Infectious Diseases & Adverse Drug Reactions Flashcards

Question

When are the following swabs used?

Answer 1

**Fever**: > 37.5o **PUO**: Unexplained fever despite extensive investigation for longer than 2-3 weeks

Answer 2

**TB Tx** - DOTT - IREP 2 months - IR 4 months - Quinolones, macrolides, streptomycin for MDR

Answer 3

**Glandular Fever = Infectious mononucleosis (Kissing disease) = Epstein-Barr Virus**

Answer 4

EBV infects B lymphocytes in mucosal epithelium (e.g., oropharynx, cervix) via the CD21 receptor → infected B lymphocytes induce a humoral (B-cell) as well as a cellular (T-cell) immune response → an increased concentration of atypical lymphocytes in the bloodstream, which are CD8+ cytotoxic T cells that fight infected B lymphocytes.

Answer 5

Splenomegaly can lead to a potentially life-threatening splenic rupture! In most cases, a maculopapular rash occurs due to empiric administration of aminopenicillins, and not due to EBV infection.

Answer 6

**Mononucleosis-like syndromes** 1. Streptococcal pharyngitis, tonsillitis 2. Acute HIV infection 3. CMV infection (CMV mononucleosis) 4. Viral hepatitis 5. Toxoplasmosis 6. Diphtheria 7. Acute leukemia

Answer 7

**Other organ systems:** 1. Upper airway obstruction due to oropharyngeal inflammation and enlarged lymph nodes 2. Splenic rupture 3. Oral hairy leukoplakia (typically in HIV patients) 4. Acute renal failure 5. Pericarditis/myocarditis 6. Pneumonia 7. Otitis media

Answer 8

**Epidemiology** - Found predominantly in Australia, Papua New Guinea, the Solomon Islands, and other parts of Southeast Asia. - Outbreaks during summer and early autumn. **Aetiology:** - **Pathogen**: Ross River virus (RRV) - **Vectors**: mosquitoes (Aedes vigilax, Aedes camptorhynchus, Culex annulirostris, and Aedes aegypti) - **Reservoirs**: wallabies, kangaroos, possums, horses - **Route of transmission**: Mosquito bite, Human-mosquito-human transmission, Human-to-human: blood transfusions from an infected host

Answer 9

**Diagnostics** 1. Laboratory studies: ↑ ESR 2. Serology (gold standard): IgM and/or rising levels of IgG antibodies detected using ELISA 3. PCR 4. Viral culture **Differential diagnosis** 1. Barmah Forest virus 2. Chikungunya virus

Answer 10

**Epidemiology of Dengue** - **Distribution**: tropical regions worldwide, particularly Asia (e.g., Thailand) - **Incidence**: Most common viral disease affecting tourists in tropical regions, ∼ 400 million infections per year worldwide **Pathogen**: Dengue virus (Serotype: DENV 1–4). RNA virus of the genus Flavivirus **Transmission route** - Vector-borne: mosquitoes most commonly from the species Aedes aegypti

Answer 11

- If symptoms appear more than 2 weeks after returning from a dengue-endemic region, it is very unlikely that dengue is the cause. - Severe dengue is more frequent in individuals who experience a repeat infection with a second serotype, especially serotype 2.

Answer 12

**Laboratory tests** 1. Leukopenia 2. Neutropenia 3. Thrombocytopenia 4. ↑ AST 5. Hct significantly increased or decreased in DHF (due to plasma leakage)

Answer 13

1. Chikungunya fever and other viral hemorrhagic fevers 2. Malaria 3. Zika virus infection Severe hemorrhagic manifestations with shock and death as well as decreased neutrophil and platelet counts are more indicative of Dengue fever than Chikungunya fever.

Answer 14

**Cellulitis**: local infection of the deep dermis and subcutaneous tissue

Answer 15

**Pathophysiology of Cellulitis** - Entry is commonly via a minor skin injury. - May also be secondary to a systemic infection. - In cellulitis, the most common point of entry for the pathogen is a small skin lesion (e.g., interdigital tinea pedis). **Aetiology** - Beta-hemolytic streptococci: mostly group A Streptococcus (S. pyogenes) - Less common pathogens for cellulitis: - S. aureus - Pasteurella multocida (gram-negative, encapsulated coccobacillus): secondary to dog and cat bites. GAS is the most common cause of nonpurulent skin and soft tissue infections (i.e., erysipelas, cellulitis).

