A 30-year-old male with HIV presents with a severe headache and confusion. He reports that his headache started two weeks ago and has progressively worsened. His partner also mentions that he has had a low-grade fever and night sweats. He has been on antiretroviral therapy but his last CD4 count was low. What are the potential causes, and what are the next steps?
Given this patient's HIV status, low CD4 count, and presenting symptoms, a key concern is opportunistic infections including CNS tuberculosis. Other considerations could be toxoplasmosis, cryptococcal meningitis, or primary CNS lymphoma. The next steps would be to perform a lumbar puncture for cerebrospinal fluid analysis and to start empiric therapy for likely pathogens, including TB. A CT or MRI of the head may be required to look for focal lesions and rule out space-occupying lesions before performing a lumbar puncture.