AIDS



AIDS





Dementia, myelopathy due to HIV infection are AIDS-defining illnesses.


CNS Pathogenesis

HIV enters CNS in primary infection. May produce no symptoms, acute self-limited syndrome, or chronic disorder.



  • Possible causes: HIV itself, secondary opportunistic infections or neoplasia, metabolic abnormalities, complications of drug therapy, nutritional.


  • CNS invasion and injury: mechanism not known. In brain, virus infects only microglial cells and macrophages, not neurons, although designated “neurotropic virus” because neurologic disorders are frequent.

Neurologic disorders affect 70% of patients with AIDS; first manifestation of AIDS in 10–20%.


Clinical Syndromes


HIV-related Neurologic Syndromes in Early Infection

Indistinguishable from CNS infection by other viruses: aseptic meningitis, encephalopathy, leukoencephalitis, seizures, transverse myelitis, cranial or peripheral neuropathy, polymyositis, myoglobinuria. Course self-limited, often full neurologic recovery.

CSF abnormalities (pleocytosis up to 200 cells/mm3, oligoclonal bands) differentiate HIV from postinfectious disorders. HIV antibody test sometimes negative because symptoms may precede seroconversion by weeks. Consider p24 antigen and viral load assay if serology negative.



HIV-Related Neurologic Syndromes in Chronic Infection


AIDS Dementia Complex (ADC)

Other terms: HIV encephalitis, HIV encephalopathy.

Severe dementia, behavioral changes; motor disorder. Myelopathy and peripheral neuropathy in 25%. In HIV-positive people, these syndromes are diagnostic of AIDS.

Usually progressive; may be static.


Symptoms



  • Early: apathy, social withdrawal, diminished libido, slow thinking, poor concentration, forgetful. Psychiatric syndromes: psychosis, depression, mania.


  • Motor signs: slow movements, leg weakness, gait ataxia.


  • Advanced stage: akinetic mutism; immobile; global cognitive impairment, urinary incontinence.


  • Encephalopathy in children: may be static or progressive. Intellectual deterioration, microcephaly, delayed developmental milestones; pseudobulbar palsy; spastic quadriparesis (see also Chapter 168).


Investigations



  • CSF: normal or mild pleocytosis, high protein content, oligoclonal bands.


  • CT, MRI: Adults: cerebral atrophy, leukoencephalopathy. Children: also basal ganglia calcification. Pathology: microglial nodules, giant cells, focal perivascular demyelination, gliosis, neuronal loss in frontal cortex. Severity of pathology not always correlated with severity of dementia.


Treatment

Zidovudine (AZT), selegiline, nimodipine: mixed results. Improve, slow dementia, or no effect.

Predictors of dementia: CD4+ count <100 cell/μL, anemia, or AIDS-defining infection or neoplasm (19% to 25% risk in 2 years).

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Jul 27, 2016 | Posted by in NEUROLOGY | Comments Off on AIDS

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