AIDS
introduction
AIDS is diagnosed when the immune system of a person infected with HIV becomes severely compromised (measured by CD4 cell count) and⁄or the person becomes ill with an opportunistic infection or illness.
without treatment, AIDS usually develops 8 to 10 years after initial HIV infection;
with early HIV diagnosis and treatment, this may be delayed by many years.
the 1st documented case in Australia is thought to be
Harvey, a 72yr old Sydney man who had never traveled overseas and became ill in Feb 1981 was later diagnosed with pneumocystis pneumonia which killed him by Sept 1981 - further tests in the 1990s showed he did indeed have HIV.
1)
HIV stages
in 2008 the CDC moved towards a HIV staging model to classify the disease
2):
HIV infection, stage 1:
HIV infection, stage 2:
HIV infection, stage 3 (AIDS):
HIV infection, stage unknown:
AIDS definition
adults and adolescents
CD4+ T-cell count below 200 cells/µl
OR
CD4+ T-cell percentage of total lymphocytes of less than 14%
OR
presence of an AIDS-defining illness in a person with HIV infection
Documentation of an AIDS-defining condition supersedes a CD4+ T-lymphocyte count of >200 cells/µL and a CD4+ T-lymphocyte percentage of total lymphocytes of >14.
children 18 months to 13 years
Criteria for HIV Infection:
Children aged 18 months to <13 years are categorized as HIV infected for surveillance purposes if at least one of laboratory criteria or the other criterion is met.
Criteria for AIDS:
Children aged 18 months to <13 years are categorized for surveillance purposes as having AIDS if the criteria for HIV infection are met and at least one of the AIDS-defining conditions has been documented
see http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5710a1.htm
children under 18 months age
Criteria for Definitive or Presumptive HIV Infection:
A child aged <18 months is categorized for surveillance purposes as definitively or presumptively HIV infected if born to an HIV-infected mother and if the laboratory criterion or at least one of the other criteria is met.
see http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5710a1.htm
AIDS-defining conditions
The following is from the CDC (2008)3):
Bacterial infections, multiple or recurrent%
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Cytomegalovirus disease (other than liver, spleen, or nodes), onset at age >1 month
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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%†
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Lymphoma, immunoblastic (or equivalent term)
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Mycobacterium avium complex or Mycobacterium kansasii, disseminated or extrapulmonary†
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Mycobacterium, other species or unidentified species, disseminated† or extrapulmonary†
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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].)