve diplococci >>> Dx: Streptococcus pneumoniae (pneumococcus)
  • Rash are present in both meningococcus and pneumococcus >>> so pattern of rash & gram stain in important 
  • Cold sores, elderly patient may be associated with pneumococcus 

CT scan >>> if meningeal enhancemnt >>> go for meningitis


Tx: (1st line)

TB meningitis >>> RIPES + Steroids

Viral meningitis/encephalitis >>> IV acyclovir

Bacterial meningitis >>> IV Cefotaxime (+/- add benzylpenicillin if <3m or >50years)

Fungal meningitis >>> anti-fungal (e.g. amphotericin B)



Dog bite >>> organisms

1. Pasteurella maltocida (most common)

2. S. pyogens

3. Capnocytophaga 


Animal bite > 1st line TOC



Travel history >>> diagnosis

West Africa & those countries (e.g. Gambia) >>>

1st to think: Malaria

High fever, rigors, diarrhoea, vomiting, hypotension >>> Malaria

Fever, headache, loose stools, +/- leukocytosis, thrombocytopaenia >>> Malaria >>> IOC: Thick blood film

  • Thick blood film shows: type of malaria + stages of parasite in RBC
  • (thin film to show a geater detail)

Fever, constipation >>> Typhoid

Fever, cough, sputum >>> Atypical pneumonia


*** Malaria prophylaxis do NOT exclude malaria (given as a distraction)


Businessman travelling to South Africa >>> fever, malase, LNpathy, acute nephritis + urine protein ++, blood ++  >>> Dx: Secondary syphilis (>nephrotic syndrome)

  • D/D: HBV, HCV
  • Plasmodium malariae causes nephrotic syndrome + membranous GN (but not acute nephritis)



Oral doxycycline

If the patient is pregnant >>> TOC: Chloramphenicol



HBV serology to diagnosis

In questions about HBV >>>

Step-1: Look for any,

+ve s Ag / +ve e Ag / +ve HBV DNA >>> Active infection (whatever other findings are)

  • Anti-HBc IgM +ve > Acute active hepatitis
  • Anti-HBc IgM -ve + Anti-HBc IgG +ve > Chronic active hepatitis/ Carrier active hepatitis
  • Hepatitis B vaccine is ineffective in acute/chronic active hepatitis
  • +ve e Ag indicates high infectivity 

+ve s Ag + -ve e Ag >>> Pre-core mutant HBV >>> do HBV DNA


Step-2: If not such > now look for any evidence of immunity,

both core Ab (IgG) + surface Ab >>> prior infection/latent infec.

surface Ab alone >>> Vaccinated

both core Ab + anti-HBe Ab >>> chronic carrier + low infectivity 


Surface Ab = Anti-HBs Ab

Core Ab = Anti-HBc Ab

Prior infection = now cleared

Latent infection = any immunosupression can reactivate

Pre-core mutant = Active disease + but due to genetic mutation > produce only s antigen, doesn't produce e antigen 


HBsAg & HBeAg is used to define phase of HBV

HBsAg is +ve in acute & chronic active cases > So, can't differentiate between these two > one isolated test that's only +ve in acute active disease > Anti-HBc IgM




Tenofovir disoproxil + Emtricitabine + Raltegravir 


Jarisch- Herxcheimer reaction occurs in - ?

  • Spirochete infection: Syphilis (Treponema pallidum), Lyme disease (Borrelia burgdorferi)
  • Relapsing fever (other borrelia species)
  • Leptospirosis
  • Q fever (Coxiella burnetii)



Neck stiffness + photophobia + multisystem failture (liver failure = high ALT/AST, high bilirubin; renal failure = high urea, high creatinine) ->>> D/D ?

 + Conjunctivitis > Leptospirosis (hepato-renal syndrome)

 + dry cough, pneumonia > mycoplasma pneumonia + multi-organ failure

 + low consciousness + very low/significant hypotension > meningococcal sepsis + multi-organ failure 


IOC for suspected legionella ?

