HIV AND NEUROLOGY

1. Primary HIV diseases – encephalopathy, neuropathy

2. 2^nd infections – toxo, crypto, PML

3. ART effects on neurological fxn.

PRIMARY DISEASES OF HIV

• Pirmary HIV encephalopathy – may or may not be clinically picked up during the initial HIV infection (often recalled within a hx of HIV) – headache +/- meningismus, may be mistaken for Mono. Usually encephalopathy clears, but may not in some patients, instead progressing and rarely being fatal.

• HIV encephalopathy aka AIDS Dementia Complex aka Late-Stage HIV encephalopathy –encephalopathic picture unique to HIV patients, now limited by HART to under 5% of HIV pts. Progressive memory and other problems, extreme apathy and indifference (not depressed) – may take a patient 30 seconds to respond to a simple question. Clinical assn. with myelopathy. Must rule out 2^nd infection and tumor.

• MRI reveals hydrocephalus ex vacuo (brain shrinkage). Use of PCR to rule out viral infection.

• Outlook much better post-HART.

• HIV does not enter but destroys neurons. HIV infects the macrophages that cross the BBB (Trojan horse); activate astrocytes to make toxic cytokines and generate an inflammatory response.

• Best tx involves keeping the CD4 counts as low as possible.

• HIV peripheral neuropathy – occurs in approximately 30% of all AIDS patients. May be clinically identical to G-B, necessitating HIV test in any presentation of G-B with any HIV risk factors. This demyelinating disease is the result of a disrupted immune system, with antibody and cytokine mediated nerve damage. Increased incidence of Bell’s palsy.

  • Tx includes steroids, plasma exchange, IV IG – usually self-limiting (months to years).

SECONDARY INFECTIONS

• Toxo, Crypto, PML are all covered well in the notes.

DRUGS

• Nucleoside analogs like ddI, ddC, or d4T may cause foot pain, serious toe pain secondary to the meds. Drug-induced neuropathies need to be realized soon because they can be made chronic if the drug is continued. Sometimes HIV pts need these drugs, and you are balancing the need for low CD4 count with the neuropathy induced by nucleoside analogs. Soft ground.

• Thalidomide and dapsone are AIDS-related meds that may cause neuropathy.

Category: Neurology notes