General, HIV/AIDS | June 13, 2014 | Author: The Super Pharmacist
The difference between HIV and AIDS. While the two terms are sometimes used interchangeably, there is a difference between HIV infection and AIDS. HIV infection simply means that someone has the Human Immunodeficiency Virus (HIV) in their body. Likewise, someone who is HIV-positive means that they have been tested for the presence of HIV and diagnosed as infected. Once acquired, the infection is permanent (except in some rare cases; see below). Someone with AIDS is also infected with HIV, but the infection has progressed to a point that the person is said to have AIDS or Acquired ImmunoDeficiency Syndrome.
Someone has AIDS if one or both of the following conditions has occurred:
With successful treatment, a person with HIV infection may have a T-cell count that returns to a level above 200/mm. Likewise, someone may have an AIDS defining illness that is successfully treated with for example antibiotics. Nevertheless, once a diagnosis of AIDS has been made, the patient is always considered to have AIDS. This is true even if the person no longer qualifies for the diagnosis based on CD4+ T-cell count or the presence of an AIDS-defining illness.
The number and types of illnesses that define AIDS in an HIV-positive patient has changed slightly since the disease was first characterised in the 1980s. Currently, people use the 1993 definition of AIDS which includes the AIDS defining illnesses.
There are two groups of individuals that are relatively protected from the effects of HIV: long-term non-progressors and elite controllers.
Long-term non-progressors are individuals who do not display symptoms of HIV or AIDS even without HIV therapy. 4% to 7% of HIV-infected patients will maintain CD4+ T-cell counts above 500/mm3 without treatment or symptoms of HIV. Long-term non-progressors likely have a low viral count and a robust immunologic response early in the infection that leads to this extended period without disease.
Elite controllers are positive for HIV but do not have any detectable copies of the virus and have relatively high CD4+ T-cell counts. Elite controllers are fairly rare, occurring in about one out of every 300 HIV-infected patients. It is not clear why elite controllers can exhibit viral loads roughly equivalent to those who are on highly active anti-retroviral therapy; however, it is possible that CD8+ T-cells participate in a robust immunological response against the virus.
The emergence of highly active anti-retroviral therapy (HAART) has radically improved the treatment of HIV and AIDS. It has changed HIV infection from a universally fatal disease to a chronic illness that can be managed and controlled.
HAART is the use of three or more anti-retroviral drugs, of different drug classes, to target various parts of the virus simultaneously.
HAART should be started in the following individuals:
Antiretroviral therapy should strongly be considered for:
One might wonder why not all HIV-positive patients are immediately started on HAART therapy after diagnosis. Starting treatment with HAART commits the patient to a lifelong, daily regimen with multiple drugs that can cause some rather challenging adverse effects. These side effects can create short- and long-term problems for the patient. In addition, HAART therapy is expensive.
Patients who do not take the prescribed regimens faithfully are at very high risk of creating a drug-resistant strain of HIV (since the virus mutates so readily and so quickly). This poses a risk to the patient, but is also a serious public health concern. In fact, there is a risk of developing resistance even when patients take the prescribed drug regimen faithfully.
The decision to start HAART is an important one. The decision-making process should start with a detailed and thorough discussion between the patient and a physician who has experience in treating HIV and AIDS.
Opportunistic infections Once CD4+ T-cell counts drop below certain levels, bacterial and fungal infections are more likely to occur because a sufficient immune response is not possible. In these cases, the patient is started on one or more antibiotics to prevent an opportunistic infection. These prophylactic antibiotics are taken until CD4+ T-cell counts rise due to HAART therapy.
From the Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. JAMA. Feb 10 1993;269(6):729-730.
1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. MMWR Recomm Rep. Dec 18 1992;41(RR-17):1-19.
Pantaleo G, Menzo S, Vaccarezza M, et al. Studies in subjects with long-term nonprogressive human immunodeficiency virus infection. N Engl J Med. Jan 26 1995;332(4):209-216. doi:10.1056/nejm199501263320402
Dinoso JB, Kim SY, Siliciano RF, Blankson JN. A comparison of viral loads between HIV-1-infected elite suppressors and individuals who receive suppressive highly active antiretroviral therapy. Clin Infect Dis. Jul 1 2008;47(1):102-104. doi:10.1086/588791
Consolidated Guidelines on the Use of Antiretroviral Drugs for Treating and Preventing HIV Infection: Recommendations for a Public Health Approach. Geneva: World Health Organization 2013.; 2013.
Phillips AN, Leen C, Wilson A, et al. Risk of extensive virological failure to the three original antiretroviral drug classes over long-term follow-up from the start of therapy in patients with HIV infection: an observational cohort study. Lancet. Dec 8 2007;370(9603):1923-1928. doi:10.1016/s0140-6736(07)61815-7