Human immunodeficiency virus (HIV) is caused by a retrovirus, HIV 1 or HIV 2. Both retroviruses cause the infection, but HIV 1 has been found in the Western Hemisphere, and HIV 2 is principally from West Africa. Infection occurs when a glycoprotein on the surface of the virus combines with the CD4 receptors found on various critical sites, e.g., lymphocytes, nerve cells and lymph nodes causing them to break down and progressively lose their immunological functions.

The retrovirus HIV uses the reverse transcriptase enzyme to convert its viral ribonucleic acid (RNA) to viral deoxyribonucleic acid (DNA). The viral DNA then becomes a part of the host DNA. This change in the DNA causes malfunction of the cell causing it to create more viruses.

Finally, the cell ruptures and releases more HIV into the bloodstream. This weakening of cell immunity increases a patient's susceptibility to a wide spectrum of disorders. Acquired immunodeficiency syndrome (AIDS) is a secondary infection, and results from HIV infection. The Centers for Disease Control (CDC) defines three related disease categories. These are noted in the chart below.

1993 Revised Classification System for HIV Infection and AIDS

In 1984, HIV 1 was identified as the cause of AIDS. HIV transmission requires contact with body fluids containing the retrovirus. HIV may be present in a variety of tissues, exudate, or any fluid that contains plasma, lymphocytes, blood, semen, vaginal secretions, cerebrospinal fluid, and breast milk. Though possible, transmission by saliva is rare, and tears and sweat may not contain enough virus to be infectious. The most common means of transmission are the direct transfer of bodily fluids either in sexual practices, the sharing of contaminated needles, or the transmission of the virus from mother to infant in utero, during labor and delivery, or in breast milk.

A wide variety of disease manifestations take place during the early infection. One to three weeks after the initial infection, people experience acute flu-like symptoms ranging from fever, rash, fatigue, sore throat, swollen lymph nodes, sore muscles, gastrointestinal complaints, and diarrhea. During this time, the virus reproduces rapidly. The acute symptoms may disappear, but complications of AIDS, such as persistent generalized lymphadenopathy (PGL) remain.

The time line for the disease is as follows: acute retroviral symptoms become apparent in one to three weeks, HIV antibody tests become positive in 2 to 6 months, and the median time between HIV and AIDS could be as long as ten years.

A diagnosis of AIDS cannot be made until the patient meets the criteria established by the Centers for Disease Control (CDC).

Diagnostic Criteria for AIDS from CDC: AIDS is diagnosed when an individual with HIV infection develops at least one of these additional conditions:

• The CD4+ lymphocyte count drops below 200/ml.

• The development of one of the following opportunistic infections (OI):

  1. Fungal: candidiasis of bronchi, trachea, lungs, or esophagus; disseminated or extrapulmonary histoplasmosis.

  2. Viral: cytomegalovirus (CMV) disease other than liver, spleen, or nodes; CMV retinitis (with loss of vision); herpes simplex with chronic ulcer(s) or bronchitis, pneumonitis, or esophagitis; progressive multifocal leukoencephalopathy (PML); extrapulmonary cryptococcosis.

  3. Protozoal: disseminated or extrapulmonary coccidioidomycosis, toxoplasmosis of the brain.

  4. Pneumocystis carinii: Pneumocystis carinii pneumonia (PCP), chronic intestinal isosporiasis; chronic intestinal cryptosporidiosis.

  5. Bacterial: Mycobacterium tuberculosis (any site); any disseminated or extrapulmonary Mycobacterium.

  6. Mycobacterium kansasii: recurrent pneumonia, recurrent Salmonella septicemia.

• The development of one of the following opportunistic cancers: invasive cervical cancer, Kaposi's sarcoma (KS), Burkitt's lymphoma, immunoblastic lymphoma, or primary lymphoma of the brain.

• Wasting syndrome defined as loss of 10% or more of ideal body mass.

• The development of dementia.

There is a rapid serum test for HIV antibody. However, finding HIV RNA in the blood is the best diagnostic test in the early stages before antibodies can be detected. A blood test which detects antibodies to HIV is the ELISA (enzyme-linked immunosorbent assay). If this test is positive it should be repeated on the same sample. If it is positive a second time, then a Western blot is used.

The progression of HIV infection is monitored with cultures, CD4 lymphocyte counts, white blood count, red blood count, erythrocyte sedimentation rate (ESR), and liver function tests. In addition, laboratory tests are performed to check for reactivation of previous diseases such as tuberculosis, syphilis, toxoplasmosis, or histoplasmosis.

A number of new treatments have emerged in the 1990s. The approach to treatment has changed due to a better understanding of the progression of HIV and the new methods that quickly measure the effects of drugs on HIV in the blood.

Drug combinations that target two enzymes (HIV reverse transcriptase and protease) have become standard practice. Use of single drugs is not recommended.

A regimen that includes two to four drugs can minimize viral reproduction, maintain immune function, and lessen the possibility of drug-resistant viral mutation. The success of treatment and longevity of response to various combinations of drugs will vary in the suppression of viral replication, and requires constant compliance with a combination of drugs.

Antiretroviral drugs may cause various adverse effects depending on the drug and dosage. Some side effects include headache from ZDV (Zidovudine) that eventually becomes less severe; and stomach discomfort from didanosine that may be indicative of pancreatitis.

Conditions that can be recognized from blood tests before they become symptomatic, e.g., anemia, pancreatitis, hepatitis, and glucose intolerance require regular monitoring of hematology and blood chemistries. The length of time therapy should continue has not been determined. Medications are taken for as long as antiretroviral results outweigh negative side effects and costs. Some of the serious adverse effects of antiretroviral drugs are: anemia, leukopenia, peripheral neuropathy (muscle weakness and numbness), kidney stones which result in backpain, hematuria and kidney failure from urine obstruction.

Even with the increases made in the understanding of how HIV affects the immune system, there is no cure or vaccine for those with AIDS.

1. "The term "approved medication(s)" includes medications prescribed as part of a research protocol at an accredited medical institution." (38 CFR §4.88b [Schedule of ratings-systemic diseases])

2. "Psychiatric or central nervous manifestations, opportunistic infections, and neoplasms may be rated separately under appropriate codes if higher overall evaluation results, but not in combination with percentages otherwise assignable above." (38 CFR §4.88b [Schedule of ratings-systemic diseases])

3. May be entitled to special monthly compensation where the veteran has a single service-connected disability rated as 100% and/or other requirements/qualifications under 38 CFR §3.350 [Special monthly compensation ratings]. Also reference M21-1MR, Part III, Subpart iv, Chapter 6, Section B, Topic 3 [Inferred Issues & Ancillary Benefits].

4. If service connection is at issue and it is indicated in the evidence that the HIV-related illness was the result of intravenous drug abuse, Authorization must conduct a Line of Duty/Willful Misconduct determination.