The complications of HIV-related infections and neoplasms affect virtually every organ. The general approach to the HIV-infected person with symptoms is to evaluate the organ systems involved, aiming to diagnose treatable conditions rapidly. As can be seen in Figure 31–1, the CD4 lymphocyte count result 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 pneumonia.
Relationship of CD4 count to development of opportunistic infections. MAC, Mycobacterium avium complex; CMV, cytomegalovirus; CNS, central nervous system.
Many individuals with HIV infection remain asymptomatic for years even without antiretroviral treatment, 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. Those that are specific for HIV infection include hairy leukoplakia of the tongue, disseminated Kaposi sarcoma, and cutaneous bacillary angiomatosis. Generalized lymphadenopathy is common early in infection.
The specific presentations and management of the various complications of HIV infection are discussed under the Complications section below.
et al. Primary HIV infection: clinical presentation, testing, and treatment. Curr Infect Dis Rep. 2017 Sep 7; 19(10):37.
Specific tests for HIV include antibody and antigen detection (Table 31–2). Conventional HIV antibody testing is done by ELISA. Positive specimens are then confirmed by a different method (eg, Western blot). The sensitivity of screening serologic tests is greater than 99.9%. The specificity of positive results by two different techniques approaches 100% even in low-risk populations. False-positive screening tests may occur as normal biologic variants or in association with recent influenza vaccination or other disease states, such as connective tissue disease. These are usually detected by negative confirmatory tests. Antibodies will be detectable with current screening serologic tests in 95% of persons within 6 weeks after infection.
Table 31–2.Laboratory findings with HIV infection. ||Download (.pdf) Table 31–2. Laboratory findings with HIV infection.
|Test ||Significance |
|HIV enzyme-linked immunosorbent assay (ELISA) ||Screening test for HIV infection. Of ELISA tests 50% are positive within 22 days after HIV transmission; 95% are positive within 6 weeks ...|