Urinary antigen test


Fever + SOB + dry cough >>> Dx

Fever + SOB + dry cough > Atypical pneumonia

If lymphopaenia, hyponatraemia, deranged LFTs >> Dx: Legionella

If diarrhoea, air-conditioning >> Dx: Legionella

  • Temp for colonisation and multiplication: 20- 45 C
  • Droplet diameter for infection: <5 micrometer

If target lesions on skin (erythema multiforme) >> Dx: Mycoplasma

If CXR shows patchy (reticulo-nodular) shadow >> Dx: Mycoplasma

If h/o bird exposure >>> Dx: Chlamydia psittaci


Fever + SOB + h/o influenzae >> Dx: Staphylococcal pneumonia

Fever + SOB + cavitary lesion >> Dx: Klebsiella pneumonia, Staphylococcal pneumonia 



Neurological infective diseases: D/D to Dx

Trismus (1st), then rigidity & spasm + trismus (lockjaw), risus sardonicus, opisthotonus (arched back, hyperextended neck), spasms (e.g. dysphagia) >>> Dx: Tetanus


Descending flaccid paralysis of autonomic & motor system (e.g. speaking: dysarthria, swallowing:dysphagia, visual: ptosis, neck: difficulty lifting head- neck etc.) + NO sessory change + NO LOC + h/o IV drug use >>> Dx: Botulism [from visual, speech, swallowing> neck, arms (before going into) > respiratory system

Risk factors of btulism: canned food, improperly preserved food, open wound, IV drug use; Cause: bacterial neurotoxin by 'clostridium botulinum'


Ascending paralysis + reduced power in limbs + NO sensory change >>> Dx: GBS


IV drugs user + destruction around injection site + severe sepsis >>> Dx: Injection anthrax


Many weeks/months after dog bite > encephalomyelitis, confusion, hallucination, hydrophobia, hypersalivation >>> Dx: Rabies (also prodrome: headache, fever, agitation)


List of notifiable diseases to CCDC (consultant in communicable disease control)/ UK Gov/ public health england

Diseases notifiable to local authority proper officers under the Health Protection (Notification) Regulations 2010: (A to Z)

  • Acute encephalitis
  • Acute infectious hepatitis
  • Acute meningitis
  • Acute poliomyelitis
  • Anthrax
  • Botulism
  • Brucellosis
  • Cholera
  • Diphtheria
  • Enteric fever (typhoid or paratyphoid fever)
  • Food poisoning
  • Haemolytic uraemic syndrome (HUS)
  • Infectious bloody diarrhoea
  • Invasive group A streptococcal disease
  • Legionnaires’ disease
  • Leprosy
  • Malaria
  • Measles
  • Meningococcal septicaemia
  • Mumps
  • Plague
  • Rabies
  • Rubella
  • Severe Acute Respiratory Syndrome (SARS)
  • Scarlet fever
  • Smallpox
  • Tetanus
  • Tuberculosis
  • Typhus
  • Viral haemorrhagic fever (VHF)
  • Whooping cough
  • Yellow fever

Report other diseases that may present significant risk to human health under the category ‘other significant disease’.


*** HIV is not a notifiable disease: Newly diagnosed HIV cases are indcluded in national resgister.


Fever + sore throat > Diagnosis 

Both > marked lymphocytosis, hepatosplenomegaly, anaemia
If an immunocompromised patient > Dx: CMV
If renal transplant patient > Dx: CMV
If negative IgG for EBV > Dx: EBV (A distractor)

  • IgG can be regularly negetive for EBV; Since, IOC is IgM to EBV (by heterophile antibody test or Monospot test)


EBV vs Streptococcal pneumoniae (group A)
Both: palatal petechiae (absent in other viral diseases)
If uvular oedema and/or raised ESR > Dx: EBV
If hepatosplenomegaly > Dx: EBV
If rash after antibiotics > Dx: EBV
If no uvular oedema + normal ESR + no rash after antibiotics > Dx: Streptococcal pneumoniae 

  • In a patient with uvular oedema and/or raised ESR or any way with confirmed case of EBV > if streptococcal pneumoniae is found in throat culture > it is not infection, that is bacterial colonisation (so, do NOT treat that)


EBV vs HIV seroconversion illness:
Lymphopaenia > Dx: HIV seroconversion illness 
Marked relative lymphocytosis >/= 60%, atypical lymphocytes >/= 10%, leukocytosis, atypical monocytes > Dx: EBV


If flu-like illness + gastroentritis + NO bone marrow supression, pharyngitis, splenomegaly > Dx: HAV
NO gastroenteritis + possible bone marrow supression (anaemia), pharyngitis, splenomegaly > Dx: EBV


