The epidemic of HIV infection that began in the late twentieth century has become one of the dominant health issues worldwide for the early twenty-first century. In the developed world, advances in the treatment of HIV infection have dramatically extended the lifespan of infected patients. As a result of these therapeutic advances, deaths from HIV infection in the USA fell by over 50% between 1995 and 2000. In developing areas of the world, HIV continues to spread among sexually active adults and their offspring. In some areas of Africa as much as 20% of the adult population is infected. HIV infection rates are also accelerating in the developed nations of Asia, and in areas of the former Soviet Union. The combined effects of increased longevity and accelerated worldwide dissemination are likely to result in increasing opportunities for internists and surgeons to collaborate in the management of HIV-infected patients.

The clinical course of HIV infection has been well described and should be familiar to most general internists. HIV infection is associated with abnormalities in the number and function of CD4 positive T-lymphocytes. Because the CD4 positive lymphocytes are essential to the regulation of the human immune system, progressive immune dysfunction is a natural consequence of HIV infection in most patients. This progressive immune dysregulation is associated with decreased cell-mediated immune function, alterations in the humoral immune response, chronic inflammation and depressed mucosal immunity.