Answer 16

**General principles** - Empiric antibiotic therapy active against streptococci and S. aureus is the mainstay of treatment for nonpurulent SSTIs. - Treatment should also include the control of any predisposing factors (e.g., edema, fungal infections). **Antibiotic therapy** - Systemic antibiotic therapy is usually required. - Empiric regimens should usually cover Streptococcus spp. and S. aureus. - Antibiotics should be targeted against gram-positive pathogens and provide broad-spectrum coverage in severe cases. **Supportive care** - Elevation of the affected limbs. - Rest and acute pain management as needed.

Answer 17

**Cerebral amebiasis:** A rapidly fatal necrotizing encephalitis results from infection with Naegleria species, and a chronic granulomatous meningoencephalitis has been associated with infection with Acanthamoeba. The amebae may be difficult to distinguish morphologically from activated macrophages. Methenamine silver or PAS stains are helpful in visualizing the organisms, although definitive identification ultimately depends on immuno- fluorescence studies, culture, and molecular methods.

Answer 18

**Clinical features of Salmonella gastroenteritis ** 1. Duration: 3–7 days 2. Fever (usually resolves within 2 days) & chills 3. Headaches 4. Myalgia 5. Severe vomiting 6. Abdominal pain 7. Inflammatory (watery-bloody) diarrhea

Answer 19

- Antibiotic treatment of nontyphoidal Salmonella enteritis is not indicated for otherwise healthy patients without risk factors for complications. - Initial intravenous therapy is recommended in the following situations: 1. when oral therapy is not possible 2. in children aged 1 to 3 months 3. in patients with bacteraemia, endovascular infection or osteoarticular infection.

Answer 20

Streptococcal pharyngitis, which is the major antecedent of poststreptococcal glomerulonephritis, is marked by edema, epiglottic swelling, and punctate abscesses of the tonsillar crypts, sometimes accompanied by cervical lymphadenopathy. Swelling associated with severe pharyngeal infection may encroach on the airways, especially if there is peritonsillar or retropharyngeal abscess formation.

Answer 21

- More common in school-aged children and adolescents, but can occur in younger children and adults. - Clinical features include abrupt onset of symptoms, fever (above 38°C), tender cervical lymphadenopathy, tonsillar exudate, and the absence of cough, rhinorrhoea or nasal congestion.

Answer 22

1. Trismus 2. Drooling 3. Asymmetric tonsils 4. Displaced uvula 5. Unilateral facial swelling 6. Muffled or “hot potato” voice 7. Clinical features of sepsis 8. Immunosuppression Trismus and change in voice quality indicate the formation of potentially life-threatening peritonsillar abscess!

Answer 23

**Clinical evaluation** - Assess for clinical features of acute bacterial tonsillopharyngitis, acute viral tonsillopharyngitis, and differential diagnoses of acute tonsillopharyngitis. - Proceed to immediate treatment if red flags for tonsillopharyngitis or clinical features of airway compromise are present. - Routine testing for GAS is not recommended for children < 3 years old, as their prevalence of GAS pharyngitis and risk of developing subsequent acute rheumatic fever are both low. Consider testing only if specific risk factors (e.g., close household contact) are present. - Testing for GAS infection is not recommended in patients with clinical features that strongly suggest acute viral tonsillopharyngitis.

Answer 24

**Throat culture** **Indications** 1. Confirmatory test to definitively rule out GAS infection in symptomatic children and adolescents with a negative RADT 2. Recurrent or chronic tonsillitis **Findings**: Causative bacteria and their antibiotic susceptibility **Time to result**: 24–48 hours

Answer 25

= A set of criteria used to estimate the probability that pharyngitis is streptococcal (i.e., caused by group A Streptococcus). - **Rationale**: Estimate the likelihood of acute bacterial pharyngitis based on clinical features alone. - Clinical scoring systems cannot replace RADT or throat culture to make the diagnosis of GAS pharyngitis due to a lack of accuracy. - **Clinical applications**: Identifying patients with a low likelihood of GAS infection, thereby minimizing unnecessary diagnostic tests and antibiotic therapy. The use of scoring systems to identify patients with a high likelihood of bacterial pharyngitis in order to treat empirically without testing is controversial.