EBV > drug-induced rash vs viral rash of EBV/infectious mononucleosis:
Both: maculopapuar
Pruritic + prolonged > Dx: Drug-induced (due to amoxicillin/ampicillin/penicillin in EBV patient)
Non-pruritic + rapidly disappears > Dx: Early viral rash of EBV


Clinical triad for EBV: fever + pharyngitis + lymphadenopathy 

Specifics for EBV:
Bilateral posterior cervical LNpathy > Dx: EBV

Criteria to rule out EBV: Normal leukocyte count or lymphonaemia/leukopaenia


Other important features of EBV:

*hepatitis, abdominal pain, jaundice, deranged LFTs (high ALT, AST, bilirubin etc.)
*Splenomegaly in 50% > splenic rupture
* enlarged tonsils
*Haemolytic anaemia, secondary to cold aglutinin 


IOC for group A streptococcal infection >>> ASO titre

Rapid screening test for EBV >>> Serological test:

  • Monospot test > to detect heterophile antibodies in serum , against viral coded proteins: 85% sensitivity
  • False -ve (monspot -ve glandular fever) > outside of classic 15-25years range
  • False +ve in pregnancy, autoimmune disease

Definitive test for EBV >>> serum IgM antibodies to EBV capsid antigen (VCA)


Mycobacterium or Acid-alcohol-fast bacilli or AFB (Acid-fast bacilli): D/D to Dx

Skin biopsy:
Multiple acid-alcohol fast bacilli > multibacillary: lepromatous leprosy
Limited one/few AFB > paucibacillary: tuberculoid leprosy


Extensive/multiple skin plaque + symmetrical nerve involvement > lepromatous leprosy
Limited skin plaque + asymmetrical nerve involvement > tuberculoid leprosy
Fish trunk granuloma in hand + handling of aquarium, fresh water, salt water, swimming > Mycobacterium marinum 




Travel history:

D/D to Dx

Travel to to india, south asia, east asia: 

  • Fever, night sweat, weight loss, raised inflammatory markers >>>
    • Neutrophilia, deranged LFTs, non-caseating granuloma >>> Brucellosis (gram -ve bacillus)
    • Lymphocytosis, caseating granuloma, other classical features of TB >>> TB (blood culture is not usually +ve, culture of respiratory secretion takes weeks to yeild bacteria)
    • Ingestion of unpasteurised milk, exposure to infected cattles >>> Brucellosis (More common in middle east, north europe, north america)
      • hepatosplenomegaly
      • sacroilitis: spinal tenderness
      • spondylitis > associated rheumatic features (about 50% of cases)
      • complications: osteomyelitis, infective endocarditis, meningoencephalitis, orchitis, leukopenia is common
      • Screening: Rose bengal plate test
      • Confirmatory: Brucella serology 

Travel to tropics, india & return:

  •  Fever, headache >>>
    •  Constipation, sparse generalised rash, small papules >>> Dx: Typhoid
      • though relative tachycardia in other sepsis condition, here it has relative bradycardia (even around 70 is relative bradycardia for sepsis patient)
      • early disease may have diarrhoea for a short period; later may develop hepatosplenomegaly 
    • Dry cough, couple episodes of slighly loose stools, haemodynamically stable, relative bradycardia, palpable spleen, Gm -ve bacilli > Dx: Enteric fever
      • Abdominal pain, rose spots may also be found
      • Enteric fever is caused bby S. typhi and S. paratyphi
    •  Loose stools/diarrhoea, haemodynamically unstable. Gm -ve bacilli, +/- urinary S/S, renal angle tenderness > Dx: E. Coli
    • Intermittent abdominal bloating + irritable bowel syndrome (diarrhoea and constipation) + NO rash >>> Dx: Giardiasis by Giardia lamblia 
    • Catholic priest + Trip to india + flu-like illness + fever, myalgia, RUQ pain, deranged LFTs: high bilirubin, high ALP, very high ALT + took all recommended vaccines and malaria prophylaxis +/- low platelets > HEV
      • Catholic priest > excludes sexually or blood-related transmitted infections (HBV, HCV)
      • taken all vaccines > would prevent against HAV (not full protection against HEV)
      • periodic fever + bone pains + aches + low platelets > would Dx: Dengue
      • HEV is an RNA herpes virus with 4 genotypes: Mainly occurs in South Asia, Central Asia, Middle east, North Africa
      • It is acquired faeco-ral route, NO chronic form, high mortality in endemic areas; Most deaths occurs in pregnant female in their last trimester of pregnancy
      • IOC: IgM anti-HEV in serum ; NO treatment & NO vaccine
    • After 4-7days (tropical Queensland, india) > headache, flu-like symptoms + generalised rash + leukopaenia, lymphopaenia >>> Dx: Dengue
    • After 4-6weeks + fever, anorexia, malaise, splenomegaly, LNpathy, fatigue +/- thrombocytopaenia >>> Dx: EBV
      •  Normal WBC/Low WBC rules out EBV
      • Acute onset rules out EBV
    • Fever > headache. malasie, myalgia +/- jaundice, hepatosplenomegaly + No rash >>> Dx: Malaria falciparum
    • Fever, headache, malaise, myalgia, nausea, vomiting, photophobia + NO generalised rash + NO abdominal pain  > D/D: Influenzae  
    • Sickle cell anaemia patients + pancytopaenia + rash in cheeks >> Dx: Parvovirus
      • Generalised rash rules out parvovirus
      • Mild-self limiting disease in children

