Clinical Reasoning: Rapidly Progressive Dementia in a Man with HIV Infection and Undetectable Plasma Viral Load

Neurocognitive decline associated with HIV infection remains prevalent even in the antiretroviral therapy (ART) era, albeit usually in less severe forms. The differential diagnosis of cognitive impairment in this population is quite broad, including infectious causes such as CNS opportunistic infections, causes directly related to HIV such as HIV-associated neurocognitive disorders, and causes entirely unrelated to HIV infection such as primary dementia syndromes. In this case report, a 47-year-old man with HIV on ART with an undetectable plasma viral load presented with rapidly progressive dementia to a clinic in Zambia. He had been functioning independently and fully employed before symptom onset but had to stop working within 2 months of symptom onset because of the severity and rapidity of his cognitive decline. Initial workup led to an empiric diagnosis and initiation of an empiric treatment regimen, which was ultimately ineffective. This prompted re-evaluation, additional workup, and, ultimately, discovering the correct diagnosis. This case highlights the stepwise approach to developing a diagnosis in a resource-limited setting where there exists a high burden of HIV infection, including the necessity of empiric diagnoses of treatment plans when investigations are limited and the importance of reconsidering these diagnoses in the face of additional clinical information. In addition, it highlights both infectious and noninfectious causes of cognitive decline in people with HIV.