VII. HIV-Associated CNS disorders
A. Pathologic Changes due directly to HIV infection (cont):
1. The virus enters the brain, probablyprimarily by way of macrophages, as HIV has been localized in CNS, mainly in macrophages, microglia and multinucleated giant cells.The virus is able to reproduce in the brain.
2. Vacuolar myelopathy is sometimes seen in the spinal cord. This change consists of white matter vacuolation in posterior and lateral columns, and is mainly due to swelling within myelin sheaths.
B. Secondary Effects of Immune Suppression:
Opportunistic infections. In addition to HIV infection, opportunistic viral infection of the brain is a relatively frequent complication of HIV-related immunosuppression. A variety of viruses and fungi, have been identified, primarily cytomegalovirus, cryptococcus, and toxoplasma. These infecting agents can be isolated from the brains of about 25% of AIDS patients. Other secondary effects include increased incidence of primary CNS lymphoma and progressive multifocal leukoencephalopathy (PML)