Fungal and Parasitic Infections USMLE Step 1 Practice Question
A 34-year-old man with HIV infection presents to the emergency department with a 2-week history of fever, progressive headache, and neck stiffness. He has not taken antiretroviral therapy for 6 months. Vital signs are notable for temperature 39.2°C, blood pressure 110/68 mmHg, heart rate 102/min, and respiratory rate 18/min. Physical examination reveals nuchal rigidity but no focal neurologic deficits or rash. Laboratory studies show CD4 count of 18 cells/μL and serum cryptococcal antigen positive. Lumbar puncture is performed with cerebrospinal fluid (CSF) analysis revealing: protein 180 mg/dL, glucose 28 mg/dL, opening pressure 32 cm H2O, and white blood cell count 50/μL (mostly lymphocytes). India ink preparation of the CSF demonstrates round, encapsulated yeast. Which of the following is the most likely diagnosis?
Answer choices
- ATuberculous meningitis with CSF tuberculostasis
- BToxoplasmic encephalitis with secondary meningitis
- CCryptococcal meningitisCorrect answer
- DBacterial meningitis caused by Listeria monocytogenes
- ECoccidioidal meningitis with pulmonary involvement
- FCytomegalovirus ventriculoencephalitis
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