Travel to African countries:

  • non-specific: lathergy, night sweats, anorexia, gradual weight loss; + pancytopenia + hepatosplenomegaly + raised ALT + raised ALP + erythematous plaque on buttock >>> Dx: Visceral leishmaniasis > TOC: Na stibogluconate IV
    • S/E of Na stibogluconate: ECG changes of arrythmia, acute (chemical) pancreatitis,; (nausea, fatigue, abdominal pain)
    • Alternative therapy: Pentamidine
  • "Amastigote" from lymph node, bone marrow, spleen >>> Dx: Leishmaniasis
  • Travelling to 'Sierra Leone' rural > high fever, diarrhoea, vomiting > D/D: Ebola >> Send the patient direct to an isolation unit
    • Sierra leone is ond of the "prevalent regions" for Ebola virus >>> send the patient to an isolation unit (as s protocol for escorting suspected patients)

Travel to East-Asia, Thiland, Africa:

  •  h/o eating local food >>> watery diarrhoea + eosinophilia + larvae in stool of strongyloides >>> Dx: S. stercoralis
  • From Uganda + high eosinophil + urticarial rash over buttock, waist, diarrhoea, abdominal pain >>> Dx: S. stercolaris
  • From Thiland, elephant Safari > denies other sexual contacts + generalised itch, dry cough, diarrhoea + high eosinophil count >>> Dx: S. Stercoralis >>> Tx: Ivermectin
  • Gradual weight loss + intermittent IBS + chronic dry cough + significant gradual weight loss + high eosinophil >>> Dx: S. stercoralis
    •  It is more common in tropics, subtropics, far-east
    • The most likely risk factor of S. stercoralis is >>> walking barefoot
    •  Chronic S. stercoralis infection >>> vague symptoms of abdominal pain, features of malabsorption, eosinophilia, diarrhoea, urticaria
    • It causes marked eosinophilia > hallmark of tissue invasive helminth infection
    • Diagnosed by:
      • Stool/duodenal fluid > larvae
      • Antibodies (mainly in chronic infections) 
    • TOC: Ivermectin (highest rate of eradication = 97%) and Alternative: Albendazole (only if ivermectin is unavailable) 

Travelling to certain tropicals, Guatemala:

  • Fully vaccinated prior travel + malaria prophylaxis >>> Vegetraian & ate salads-fruits + Chronic severe diarrhoea + no response to ciprofloxacin & metronidazole (=not bacterial) >>> Dx: Ciclospora Cayetanesis >>> TOC: Co-trimoxazole 
    • Immunocompromised are particularly affected
    • Varied presentation depending upon person's immune system
    • Flu-like illness >>> incubation around a week
    • NO alternatives to Co-trimoxazole yet
    • Co-trimoxazole is used in typically in PCP pneumonia 

*  Swiming in fresh water >>> Dx: Schistosomiasis

  • eosinophilia (maybe) + haematuria (due to colonisation around venous plexus in urinary bladder) >>> Dx: S. haematobium
  • Africa + malaise + abdominal pain + frequent blood-stained stool >>> Dx: S. mansoni

