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HIV-associated neurocognitive disorder — MRCPsych Paper A MCQ

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ModerateNeuropathologyHIV-associated neurocognitive disorderMRCPsych Paper A

A 45-year-old man with advanced untreated HIV develops progressive apathy, impaired attention, psychomotor slowing and a slowed gait over 6 months. His cognitive decline now interferes with everyday functioning. He has no fever, headache or focal neurological deficit. Which neuropathological finding would be most characteristic of the underlying disorder?

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Correct answer: E — Microglial nodules with multinucleated giant cells and white-matter injury

The answer is E. Advanced untreated HIV with a progressive subcortical pattern—apathy, impaired attention, psychomotor and gait slowing—suggests HIV-associated dementia. HIV encephalitis predominantly involves macrophages and microglia rather than direct productive infection of neurons. Characteristic findings include microglial nodules, multinucleated giant cells and inflammatory or degenerative white-matter injury. Option C describes progressive multifocal leukoencephalopathy, which is caused by JC virus and commonly produces focal neurological deficits. Option A is characteristic of Parkinson disease or dementia with Lewy bodies. Option B describes Alzheimer disease pathology, which is typically amnestic and cortical rather than a rapidly progressive subcortical syndrome in advanced HIV. Option D describes motor neuron disease and would not account for the cognitive-behavioural presentation.

Reference: Dos Reis RS et al. Microglial reactivity and nodule formation are associated with Synaptodendritic damage in the brains of people with HIV-1. Brain Pathology. 2026;36(3):e70064. https://pubmed.ncbi.nlm.nih.gov/41467330/