Infectious disease Flashcards
What is the typical pH in bacterial vaginosis
Usually > 4.5
EG more basic
Treatment of bacterial vaginosis
Metronidazole 400mg BD for 7 days or a once off 2g (if concerns for adherence)
Which antiretroviral is most likely to cause anaemia and what is the mechanism?
Zidovudine
Mechanism is via bone marrow suppression ( ie reduced formation of erythrocytes)
Note: usually a macrocytic anaemia
Meningitis with brain stem involvement what organism?
Listeria
NB also think listeria in immunosuppressed pts
Recommendations for influenza prophylaxis
Prophylaxis with oseltamivir within 48 hours of close contact with a patient infected with influenza for high risk patient
In a pt w/a new dx of both HIV and active Hep B what is the mgmt?
Start on antiretroviral regime that will also treat Hep B ( tenofovir or lamivudine)
Hep B prophylaxis in a pt with new dx HIV but hep B negative?
Hep B vaccination with double strength vaccine
Note: at either 0, 1, 6 months or 0, 2, 12 months
A pt with TB is diagnosed with HIV - considerations for antiretrovirals
- Avoid: ritonavir ( increases rifampin) and nevirapine (decreases rifampin)
- Include efavirenz - little effect on plasma levels rifampin
Which HIV med is nephrotoxic
Tenofovir is likely to cause nephrotoxicity.
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?
Brucellosis
Note: can be acute, chronic or symptoms
Less commonly can cause pneumonia, septic arthritis, infective endocarditis, jaundice
Diagnosis of Brucellosis
Clinical features + lab confirmation (blood cultures can take up to 6 weeks to grow)
Features of Q fever
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.
Diagnosis Q fever
Antibody titre to Coxiella burnetti (IgG and/or IgA) greater than 1:200
Catalase and coagulase positive/negative in S aureus
Both positive
Gomori’s methanamine silver stains for what?
Fungi
Tx of cutaneous larva migrans
Oral ivermectin in a single dose of 200 µg/kg body weight
Main use of Terbinafine
Tinea
What is the most common space occupying lesion in HIV/AIDS
Toxoplasmosis
Note: second is primary CNS lymphoma.Tuberculoma is common depending on the prevalence of tuberculosis.
Where is toxoplasmosis lesion in brain typically found vs CNS lymphoma
Toxo: basal ganglia and the corticomedullary junction
CNS lymphoma:deep white matter of the cortex
A positive rubella haemagglutination inhibition (HAI) combined with a negative rubella IgM is consistent with __
- Prior vaccination
- Prior infection
- Early acute infection
Typical timeline for HIV seroconversion
2 to 12 weeks following exposure to HIV
How to differentiate HIV seroconversion from glandular fever?
Seroconversion: pharyngitis is more severe and presents with maculopapular rash
Only rash in glandular fever if ampicillin given
Prophylaxis against meningococcal infection
Ciprofloxacin 1st line
NB does not interfere with OCP
Note: rifampacin would work but interferes with OCP
Definitive diagnosis of PCP pneumonia
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.
Drug of choice for Salmonella typhi.
Ciprofloxacin
Or azithryomycin (esp if south east asian travel)
Treatment of gonorrhoea infection vs chlamydia
Simple gonorrhoea: azithromycin
Disseminated gonorrhoea (such as arthritis) : CTX
Chlamydia: doxycycline
Side effects of isoniazid
Hepatitis
Peripheral neuritis (pyridoxine given prophylactically)
SLE like syndrome
Tx of MSSA endocarditis of native valve?
Flucloxacillin 2 g IV six times daily
Findings on imaging in HIV encephalopathy
Usually limited to cerebral atrophy
What is the most widely used method for C diff diagnosis?
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.
Which malaria prophylaxis is C/I in patients with hx of mental illness?
Mefloquine
Sulfadoxine-pyrimethamine is commonly used malaria prophylaxis T/F
F
Not used due to high levels of resistance.
If area with low levels of resistance use doxycycline
If high levels use malorone
Recurrent attacks of genital herpes tend to be more or less severe
Less severe
Also tend to be shorter
Transmission of genital herpes can occur in the absence of lesions T/F
T
Lamivudine is associated with rhabdomyolysis T/F
F
Note: Zidovudine is assoc with rhabdo though
Gonorrhoea morphology
Gram negative intracellular diplococci
What is the MAO of MRSA
Modification of target penicillin-binding proteins
Diabetic pt with cellulitis, most likely organism?
Group B strep
Note: overall in anyone commonest cause is strep and s aureus
Bisphosphonates should be given routinely to patients with myeloma, even in the absence of hypercalcaemia.
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
A pt on long term steroids is to start on tx for TB, hence the dose of steroids needs to be ___
Increased
Note: rifampicin increases metabolism of steroids
Tx of suspected nec fasc
Clindamycin and Tazocin
Note: typically due to group A strep
