The complications of HIV-related infections and neoplasms affect virtually every organ. The general approach to the people living with HIV with symptoms is to evaluate the organ systems involved, aiming to diagnose treatable conditions rapidly. As shown in Figure 31–1, the CD4 lymphocyte count level enables the clinician to focus on the diagnoses most likely to be seen at each stage of immunodeficiency. Certain infections may occur at any CD4 count, while others rarely occur unless the CD4 lymphocyte count has dropped below a certain level. For example, a patient with a CD4 count of 600 cells/mcL, cough, and fever may have a bacterial pneumonia but would be very unlikely to have Pneumocystis jirovecii pneumonia.
Relationship of CD4 count to development of opportunistic infections. MAC, Mycobacterium avium complex; CMV, cytomegalovirus.
Many individuals living with HIV infection remain asymptomatic for years even without ART, with a mean time of approximately 10 years between infection and development of AIDS. When symptoms occur, they may be remarkably protean and nonspecific. Since virtually all the findings may be seen with other diseases, a combination of complaints is more suggestive of HIV infection than any one symptom.
Physical examination may be entirely normal. Abnormal findings range from completely nonspecific to highly specific for HIV infection. Some opportunistic infections specific for HIV infection include oral hairy leukoplakia of the tongue, disseminated Kaposi sarcoma, and cutaneous bacillary angiomatosis. Generalized lymphadenopathy, which is nonspecific, is common early in infection.
The specific presentations and management of the various complications of HIV infection are discussed under the Complications section below.
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Specific tests for HIV include antibody, antigen, and viral load detection (Table 31–2). Initial testing for HIV should be done using a fourth-generation HIV antigen/antibody immunoassay. It detects HIV-1 and HIV-2 antibodies and HIV-1 p24 antigen. Reactive specimens are then tested with an HIV-1/HIV-2 differentiation immunoassay to confirm infection and to distinguish HIV-1 from HIV-2. For patients who are reactive on both tests, the sensitivity and specificity for chronic HIV approach 100%. Patients who have a reactive HIV antigen/antibody immunoassay but a negative HIV-1/HIV-2 differentiation immunoassay should have a HIV-1 viral load test (nucleic acid test); those with positive viral loads despite a negative differentiation assay are likely having acute HIV infection. Persons who are reactive on the initial test ...