Neurologic manifestations of infection with human immunodeficiency virus. Clinical features and pathogenesis.

Subacute encephalitis caused by infection of the central nervous system by the human immunodeficiency virus (HIV) is the most frequent cause of neurologic dysfunction in patients with the acquired immunodeficiency syndrome (AIDS). This disorder results in progressive cognitive, motor, and behavioral abnormalities in at least two thirds of patients with AIDS. Pathologic evidence of subacute encephalitis is found in 90% of these patients at autopsy. Human immunodeficiency virus is also the etiologic agent of aseptic meningitis, a disease that can occur at the time of seroconversion. Other neurologic disorders frequently associated with HIV include peripheral neuropathies and vacuolar myelopathy. Thus, HIV is neurotropic and may enter the central nervous system early in the course of infection. Neurologic disease may be the only clinical manifestation of HIV infection. Although mechanisms of pathogenesis are unclear, cells of monocyte-macrophage lineage may be important in viral spread to and within the central nervous system. Effective antiviral therapy will probably require penetration of drugs across the blood-brain barrier.