AIDS

AIDS

Definition

is a final stage of HIV infection in which certain white blood cells are destroyed, resulting in loss of the body’s ability to protect itself against infectious diseases.

Etiology

Virus HIV which has 2 main strains HIV-1 and HIV-2.

HIV is a lentivirus (a subgroup of retrovirus) that causes the acquired immunodeficiency syndrome (AIDS)

Pathogenesis

The HIV itself doesn’t kill the patient. It destroys the immune system, leaving the patient susceptible to other diseases.

HIV infects a specific type of white blood cells (T-cells). The virus attacks T-cells that have a protein known as CD4 on the outer membrane. This kind of cell is essential in triggering the immune response to infection or other foreign materials. The HIV invades CD4 cells and inserts its own genetic material into them. Thus, it uses the cell’s resources to create more copies of the virus and eventually kills the CD4 cell. After CD4 cells are destroyed, the body is no longer able to fight off infections or kill cancer cells.

Ways of transmission

The AIDS is transmitted through body fluids such as blood, breast milk, semen, vaginal fluids, sharing needles for IV drugs. The virus can be transmitted through organ or tissue transplants. An infected mother may pass the virus on to her unborn child through placenta. Susceptibility to HIV infection increases if there is a damage in or mucous membranes, which allows the virus enter the bloodstream.

HIV can’t be transmitted through simple physical contact.

Methods of diagnostics

Taking anamnesis and 2 types of tests: Screening and confirmatory blood tests.

The first test is very sensitive: it finds something that looks like HIV antibodies. This test is used to screen blood and blood products. The second test is specific it separates the false positives from the true positives of the first test.

Clinical picture

A person, who is infected, may not experience any symptoms.

The earliest symptoms of HIV infection are a low-grade intermittent fever, a rash, swollen lymph nodes, weight loss, and fatigue.

The HIV infection includes 3 stages:

acute infection lasts for several weeks and may include symptoms such as fever, lymphadenopathy (swollen lymph nodes), pharyngitis, rash, myalgia (muscle pain), malaise, and mouth and oesophageal sores; latency stage involves few or more symptoms which can last from 2 weeks to 20 years or more; AIDS, the final stage is defined by low CD4 T cell counts, various opportunistic infections, cancers and other conditions.

Treatment

Various drugs have been developed to fight the AIDS virus. They are AZT (zidovudine), DDI (didanosine). These drugs try to disrupt key chemical reactions in HIV’s metabolic cycle, including those controlling its reproduction. But the virus mutates rapidly, and the drugs lose their effectiveness.

However, there are new antiviral drugs that are used to treat AIDS. They are protease inhibitor, entry inhibitor, reverse transcriptase, inhibitor, and integrase inhibitors. These classes of drugs prevent creation, assembly, and spread of new viruses. A doctor may prescribe a combination of these drug classes known as highly active antiretroviral therapy (HAART).

Treatment for opportunistic infections of AIDS are medications specific for each type of infection.

Complications

Different opportunistic diseases:

Kaposi’s sarcoma, thrush or pseudomembranous candidiasis, pneumocyst carinii pneumonia, tuberculosis, cryptosporidium, gastrointestinal infection, multifocal leukoencephalopathy, cytomegalovirus; cervical cancer in women.

Prevention

Avoiding unprotected sex, sharing needles.

Blood and blood products should be thoroughly tested before being transfused to somebody.

It has been found that taking the drug AZT during pregnancy reduces the chances of passing HIV to the foetus to just 25 percent.