HIV/AIDS
From Wikipedia, the free encyclopedia
This article is about the disease. For the virus, see HIV. For other uses, see AIDS (disambiguation).
| HIV/AIDS | |
|---|---|
| |
| Classification and external resources | |
| Specialty | Infectious disease |
| ICD-10 | B20 – B24 |
| ICD-9-CM | 042-044 |
| OMIM | 609423 |
| DiseasesDB | 5938 |
| MedlinePlus | 000594 |
| eMedicine | emerg/253 |
| Patient UK | HIV/AIDS |
| MeSH | D000163 |
Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV).[2][3][4] Following initial infection, a person may experience a brief period of influenza-like illness. This is typically followed by a prolonged period without symptoms. As the infection progresses, it interferes more and more with the immune system, making the person much more susceptible to common infections, like tuberculosis, as well as opportunistic infections and tumors that do not usually affect people who have working immune systems. The late symptoms of the infection are referred to as AIDS. This stage is often complicated by an infection of the lung known as pneumocystis pneumonia,severe weight loss, skin lesions caused by Kaposi's sarcoma, or other AIDS-defining conditions.
HIV is transmitted primarily via unprotected sexual intercourse (includinganal and oral sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding.[5]Some bodily fluids, such as saliva and tears, do not transmit HIV.[6]Common methods of HIV/AIDS prevention include encouraging and practicing safe sex, needle-exchange programs, and treating those who are infected.[7] There is no cure or vaccine; however, antiretroviral treatmentcan slow the course of the disease and may lead to a near-normal life expectancy. While antiretroviral treatment reduces the risk of death and complications from the disease, these medications are expensive and have side effects. Without treatment, the average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype.[8]
Since its discovery, AIDS has caused an estimated 36 million deaths worldwide (as of 2012).[9] In 2013 it resulted in about 1.34 million deaths.[10] As of 2012, approximately 35.3 million people are living with HIV globally.[9] HIV/AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading.[11] Genetic research indicates that HIV originated in west-central Africa during the late 19th or early 20th century.[12] AIDS was first recognized by the United States Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade.[13]
HIV/AIDS has had a great im
has attracted international medical and political attention as well as large-scale funding since it was identified in the 1980s.[14]
pact on society, both as an illness and as a source of discrimination. The disease also has significant economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has become subject to many controversies involving r
Signs and symptoms
Main article: Signs and symptoms of HIV/AIDS
Acute infection
The initial period following the contraction of HIV is called acute HIV, primary HIV or acute retroviral syndrome.[15][17] Many individuals develop an influenza-like illness or a mononucleosis-like illness 2–4 weeks post exposure while others have no significant symptoms.[18][19] Symptoms occur in 40–90% of cases and most commonly include fever, large tender lymph nodes, throat inflammation, a rash, headache, and/or sores of the mouth and genitals.[17][19] The rash, which occurs in 20–50% of cases, presents itself on the trunk and is maculopapular, classically.[20] Some people also develop opportunistic infections at this stage.[17] Gastrointestinal symptoms such as nausea, vomiting ordiarrhea may occur, as may neurological symptoms of peripheral neuropathy or Guillain-Barre syndrome.[19] The duration of the symptoms varies, but is usually one or two weeks.[19]
Due to their nonspecific character, these symptoms are not oftenrecognized as signs of HIV infection. Even cases that do get seen by a family doctor or a hospital are often
misdiagnosed as one of the many common infectious diseases with overlapping symptoms. Thus, it is recommended that HIV be considered in people presenting an unexplained fever who may have risk factors for the infection.[19]
Clinical latency
The initial symptoms are followed by a stage called clinical latency, asymptomatic HIV, or chronic HIV.[16] Without treatment, this second stage of the natural history of HIV infection can last from about three years[21] to over 20 years[22](on average, about eight years).[23] While typically there are few or no symptoms at first, near the end of this stage many people experience fever, weight loss, gastrointestinal problems and muscle pains.[16] Between 50 and 70% of people also develop persistent generalized lymphadenopathy, characterized by unexplained, non-painful enlargement of more than one group of lymph nodes (other than in the groin) for over three to six months.[15]
Although most HIV-1 infected individuals have a detectable viral load and in the absence of treatment will eventually progress to AIDS, a small proportion (about 5%) retain high levels of CD4+ T cells (T helper cells) without antiretroviral therapy for more than 5 years.[19][24] These individuals are classified as HIV controllers or long-term nonprogressors(LTNP).[24] Another group consists of those who maintain a low or undetectable viral load without anti-retroviral treatment, known as "elite controllers" or "elite suppressors". They represent approximately 1 in 300 infected persons.[25]
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