Opportunistic viral infections in the setting of human immunodeficiency virus.

Human immunodeficiency virus (HIV) infection has provided a setting in which additional neurologic problems develop. The mechanism of these complications varies from agent to agent, but the added spectrum of diseases encountered has challenged diagnosticians and provided unparalleled opportunities to develop a deeper understanding of these conditions and their treatments. This review addresses the most prominent viral-associated complications, except for progressive multifocal leukoencephalopathy, which is addressed in a separate review. The complications of greatest importance both due to their frequency and severity are caused by cytomegalovirus, so these are discussed in greater depth. However, the association of Epstein-Barr virus with induction of central nervous system lymphoma represents an important viral linked complication of great importance. In addition, the increased activity of varicella zoster virus has been notable in the setting of HIV. Finally, human herpesvirus type 6 is an emerging virus of interest that has been identified in the setting of HIV infection, whose role in pathophysiology is only now being investigated.