* Marked lymphoedema >>> Dx: Wucheria bancrofti 


Cerebral abscess > initial IV antibiotics > oral antibiotic during discharge = antibiotic with best or broadest cover for anaroebic organism of this condition

(Antibiotics with anti-anarobic activity, with no anti-anarobic activity)

Co-amoxiclav (Amoxicillin + Clavulanic acid) >>> covers against:

  •  Beta lactamase producing gram +ve organism + anarobes
  •  Adequate brain penetration 
  • Amoxicillin alone do NOT cover enough against anarobes 


Antibiotic with anti-anarobic activity:

  • Penicillins
  • Cephalosporins (except Ceftazidime)
  • Erythromycin 
  • Metronidazole
  • Tetracycline

Antibiotic with no anti-anarobic activity:

  • Gentamicin
  • Ciprofloxacin
  • Ceftazidime 


Paragonimiasis vs TB vs Sarcoidosis

Granuloma: D/D:

  •  Sarcoidosis
  •  TB
  •  Paragonimiasis

Haemoptysis, cavitating lesion, productive cough: D/D: (absent in sarcoidosis)

  • TB: culture for AFB +ve, NO urticaria, NO eosinophilia 
  • Paragonimiasis: culture for AFB -ve. urticaria, eosinophilia 


Time course of HIV after initial infection

  1. After infected with HIV >>> 2-12 weeks  (mainly 2 to 4 weeks, rarely up to 10months) >>> HIV seroconversion >>> Latent / Asymptomatic period of 5-10years (even physical examination is normal, 1/3rd can be generalised LNpathy)
  2. After 18 months of infection >>> CD4 count goes below 500
  3. At average 5-10years (if kept untreated) >>> CD4 count goes below 200 = develops AIDS = AIDS defining illness


Abnormal prion protein in brain is related to > ?

CJD (Cruetzfeldt-Jacob disease)


Diarrhoea/Vomiting >>> Dx

Without given history of food/travel:

  • Watery diarrhoea (frequently) + fever + history of antibiotics treatment (due to any cause) >>> Dx: Pseudomembranous colitis = Clostridium defficile infection/enterocolitis
    • initial: mild self-limiting diarrhoea >>> to fulminating toxic megacolon
    • tend to have week or more before seeking medical attention
    • Due to diarrhoea > may have changes in electrolytes, high urea, creatinine, CRP
    • TOC: Oral metronidazole or vancomycin + re-hydration
  • Bloody diarrhoea + abdominal pain + diabetic patient + high serum lactate >>> Dx: Acute mesenteric ischaemia

With given history of food/travel:

  •  Contaminated food > bloody diarrhoea >>> Dx: EHEC (Enterohaemorrhagic E. Coli) 
  •  Contaminated meat, egg, poultry, dairy products > acutely > abdominal pain, diarrhoea +/- headache >>> Dx: Salmonella gastroenteritis (may have septicaemia); no person-to-person spread, but many people may/may not expose to one site
  •  Contaminated food or dairy products > within 6 hours > severe vomiting (only) >>> Dx: Staphylococcus aureus toxin (contaminated from small abscess, whitlow, discharging lesion > food > warm + not fully cooked); may also have nausea, abdominal cramps, followed by diarrhoea; short-lived > resolved by 24hours)
  • Acute presentation > abdominal pain, diarrhoea, blood, mucous >>> Dx: Shigella (bloody diarrhoea) +/- copious amount (electrolyte abnormalities due to diarrhoea & tender RUQ may follow)
  • Children nursuries, toddler day-care >>> Dx: Shigella
  • Children of nurseries + wrokers (multiple cases at a time); (human to human transmission is possible) >>> Dx: Shigella
  • Contaminated fruits >>> Dx: Shigella
  • H/o travel to Nile cruise >>> Dx: Shigella
    • NO vomiting in shigella
    • Shigella is highly infectious, passed via feco-oral route, aerobic, non-motile, gram -ve bacilli; > Mainstay of Tx: ORT, AB of choice: 3rd gen. Cephalosporin
    • Shigella is widespreadly resistant against penicillin, and ciprofloxacin
    • Self limiting in majority; indication of antibiotics:
      • elderly, the infirm, and who work in childcare settings
    • They improve symptoms, shorten duration, and reduce spread
  • Contaminated water, milk, poutry > abdominal pain, fever, diarrhoea (bloody) >>> D/D: Campylobacter (no human to human transmission, all exposed to one source)
  • Chronic watery diarrhoea/explosive diarrhoea + flatulence + weight loss (due to malabsorption) +/- abdominal pain >>> Dx: Giardiasis
    •  Giardia is flagellated protozoa > > foecal-oral spread > infection of duodenum and jejunum  
  • Diarrhoea (NOT bloody), vomiting, malaise, same group of people of same place >>> Dx: Rota virus 
  • Non-bloody diarrhoea + vomiting (usually in group of people) >>> Dx: Norovirus (winter vomiting virus)
  • Watery Diarrhoea in HIV-immunosupressed patients >>> Dx: Cryptosporidium (less commonly blood, self limiting, but can be very dangerous)
    • CD4 count: 100 to 300 > think Cryptosporidium (profuse watery diarrhoea)
    • CD4 count: <100 > think CMV (bloody diarrhoea)
    • CD4 count <50 > think Micropolyspora (profuse watery diarrhoea)
    • Some text says: CMV has CD4 <100, but it is the most common when CD4 <50 ...... So, consider it when HIV + bloody diarrhoea + CD4 <100 

