infectious diseases
Human Immunodeficiency Virus (HIV) Infection
Key Points
HIV infects CD4+ lymphocytes and thus interferes with cell-mediated and, to a lesser extent, humoral immunity. HIV is spread mainly by sexual contact, parenteral exposure to contaminated blood or transplanted tissue or organs, and vertical transmission (in utero, during childbirth, or through breastfeeding). Frequent viral mutations combined with immune system damage significantly impair the body's ability to clear the HIV infection. Various opportunistic infections and cancers can develop and are the usual cause of death in untreated patients. Diagnose using antibody tests, and monitor by measuring viral load and CD4 count. Treat with a combination of antiretroviral drugs, which can restore immune function to nearly normal in most patients if they take the drugs consistently. Periodically counsel patients living with HIV about safer sex. Use postexposure and preexposure antiretroviral prophylaxis when indicated. Give primary prophylaxis against opportunistic infections based on the CD4 count. 