# HIV Neurology

> HIV neurology for NEET-SS Neurology: HAND spectrum, distal sensory polyneuropathy, opportunistic infections by CD4 count and immune reconstitution syndrome.

- Canonical URL: https://prepelephant.com/topics/neet-ss/neurology/hiv-neurology
- Exam / course: NEET-SS · Subject: Neurology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "HIV Neurology", PrepElephant, https://prepelephant.com/topics/neet-ss/neurology/hiv-neurology

## Direct answer

Neurological disease in HIV comes from the virus itself, from opportunists arriving on schedule with falling CD4 counts, and from antiretroviral toxicity and immune reconstitution. HIV-associated neurocognitive disorder spans asymptomatic impairment to dementia with subcortical features, and distal sensory polyneuropathy is the commonest manifestation. The CD4 count organises the opportunists: toxoplasmosis and cryptococcal meningitis below 100 cells, progressive multifocal leukoencephalopathy at low counts, and cytomegalovirus disease below 50 — with primary central nervous system lymphoma alongside and immune reconstitution after antiretroviral initiation.

## What you must remember

- HIV-associated neurocognitive disorder: subcortical cognitive slowing; diagnose by excluding opportunists, depression, intoxication and antiretroviral neurotoxicity; rarer in the antiretroviral era but not absent.
- Distal sensory polyneuropathy: painful stocking-distribution paraesthesiae with absent ankle jerks, from the virus or older antiretrovirals such as stavudine, still encountered in places.
- Cerebral toxoplasmosis: CD4 below 100 with multiple ring-enhancing lesions favouring basal ganglia; treat empirically with pyrimethamine, sulfadiazine and folinic acid — response within two weeks confirms clinically, non-response demands biopsy for lymphoma.
- Cryptococcal meningitis: India carries a large burden; CD4 below 100 with headache and raised pressure, positive antigen and India ink; World Health Organization 2022 guidance endorses single high-dose liposomal amphotericin with flucytosine and fluconazole for one week, with conventional amphotericin-based induction where liposomal drug or flucytosine is unavailable (flucytosine access in India remains variable); therapeutic lumbar punctures save lives; defer antiretrovirals four to six weeks.
- Progressive multifocal leukoencephalopathy: JC virus infection of oligodendrocytes producing non-enhancing white-matter lesions conforming to tracts, confirmed by CSF polymerase chain reaction; immune restoration is the main therapy.
- Cytomegalovirus below 50 cells: retinitis with floaters, lumbosacral radiculomyelopathy with ascending weakness and bladder involvement, and encephalitis; treated with ganciclovir, valganciclovir or foscarnet.
- Primary central nervous system lymphoma: Epstein-Barr-driven single or few deep enhancing lesions with supportive CSF polymerase chain reaction, treated with antiretrovirals plus oncology-directed therapy rather than steroids-first, which obscure the biopsy. Immune reconstitution inflammatory syndrome — paradoxical worsening weeks after antiretrovirals as immunity recovers, dominated by tuberculosis and cryptococcal variants in India — takes corticosteroids when severe while antiretrovirals usually continue.

## Common confusion

The ring-enhancing-lesion triad — toxoplasmosis, lymphoma, tuberculoma — is the recurring decision: toxoplasmosis is multiple and basal with prompt empirical-therapy response, lymphoma is fewer, larger and Epstein-Barr-positive, and tuberculoma travels with basal meningitis in India. Cryptococcal and tuberculous meningitis separate on antigen testing and India ink, not gestalt. Cognitive decline is not automatically dementia: depression, efavirenz toxicity and metabolic disease queue first. Immune reconstitution misread as treatment failure leads to blind switches instead of steroids with continued therapy.

## Exam-focused takeaway

Organise revision by CD4 strata — below 100 for toxoplasmosis and cryptococcus, below 50 for cytomegalovirus — and by the empiric-then-biopsy algorithm for mass lesions. The cryptococcal numbers carry marks: antiretroviral deferral of four to six weeks and therapeutic lumbar punctures for pressure. Expect an immune reconstitution stem answered by steroids with continued therapy, and a neurocognitive stem answered by exclusion.

## Frequently asked questions

### At what CD4 count does cryptococcal meningitis occur?

Usually below 100 cells per microlitre; headache in that range warrants antigen testing before it becomes an emergency.

### How is cerebral toxoplasmosis managed?

Empirical pyrimethamine with sulfadiazine and folinic acid; clinical and radiological response within two weeks confirms the diagnosis, non-response prompts biopsy.

### What causes progressive multifocal leukoencephalopathy?

Reactivation of JC virus infecting oligodendrocytes, producing non-enhancing demyelinating lesions; immune restoration is the mainstay of therapy.

### When should antiretrovirals start after cryptococcal meningitis?

After approximately four to six weeks of antifungal therapy, balancing fungal control against immune reconstitution risk.

### What is immune reconstitution inflammatory syndrome?

Paradoxical deterioration within weeks of starting antiretrovirals as immunity reacts to latent antigen, classically with tuberculosis and cryptococcus; corticosteroids when severe.