Time period between food intake & symptoms:

  • 12-48hours >>> diarrhoea + vomiting >>> Dx: Salmonella typhi/paratyphi
  • 12-36hours >>> diarrhoea + vomiting + muscle weakness >>> Dx: Clostridium botulinum 
  • 1-5days >>> profuse watery diarrhoea >>> Dx: Vibrio cholerae 
  • 2-3days (48-72hours) >>> bloody diarrhoea, mucous-rich >>> Dx: Shigella 

HIV patient + very recent history (days) of anal inter-course >> bloody diarrhoea with mucous >>> Dx: Shigella

  • Cryptosporidium has profuse watery diarrhoea
  • Microsporidum has large volume watery diarrhoea
  • CMV has bloody diarrhoea but + need more long time to develop + CD4 <100

West African + chronic diarrhoea & weight loss for 10 weeks > episode of shingles 5weeks back + (headache, neck stiffness, increasing confusion) for few days + no mass lesion + 7th nerve palsy + CD4 <100 + raised ICP (= bilateral papilloedema) >>> Dx: Cryptococcus neoformans >>> TOC: Amphotericin B + Fluocytosine  




Features of Viral infection of eye:

to Dx

  • Keratitis + dendritic ulceration of cornea >>> Dx: Herpes Simplex Virus (HSV)
    • Acute pain, conjunctival injection, blurring of vision
    • Risk of corneal blindness >> so, urgent treatment
    • TOC: Topical Acyclovir
    • C.I: Topical steroids
    • D/D of keratitis: reduced tear formation >>> dry eyes + keratitis + NO corneal ulcer
  • Conjunctivits + Gastroenteritis >>> Dx: Adenovirus 
  • Conjunctivits  + Developing countries with poor hygiene + >>> (Trachoma, comes from flies) >>> Dx: Chlamydia trachomitis
  •  HIV patient or immunocompromised patient >>> D/D: CMV or HSV
    • CMV retinitis is more common
    • HSV can cause acute ncrotising retinitis in them


Jaundice >>> Dx

  • Hepatosplenomegaly + mild high AST/ALT, very high bilirubin, very high creatinine >>> Dx: Leptospirosis (Weil's disease) > TOC: IV Penicillin 
  • Sewage worker >>> Dx: Leptospirosis
  • Fishing trip, arthralgia, myalgia, dry cough, jaundiced sclera >>> Dx: Leptospirosis
  • Travel by river side, Very high bilirubin, mild high creatinine, very high ALT, very high ALP >>> Dx: Leptospirosis
    • may also have purpuric rash, scattered coarse crackles on auscultation, RUQ pain 
    • Possibility of exposure to 'rat urine' near the river bank
    • Course of leptospisosis: After 2 to 30days of incubation period >>> abrupt onset of 'flu-like symptoms' >>> After 5-days of that illness >>> jaundice, coagulopathy
    • Tx: Doxycycline, Penicillin, Cephalosporin & measures to reduce the rodent population 


  • Incubation 2-6 weeks >>> Flu-like illness (fever, malaise, anorexia, nausea. myalgia) > then, more prominent rise of AST/ALT, high bilirubin, normal creatinine >>> Dx: HAV
    • Africa, South america emdemic region