Answer 26

**Supportive care** - Ensure adequate hydration. - Consider household remedies such as salt-water gargles. - Consider oral topical local anesthetics: e.g., benzocaine lozenges, phenol throat sprays, compounded mouthwash. - Analgesics and antipyretics Amoxicillin therapy in patients with infectious mononucleosis can trigger a maculopapular and/or morbilliform rash. Reserve antibiotics for patients with confirmed bacterial tonsillopharyngitis (e.g., positive rapid strep test or throat culture), whenever possible. Avoid aspirin in children due to the risk of Reye syndrome.

Answer 27

- Antibiotic therapy for GAS pharyngitis can decrease the risk of rheumatic fever but does not affect the risk of PSGN. - Streptococcus "ph"yogenes is the most common cause of bacterial pharyngitis, which can result in rheumatic "phever" and poststreptococcal glomerulonephritis. - Rheumatic fever occurs in ∼ 3% of untreated cases of GAS infection.

Answer 28

**HSV related diseases** 1. Herpes labialis (cold sores) 2. Genital herpes (herpes genitalis) 3. Herpetic gingivostomatitis 4. Eczema herpeticum 5. Herpetic whitlow

Answer 29

**Distribution** - Most cases of malaria occur in tropical Africa (West and Central Africa). - Transmission also occurs in other tropical and subtropical regions such as South and Southeast Asia, and Central and South America.

Answer 30

Impaired consciousness, shock, and abnormal bleeding are signs of severe malaria that requires immediate IV treatment.

Answer 31

**Routine laboratory studies** 1) **CBC**: Changes in multiple parameters may occur. - Hemolytic anemia: ↓ Hb, ↓ haptoglobin, ↑ LDH, ↑ indirect bilirubin, ↑ reticulocytes - Thrombocytopenia - Leukocytosis or leukopenia are uncommon except in severe disease. 2) **CMP**: Hypoglycemia can occur in severe malaria. 3) **Urinalysis**: Hemoglobinuria may occur with intravascular hemolysis.

Answer 32

**Description**: potentially fatal manifestation or complication of malaria **Aetiology**: most commonly a result of falciparum malaria **Pathophysiology**: Infected erythrocytes occlude capillaries, which can lead to severe organ dysfunction.

Answer 33

**Approach** 1. Check for criteria for severe malaria. 2. Treat severe malaria immediately with IV artesunate. 3. Treat uncomplicated malaria based on species, resistance patterns, and degree of chemoprophylaxis. 4. Report all confirmed malaria to public health authorities.

Answer 34

**Treatment of uncomplicated malaria** Agent selection based on: 1. Infecting Plasmodium species 2. Prior use of chemoprophylaxis 3. Likelihood of chloroquine-resistance **Additional considerations in P. vivax and P. ovale** 1. Check G6PD activity levels. 2. Give primaquine or tafenoquine to eradicate hypnozoites dormant in hepatocytes.

Answer 35

All people ≥6 months of age are recommended to receive annual influenza vaccine. **Efficacy** - While vaccine effectiveness (VE) can vary, recent studies show that flu vaccination reduces the risk of flu illness by between 40% and 60% among the overall population during seasons when most circulating flu viruses are well-matched to those used to make flu vaccines. In general, influenza vaccine effectiveness has been found to vary between 30-60%. This implies that, on average, a vaccinated person is 30-60% less likely to experience the outcome being measured (e.g. influenza leading to attendance at a general practice or hospitalisation) than an unvaccinated person.

