Infectious disease

Question 1

What is the typical pH in bacterial vaginosis

Answer 1

Usually > 4.5

EG more basic

Question 2

Treatment of bacterial vaginosis

Answer 2

Metronidazole 400mg BD for 7 days or a once off 2g (if concerns for adherence)

Question 3

Which antiretroviral is most likely to cause anaemia and what is the mechanism?

Answer 3

Zidovudine

Mechanism is via bone marrow suppression ( ie reduced formation of erythrocytes)

Note: usually a macrocytic anaemia

Question 4

Meningitis with brain stem involvement what organism?

Answer 4

Listeria

NB also think listeria in immunosuppressed pts

Question 5

Recommendations for influenza prophylaxis

Answer 5

Prophylaxis with oseltamivir within 48 hours of close contact with a patient infected with influenza for high risk patient

Question 6

In a pt w/a new dx of both HIV and active Hep B what is the mgmt?

Answer 6

Start on antiretroviral regime that will also treat Hep B ( tenofovir or lamivudine)

Question 7

Hep B prophylaxis in a pt with new dx HIV but hep B negative?

Answer 7

Hep B vaccination with double strength vaccine

Note: at either 0, 1, 6 months or 0, 2, 12 months

Question 8

A pt with TB is diagnosed with HIV - considerations for antiretrovirals

Answer 8

1. Avoid: ritonavir ( increases rifampin) and nevirapine (decreases rifampin)
2. Include efavirenz - little effect on plasma levels rifampin

Question 9

Which HIV med is nephrotoxic

Answer 9

Tenofovir is likely to cause nephrotoxicity.

Question 10

Farmer presents with myalgia, fatigue and occasional fever and right knee pain for past 6 months. Found to have lymphadenopathy and hepatosplenomegally on exam. Likely diagnosis?

Answer 10

Brucellosis

Note: can be acute, chronic or symptoms
Less commonly can cause pneumonia, septic arthritis, infective endocarditis, jaundice

Question 11

Diagnosis of Brucellosis

Answer 11

Clinical features + lab confirmation (blood cultures can take up to 6 weeks to grow)

Question 12

Features of Q fever

Answer 12

Q fever is usually a self-limited respiratory illness Chronic infection may become established and can manifest as hepatitis, osteomyelitis or endocarditis.
Low-grade fever (or no fever), signs of heart failure, hepatosplenomegaly, clubbing, arterial emboli,leukocytoclastic vasculitic rash,
immune complex-mediated GN and arterial emboli.

Question 13

Diagnosis Q fever

Answer 13

Antibody titre to Coxiella burnetti (IgG and/or IgA) greater than 1:200

Question 14

Catalase and coagulase positive/negative in S aureus

Answer 14

Both positive

Question 15

Gomori’s methanamine silver stains for what?

Answer 15

Fungi

Question 16

Tx of cutaneous larva migrans

Answer 16

Oral ivermectin in a single dose of 200 µg/kg body weight

Question 17

Main use of Terbinafine

Answer 17

Tinea

Question 18

What is the most common space occupying lesion in HIV/AIDS

Answer 18

Toxoplasmosis

Note: second is primary CNS lymphoma.Tuberculoma is common depending on the prevalence of tuberculosis.

Question 19

Where is toxoplasmosis lesion in brain typically found vs CNS lymphoma

Answer 19

Toxo: basal ganglia and the corticomedullary junction

CNS lymphoma:deep white matter of the cortex

Question 20

A positive rubella haemagglutination inhibition (HAI) combined with a negative rubella IgM is consistent with __

Answer 20

1. Prior vaccination
2. Prior infection
3. Early acute infection

Question 21

Typical timeline for HIV seroconversion

Answer 21

2 to 12 weeks following exposure to HIV

Question 22

How to differentiate HIV seroconversion from glandular fever?

Answer 22

Seroconversion: pharyngitis is more severe and presents with maculopapular rash

Only rash in glandular fever if ampicillin given

Question 23

Prophylaxis against meningococcal infection

Answer 23

Ciprofloxacin 1st line
NB does not interfere with OCP

Note: rifampacin would work but interferes with OCP

Question 24

Definitive diagnosis of PCP pneumonia

Answer 24

Identification of the fungus by silver staining (with methenamine silver) or PCR amplification.

Occasionally found in induced sputum, however bronchoalveolar lavage increases the rate of diagnosis.

Question 25

Drug of choice for Salmonella typhi.

Answer 25

Ciprofloxacin

Or azithryomycin (esp if south east asian travel)

Question 26

Treatment of gonorrhoea infection vs chlamydia

Answer 26

Simple gonorrhoea: azithromycin
Disseminated gonorrhoea (such as arthritis) : CTX

Chlamydia: doxycycline

Question 27

Side effects of isoniazid

Answer 27

Hepatitis
Peripheral neuritis (pyridoxine given prophylactically)
SLE like syndrome

Question 28

Tx of MSSA endocarditis of native valve?

Answer 28

Flucloxacillin 2 g IV six times daily

Question 29

Findings on imaging in HIV encephalopathy

Answer 29

Usually limited to cerebral atrophy

Question 30

What is the most widely used method for C diff diagnosis?

Answer 30

Toxin detection

Note: ELISA tests are specific but not as sensitive. Culture is sensitive but often does not differentiate between toxigenic and non-toxigenic strains.

Question 31

Which malaria prophylaxis is C/I in patients with hx of mental illness?

Answer 31

Mefloquine

Question 32

Sulfadoxine-pyrimethamine is commonly used malaria prophylaxis T/F

Answer 32

F

Not used due to high levels of resistance.
If area with low levels of resistance use doxycycline
If high levels use malorone

Question 33

Recurrent attacks of genital herpes tend to be more or less severe

Answer 33

Less severe
Also tend to be shorter

Question 34

Transmission of genital herpes can occur in the absence of lesions T/F

Answer 34

T

Question 35

Lamivudine is associated with rhabdomyolysis T/F

Answer 35

F

Note: Zidovudine is assoc with rhabdo though

Question 36

Gonorrhoea morphology

Answer 36

Gram negative intracellular diplococci

Question 37

What is the MAO of MRSA

Answer 37

Modification of target penicillin-binding proteins

Question 38

Diabetic pt with cellulitis, most likely organism?

Answer 38

Group B strep

Note: overall in anyone commonest cause is strep and s aureus

Question 39

Bisphosphonates should be given routinely to patients with myeloma, even in the absence of hypercalcaemia.

Answer 39

T

Note: Biphosphonates reduce bony disease in myeloma, lowering the frequency of pathological fractures. There is also evidence that bisphosphonates modulate the disease and have some antitumour activity

Question 40

A pt on long term steroids is to start on tx for TB, hence the dose of steroids needs to be ___

Answer 40

Increased

Note: rifampicin increases metabolism of steroids

Question 41

Tx of suspected nec fasc

Answer 41

Clindamycin and Tazocin

Note: typically due to group A strep