Infectious Diseases Flashcards
7 cards from real Physician Assistant practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Infectious Diseases flashcards as text
At what CD4 count should primary prophylaxis against Pneumocystis jirovecii pneumonia be started in a patient with HIV?
Answer: Below 200 cells/mm³
PJP prophylaxis, usually with TMP-SMX, is indicated when the CD4 count falls below 200 cells/mm³ or with oropharyngeal candidiasis.
A patient with HIV and a CD4 count of 40 cells/mm³ has fever, weight loss, and diarrhea, and blood cultures grow acid-fast bacilli. What is the most likely organism?
Answer: Mycobacterium avium complex
Disseminated MAC typically occurs when CD4 is below 50 cells/mm³ and presents with fever, weight loss, diarrhea, and mycobacteremia.
A patient with AIDS has headache, fever, and elevated opening pressure on lumbar puncture, and India ink stain shows encapsulated yeast. What is the preferred induction therapy?
Answer: Amphotericin B plus flucytosine
Cryptococcal meningitis induction therapy is liposomal amphotericin B plus flucytosine, followed by fluconazole consolidation.
A patient with HIV has multiple ring-enhancing brain lesions and a positive Toxoplasma IgG. What is the first-line treatment?
Answer: Pyrimethamine, sulfadiazine, and leucovorin
CNS toxoplasmosis is treated with pyrimethamine plus sulfadiazine, with leucovorin given to prevent bone marrow suppression.
Which HLA allele must be tested for before starting abacavir?
Answer: HLA-B*57:01
HLA-B*57:01 carriers are at high risk for a severe abacavir hypersensitivity reaction, so the drug is contraindicated in them.
After a high-risk sexual exposure to HIV, within what time frame should post-exposure prophylaxis be started?
Answer: Within 72 hours
HIV PEP should begin as soon as possible and no later than 72 hours after exposure, and it is continued for 28 days.
A patient with AIDS and a CD4 count of 30 cells/mm³ reports painless floaters and vision loss, and fundoscopy shows hemorrhages with fluffy white retinal infiltrates. What is the most likely diagnosis?
Answer: CMV retinitis
CMV retinitis appears when CD4 is below 50 cells/mm³, with a 'pizza pie' or 'cottage cheese and ketchup' fundus.
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