Commonly known as
Causes
Pathophysiology
Over time, HIV infection depletes the population of T lymphocytes in the body of a host. Once the immune dysfunction has reached a certain level of severity, minor infections become life-threatening and entirely new infections can occur. This state of severe immune dysfunction is known as AIDS. At that point, the immune system is unable to mount a response significant enough to prevent pathogenesis of organisms with poor virulence and infectivity.
Diagnosis
A diagnosis of AIDS is made when a patient has an accurate laboratory result of:
- a CD4+ T-cell count below 200 cells/µL
- a CD4+ T-cell percentage of total lymphocytes of less than 14%
The diagnosis is also made by the presence of
AIDS-defining illnesses. These are diseases which only arise in patients with acquired immunodeficiency syndrome. This includes:
- Bacterial infections, multiple or recurrent*
- Candidiasis of bronchi, trachea, or lungs
- Candidiasis of esophagus†
- Cervical cancer, invasive§
- Coccidioidomycosis, disseminated or extrapulmonary
- Cryptococcosis, extrapulmonary
- Cryptosporidiosis, chronic intestinal (>1 month's duration)
- Cytomegalovirus disease (other than liver, spleen, or nodes), onset at age >1 month
- Cytomegalovirus retinitis (with loss of
vision)†
- Encephalopathy, HIV related
- Herpes simplex: chronic ulcers (>1 month's duration) or bronchitis, pneumonitis, or esophagitis (onset at age >1 month)
- Histoplasmosis, disseminated or extrapulmonary
- Isosporiasis, chronic intestinal (>1 month's duration)
- Kaposi sarcoma†
- Lymphoid interstitial pneumonia or pulmonary lymphoid hyperplasia
complex*†
- Lymphoma, Burkitt (or equivalent term)
- Lymphoma, immunoblastic (or equivalent term)
- Lymphoma, primary, of brain
- Mycobacterium avium complex or Mycobacterium
kansasii, disseminated or extrapulmonary†
- Mycobacterium tuberculosis of any site,
pulmonary,†§
disseminated,† or
extrapulmonary†
- Mycobacterium, other species or unidentified species,
disseminated† or
extrapulmonary†
- Pneumocystis jirovecii
pneumonia†
- Pneumonia, recurrent†§
- Progressive multifocal leukoencephalopathy
- Salmonella septicemia, recurrent
- Toxoplasmosis of brain, onset at age >1
month†
- Wasting syndrome attributed to HIV
* Only among children aged <13 years. (CDC. 1994 Revised
classification system for human immunodeficiency virus infection in
children less than 13 years of
age. MMWR 1994;43[No. RR-12].)
† Condition that might be diagnosed presumptively.
§ Only among adults and adolescents aged
>13 years. (CDC. 1993 Revised classification system for HIV infection and expanded surveillance case definition for
AIDS among adolescents and adults. MMWR 1992;41[No. RR-17].)
