VII. HIV-Associated CNS disorders
CNS involvement may occur due to primary effects of HIV infection or to secondary effects of immune suppression. Between 10 and 20% of HIV-infected patients present with neurologic signs as their first clinical manifestation of infection. In some, no other signs of AIDS develop. Between 50 and 70% of all AIDS patients eventually develop some features of what is called AIDS dementia or the AIDS-related cognitive-motor complex. This term is used to describe the characteristic pattern of cognitive, motor, and behavioral dysfunction, including mood disturbances, seen in AIDS patients. At autopsy, between 60 and 90% of AIDS patients' brains show some form of pathology.
A. Pathologic Changes due directly to HIV infection
1. The pathology associated with the AIDS-related cognitive-motor complex, sometimes called subacute encephalitis, is located mainly in subcortical areas, with relative sparing of cerebral cortex. Microscopic changes include:
diffuse white matter pallor
perivascular infiltrates of lymphocytes and macrophages
foci of necrosis, gliosis, and/or demyelination
microglial nodules, macrophages and multinucleated cells