AIDS and Opportunistic Infections

Pulmonary parenchymal complications remain the main cause of morbidity and mortality in human immunodeficiency virus (HIV) infected patients (McGuinness, 1997). Early diagnosis and treatment of these complications are important to improve survival. HIV impairs the immune system, leading the infected person susceptible to a variety of infections, called opportunistic infections, a leading cause of mortality and morbidity in patients with HIV/AIDS. The effect of HIV on the immune system is monitored by measuring the CD4 (T-helper) lymphocyte count in the blood. Depletion of CD4 cell count is a hallmark of disease progression in AIDS. CD4 cell count is essential to decide about the timing of initiation of antiretroviral therapy and for prophylaxis of opportunistic infections. It has been known that the lungs are principal targets of HIV-associated complications and persons with HIV infection are at an increased risk for opportunistic pneumonias, neoplasms, and other pulmonary conditions. The spectrum of pulmonary manifestations in patients infected with HIV is broad, including many infectious and noninfectious complications. Pneumonia is the leading HIV-associated infection. In a recent report in which 762 patients with HIV/AIDS were analyzed, pulmonary infections was found as the most prevalent infections (Huang et al., 2010). It is estimated that 65% of the patients infected with HIV will present pulmonary involvement as their first clinical manifestation of the syndrome and that approximately 80% of these patients will present some kind of pulmonary involvement in the course of the disease (Suffredini & Masur, 1988). This section is related with the pulmonary infectious complications of HIV/AIDS.