AIDS

ebn benghazi
25 Dec, 2010
Acquired Immune Deficiency Syndrome or HIV infection
  • AIDS is caused by infection with the human immunodeficiency virus HIV-1.  The HIV virus infects cells in the body that fight infection. The primary cell infected is the CD4 lymphocyte, but it infects other infection-fighting cells as well.  This causes immune system impairment and difficulty fighting infection. Because the immune system has a role in cancer prevention, there is also an increase in certain cancers.  To be HIV positive means that one is infected with the HIV virus.  To be given the diagnosis of AIDS, one must be infected with HIV, which means that the HIV infection has compromised the immune system to the extent that an AIDS-defining illness (one of multiple illnesses) has occurred.  Before current "triple therapy" was developed, nearly all those who were HIV positive went on to develop AIDS.  Now it is not the case.  But, not all persons respond to "triple therapy" and a proportion still goes on to develop AIDS.

  • HIV syndrome occurs 3 to 6 weeks after infection and includes :
    1. Fever
    2. Sweats
    3. Sore throat
    4. Enlarged lymph glands
    5. Headaches
    6. Weight loss
    7. Joint aches
    8. Muscle aches
    9. Diarrhea
    10. Rash
    11. Oral ulcers
  • Symptoms of any opportunistic illness (i.e., bacteria, fungi, protozoa, and viruses)
  • Some may not develop any symptoms for years after exposure.
  • Candidiasis (white patches in mouth)
  • Pneumocystis carinii (lung infection characterized by dry cough and shortness of breath)
  • Atypical mycobacterium
  • Toxoplasmosis (infection in brain with confusion)
    Progressive multifocal leukoencephalopathy (causes dementia)
  • Herpes simplex (causes ulcers that persist over 1 month)
  • Lymphoma (enlarged glands)
  • Kaposi's sarcoma (purple skin lesions)
  • Diarrheas -- cryptosporidosis and isoporiasis
  • Recurrent pneumonias
  • Tuberculosis (cough)
  • HIV encephalopathy (dementia)
  • HIV wasting syndrome
  • Cytomegalovirus infection /blindness
  • Cryptococcosis (especially meningitis)
  • Disseminated coccidiomycosis (fungal infection found in Southwest United States, typically affects lungs, but in HIV may go into spinal fluid and cause meningitis)
  • AIDS wasting (weight loss) syndrome
  • Depression and social/family isolation
  • Neuropathies
  • Pain

  • HIV can be found in many types of bodily secretions (i.e., semen, urine, tears, saliva, blood, breast milk, spinal fluid, vaginal secretions).  However, the risk of transmission is highest through semen and sexual activities.
  • Anal sex -- highest transmission rate
  • Heterosexual sex, homosexuals, bisexual males who engage in unprotected sex
  • Intravenous drug abusers who share needles
  • Oral Sex -- lower, but risk still present
  • Blood and blood product transfusions between 1977-1985 (now rare, because blood products are carefully screened)
  • Contaminated needle stick as in healthcare professionals (1:300 risk)
  • Children born to mothers with HIV infection
  • Not spread through casual contact such as touching, hugging, or sharing toilet seats
  • Not transmitted by insect bites such as mosquitoes
  • No documented cases of HIV infection from saliva or tears; however, if there is an open sore on the skin or mouth, the risk increases.

  • Examination:
  • May be normal
  • Signs & symptoms of AIDS-defining illnesses (see below)
  • Laboratory Findings:
    1. HIV antibody test -- the HIV virus multiplies in the body for weeks or months before the body responds by making antibodies to it, at which time the HIV test is considered positive.  Decreased CD4 lymphocyte (also known as T-helper cells) count (the lower the count the more likely to develop infections and illness)
    2. Symptoms begin to occur with CD4 count falling below 350/ml
    3. Anemia
    4. Polyclonal hypergammaglobulenimia
    5. High cholesterol
    6. Skin antigen testing fails to react to typical antigens

  • The goal of treatment is to keep CD4 count above 200/ml, prevent/control opportunistic infections, and improve the quality of life.
  • Anti-retroviral drugs (Highly Active Anti Retroviral Therapy or HAART) -- these interfere with the HIV virus' ability to replicate.  Some common ones are listed below:
  • Nucleoside analogs
    1. Zidovudine (AZT)
    2. Zalcitabine (ddC)
    3. Lamivudine
    4. Stavudine
  • Protease inhibitors
    1. Indinavir
    2. Ritonavir
    3. Nelfinavir
    4. Saquinavir
  • Triple therapy -- it has been found that combining two nucleoside analogue drugs with one protease inhibitor can substantially reduce the viral burden, infection rate, and death rate in HIV infection.
  • Post-exposure prophylaxis (e.g., after a needle stick)
    1. AZT probably beneficial
    2. AZT plus other antiretroviral drugs probably will be shown to be more effective.

  • Before the more effective "triple therapy" was developed, various regimens were recommended to prevent specific infections.  For example, Trimethoprim-Sulfamethoxazole for Pneumocystitis carinii included various regimens that are now reserved for those who fail to respond or are intolerant of "triple therapy."
    1. Abstinence
    2. Safe sex (use of condoms and oral barriers)
    3. HIV testing prior to a relationship
    4. Stop intravenous drug abuse, sharing of dirty needles, and other high-risk behaviors.
    5. Healthy lifestyle and join support groups if at risk
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