21st November 2023

HIV

A decline in immune functioning due to HIV / AIDS can often result in irreversible brain damage. Neuropsychiatric symptoms such as depression, memory impairment, poor concentration and behavioural changes can be seen because of this.

These symptoms together constitute HIV associated neuropsychiatric disorder (HAND).

Before ART, 20-40% of people with HIV developed HAND.

HAND can present as the following:

• Asymptomatic neurocognitive impairment – Daily life unaffected.
• Mild neurocognitive disorder.
• HIV-associated dementia – After the widespread use of ART, this now presents as a milder form called minor cognitive motor disorder (MCMD).

Investigations to diagnose HAND:

• CSF analysis – Markers such as neopterin, chemokine MCP-1, axon neurofilament light chain protein and tau protein.
• Neuroimaging to exclude treatable conditions.

HIV Entry into the brain – Acute infection with HIV loosens the tight endothelial junctions constituting the blood brain barrier. The dysregulation of the blood brain barrier and infected monocytes might lead to HIV entry into the brain. HIV predominantly infects macrophages and microglia in the central nervous system.

Multinucleated giant cells can be seen, and these are thought to be infected monocytes.

A receptor called p75NTR may contribute to damaged synapses.

Opportunistic infections

The incidence of opportunistic infections in HIV increases greatly if CD4 counts are less than 200 cells/mm3.

The common causative agents are herpes simplex virus, cytomegalovirus, polyomavirus, toxoplasmosis, cryptococcus and candida albicans.

References

• Yakub, M., Harrison, J. (2021.). Neuropathology: Part 2 – Prions and HIV. Trainees Online (TrON). Available online at: https://elearninghub.rcpsych.ac.uk/product?catalog=05_TRON_Neuropath_p2 [Accessed April 2023]
• Ghafouri, M., Amini, S., Khalili, K., & Sawaya, B. E. (2006). HIV associated dementia: symptoms and causes. Retrovirology, 3(1), 28.