Mycology/Parasitology USMLE Step 1 Practice Question
A 52-year-old immunocompromised patient on long-term corticosteroids presents with progressive dyspnea and productive cough. Vital signs show BP 128/76, HR 102, RR 22, Temp 38.2°C, SpO2 88% on room air. Chest CT reveals multiple cavitary lesions in bilateral upper lobes. Sputum culture grows septate hyphae with acute-angle branching. Serum galactomannan antigen is negative. Which additional feature would confirm the diagnosis?
Answer choices
- AEndospores visible on smear
- BIndia ink staining positive
- CCryptococcal antigen in CSF
- DAspergillus galactomannan antigen detection in serumCorrect answer
- ECoccidioidal complement fixation antibodies
- FHistoplasma polysaccharide antigen in urine
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.