  • high AST/ALT, high bilirubin, fever, pharyngitis, lymphocytosis, anaemia +/- hepatosplenomegaly + immunocompromised/HIV/renal transplant >>> Dx: CMV
  • high AST/ALT, high bilirubin, fever, pharyngitis, LNpathy, lymphocytosis, +/- hepatosplenomegaly >>> Dx: EBV


  • Hepatomegaly + Ascites + Abdominal pain + NO fever >>> Dx: Budd-Chiari syndrome (occlusion of draining hepatic veins)


  • Bloody diarrhoea + anaemia + Low platelets + deranged LFTs (= hepatic injury)  >>> Enterotoxigenic E. coli O157 (= Haemolytic uraemic syndrome = HUS)
    •  Microangiopathic intravascular haemolytic anaemia


S/E of internferon-alpha (IFN-alpha) + Ribavirin therapy for HCV

Interferon-alpha (IFN-alpha) [S/C] >>>

  • Flu
  • Depression, emotional lability, mood changes
  • Fatigue
  • Thyroiditis
  • Low WBC (Leukopaenia)
  • Low platelet (Thrombocytopaenia)

Ribavirin PO >>>

  • Haemolytic anaemia (most common S/E), cough
    •  reduces Hb up to 20g/L > so, it is avoided in >
      • Previous h/o blood disorder
      • Elderly
      • Heart disease
  • Teratogenic (prevent pg during & up to 1 year from Tx; some say 6months, whatever sex is being treated)

* Viral genotype 2, 3, 3a (chronic infection) are more likely to respond to Rx

* genotype 4 has less responsiveness

* Telepravir for HCV can cause hypocalcaemia

* Rx response is checked by ALT level and viral load

* HCV can raise AST/ALT transaminases & creatinine (by GN); these are not by drugs


Vaccination in a COPD patient

  • Annual influenzae vaccine (yearly basis- against influenzae virus (not against haemophilus influenzae type B = Hib)
  • 5-yearly pneumococcal vaccine (Against streptococcus pneumoniae)

*** influenzae vaccine needed in annually post-splenectomy patient is also against influenzae virus (not against Hib; Hib vaccine against type haemophilus influenzae B is given 14days after emergency splenectomy or 14days = 2weeks before elective splenectomy)


Indication of influenzae vaccine

  • Patients in chronic care facilities (e.g. especially the elderly)
  • Chronic cardiopulmonary, lung disease, renal disease, diabetes mellitus, haemoglobinopathies 
  • the immunocompromised
  • post-splenectomy



Incubation period ?

Duffy antigen on RBC is protective against ?

Vector ?

Liver hypnozoites by ?

Life cycle present in P. vivax, but not in falciparum ?

  • Incubation period = over 1 week; p. falciparum has shorter, others 1-2weeks; can occur over several weeks > however, over several months (if partially treated)
  • Duffy antigen in RBC is protective against >>> P. vivax
  • Vector: Anopheles mosquito 
  • Liver hypnozoites is formed by >>> P. vivax and P. ovale (not by falciparum)
  • Life cycle present in P. vivax, but not in falciparum ? >>> Liver hypnozoites


*** Aedes is the vector for > dengue. yellow fever. Zika virus


Malaria life cycle

  • All forms of malaria create gametocytes >>> taken up by the mosquito >>> go onto develop oocytes and >>> eventually, sporozoites >>> injected in to human host
  • After initial invasion and development of schizonts in the liver >>> rupture >>> releases merozoites in blood stream >>> go and infect erythrocytes >>> replicate in RBC & rupture >>> releases further merozoites
  • Before rupture and propagation of the erythrocytic stage >>> the form within erythrocytes = trophozoites: immature are the risng-stage, then followed by mature erythrocytes 
  • Liver hypnozoites are dormant stage in liver (for P. vivax & P. ovale =  benign malaria) >>> can reactivate after a signifcant time >>> lead to relapse
  • Liver hypnozoites are not seen in falciparum
  • TOC to eradicate liver hypnozoites >>> primaquine (given only in vivax and ovale)
  • If we give quinine therapy in falciparum (TOC: Artesunate) >>> NO need to give primaquine >>> give fansider (pyrimethamine + sulfadoxine) or tetracycline >>> cover the possibility of low-grade quinine resistance