Answer 36

The Australian Immunisation Handbook recommends pneumococcal vaccination for specific groups including: 1. routine vaccination in infants and children 2. non-Indigenous adults aged 70 years and over 3. Aboriginal and Torres Strait Islander adults aged 50 years and over 4. children, adolescents and adults with risk conditions for pneumococcal disease

Answer 37

Acute HIV seroconversion refers to the initial phase of HIV infection when the body starts producing detectable antibodies against the virus. During this phase, individuals may experience a variety of symptoms and signs, which can resemble those of other viral illnesses. It's important to note that not everyone who acquires HIV infection will experience symptoms during seroconversion, and the presence or absence of symptoms cannot be used to conclusively diagnose HIV. **General considerations** - There are no clinical features specific to HIV infection. - In early HIV infection, patients are often asymptomatic. - Incubation period: usually 2–4 weeks - Infectiousness: two peaks (1st peak: within the first months after infection; 2nd peak: during AIDS-stage)

Answer 38

There are several tests used for the detection and diagnosis of HIV infection. These tests are designed to detect antibodies, antigens, or genetic material (RNA or DNA) related to the HIV virus.

Answer 39

**Approach** Order both nontreponemal tests and treponemal tests for: 1. Patients with clinical features of syphilis 2. Individuals with risk factors for syphilis infection 3. Pregnant individuals at the first prenatal visit 4. Order direct detection in patients with suitable skin lesions, e.g., exudative chancre, condyloma. 5. Consider additional studies (e.g., lumbar puncture) based on the clinical assessment.

Answer 40

False-Positive results on VDRL with Pregnancy, Viral infection (e.g., EBV, hepatitis), Drugs (e.g., chlorpromazine, procainamide), Rheumatic fever (rare), Lupus, and Leprosy

Answer 41

In general, water-soluble kidneys are excreted by the kidneys.

Answer 42

Pharmaceutical = Reactions between chemical constituents – eg. Binding agents – not so common with oral meds (exception = iron supplements, iron will bind to tetracycline, give not with other meds).

Answer 43

- Iron supplements = dark stools & constipation --> Take every other day - Cholestyramine = not commonly used but good for statin intolerant patients for lipid lowering - Opiates = delayed gastric emptying --> Therefore, don’t bother with oral meds after because most need gastric emptying before small bowel absorption (except aspirin, get absorbed across stomach wall). - Need Gastric pH to absorb iron therefore people on PPIs can become iron deficient.

Answer 44

More of a theoretical issue

Answer 45

- **Phase I** = trying to make the more lipid-solube drug more polar - Where you see most of the interactions – eg. Cytochrome P450 system most commonly implicated. - **Phase II** = conjugation (eg. Glucoronate – helps with excretion) - Drug interactions are most significant when they have a low therapeutic index – ie. If there is a bit more induction then it becomes toxic, no longer at a therapeutic dose – eg. Warfarin (low dose = ineffective but too high = bleeding). - Antibiotics + Warfarin - Antibiotics = usually sick so affects diet but also changes gut flora which influenced Vitamin K bioavailability.

Answer 46

2D6 and 3A4 = interact with some antipsychotic and antidepressants – has come up in exams!! Genetic screening test = tests for the levels of cytokines so you can adjust your meds.

Answer 47

NSAIDs = change prostaglandin metabolism, prostaglandin balance is important for renal medullary blood flow – where lots of tubular absorption and excretion takes place.

Answer 48

**Documentation of Prescription** - Communicates the prescription between medical, nursing, and pharmacy - Acts as a legal record of medical administration

Answer 49

TPN = Total Parental Nutrition

Answer 50

Adverse drug reactions (ADRs) are unwanted and harmful effects that occur as a result of medication use. In hospital medical practice, several factors contribute to the occurrence of ADRs. Here are some of the commonest causes of ADRs seen in hospitals:

Answer 51

1. Warfarin and Antibiotics 2. Simvastatin and Macrolide Antibiotics 3. Digoxin and Verapamil 4. Statins and Cyclosporine 5. Proton Pump Inhibitors (PPIs) and Clopidogrel 6. Monoamine Oxidase Inhibitors (MAOIs) and Serotoninergic Medications

Infectious Diseases & Adverse Drug Reactions Flashcards

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