SUBSTANCE ABUSE AND AIDS

AIDS stands for acquired immunodeficiency syndrome: AIDS is a life-threatening disease that results from severe damage to part of the body's cellular immune system—the defense system against opportunistic infections and some cancers. The disease is acquired (as opposed to genetic or hereditary) and presents a myriad of clinical manifestations (syndromes) that result from severe damage to the immune system. AIDS was first identified in 1981 among homosexual men in California and New York, and among illicit injected-drug abusers in New York City. After 1981, the numbers and types of AIDS patients increased rapidly; it was diagnosed in millions of persons throughout the world. In the United States alone, the Centers for Disease Control (CDC) estimated in 1996 that 1 million persons were HIV-positive and 223,000 were living with AIDS.

By 1996, injecting drug abusers accounted for 26 percent of cases among men, 70 percent of cases among women, and about 55 percent of pediatric cases—the children of mothers who are either injecting drug abusers or the sexual partners of male injecting drug abusers. As of 1997, it was estimated that 84 percent of HIV-positive women were of childbearing age; 41 percent of them were drug abusers. AIDS is one of the 10 leading causes of death in children between one and four years of age. Women with AIDS do not live as long as men, though the reasons for this finding are still unclear. The finding has been attributed to the hormonal changes of pregnancy, to poverty, and to violence against women. AIDS has been diagnosed among injectors of various illicit substances, including Opiates, Cocaine, Amphetamines, and Anabolic Steroids. AIDS has also been reported among non-injecting drug abusers, such as alcoholics, cocaine "snorters," and crack (cocaine) smokers, who have been infected through sexual contact. An epidemic like AIDS that spans the continents is appropriately called a pandemic.

CAUSE

AIDS is caused by a viral infection. In the United States, the virus is called HIV (for human immunodeficiency virus); it is one of a group of viruses called retroviruses (so-called because they can make DNA copies of their RNA—the reverse of what typically occurs in animal cells). In 1983, French researchers discovered the virus, which they had linked to an outbreak of enlarged lymph nodes (one early sign of HIV infection) that had been reported among French male homosexuals. The French named it the lymphadenopathy-associated virus (LAV). In 1984, U.S. researchers isolated HIV from AIDS patients and named it human T-lymphotropic virus type III (HTLV-III). American investigators found a way to grow HIV in laboratories in large amounts, which led to the development of laboratory tests that detect HIV infection.

HIV gradually destroys certain white blood cells called T-helper lymphocytes or CD4+ cells. The loss of these cells results in the body's inability to control microbial organisms that the normal immune system controls easily. These infections are called opportunistic because they take advantage of damage to part of the immune system. A few select cancers are also frequently diagnosed, such as Kaposi's sarcoma, a cancer of blood vessels, which appears as purplish spots on the skin or mucous membranes.

The sharing of needles contaminated with HIV for injecting drugs of abuse may lead to infection with HIV—but drug abuse may also act as a cofactor with HIV, affecting the development of AIDS. A co-factor in AIDS is a non-HIV-related influence operating in conjunction with HIV to affect the cause of the disease. For example, HIV-infected individuals who continue to inject drugs and/or continue tobacco use may not survive as long as those who do not abuse those substances. The abuse of nitrite Inhalants ("poppers") among HIV-infected homosexual men may promote the development of Kaposi's sarcoma.

SIGNS AND SYMPTOMS

Early HIV Infection.

The natural history of HIV disease and the time intervals between clinical events vary greatly from individual to individual. The general course, however, is one of exposure to HIV, which leads to infection. Within a few weeks or months of infection, laboratory evidence of infection can be detected as the presence of virus in the blood (viremia) or the appearance of the p24 antigen. Antibodies to HIV are found in the blood and indicate that infection has occurred. Some patients develop flulike symptoms resembling mononucleosis or peripheral nerve abnormalities that are self-limited. This first stage of HIV infection is called the acute retroviral syndrome. Most patients have no symptoms during this period.

Latency Period.

Over the ensuing years of a second, or latency, period (1&endash;15 or more years), laboratory evidence of a decreasing number of helper T-lymphocytes can be measured. As the helper T-lymphocyte count decreases, patients are more likely to develop such signs and symptoms as enlarged lymph glands, fatigue, unexplained fever, weight loss, diarrhea, and night sweats. At about the same time or later, patients develop opportunistic infections or cancers. The diagnosis of one of the opportunistic infections or cancers indicates that the patient has developed AIDS. Pneumocystis carinii pneumonia, a fungal infection of the lung, is the most common opportunistic infection among AIDS patients. Other opportunistic infections include candidiasis of the mouth (thrush), cryptococcal meningitis, amebiasis, and cryptosporidiosis. Tuberculosis is another serious infection that has become increasingly common because of the AIDS pandemic.

Late-Stage AIDS.

Late-stage AIDS is usually marked by a sharp decline in the number of lymphocytes, followed by a rise in the number of opportunistic infections and cancers. Kaposi's sarcoma is the most common cancer among AIDS patients. Kaposi's sarcoma usually arises in the skin and looks like a bruise or an area of bruises, but it grows and spreads to the internal organs. Another common type of cancer in late-stage AIDS is a form of lymphoma, or a tumor of the lymphatic system. Patients with late-stage AIDS may also develop inflammations of the muscles, arthritis-like pain in the joints, and AIDS dementia complex. AIDS dementia complex is marked by loss of reasoning ability, apathy and loss of initiative, loss of memory, and unsteadiness or weakness in walking.

DIAGNOSIS AND TREATMENT

Infection with HIV can be diagnosed with a blood test measuring antibodies to the virus. Antibodies are proteins produced by certain white blood cells in response to injection. The HIV antibody test became widely available in 1985. As of the late 1990s patients were usually given an enzyme-linked immunosorbent assay (ELISA) test for the presence of HIV antibody. Positive ELISA results are then tested with a western blot assay for confirmation. The polymerase chain reaction (PCR) test can be used to detect the presence of nucleic acids from HIV in the very small number of patients who have false-negative results on the ELISA and Western blot tests. The use of these tests by blood banks has greatly reduced the chances of contracting infection from transfusions.

Although a cure or vaccine for AIDS had not been discovered as of 2000, three groups of antiviral drugs are used to treat HIV infection.

Nucleoside Analogues.

These drugs work by interfering with the replication process of the HIV virus. They include zidovudine (ZDV, AZT), didanosine (ddI), zalcitabine (ddC), stavudine (d4T), and lamivudine (3TC).

Nonnucleoside Reverse Transcriptase Inhibitors.

These drugs work by blocking the activities of the RNA and DNA in infected cells. They include nevirapine and delavirdine. The drawback of this group of drugs is that the virus quickly develops resistance to them.

Protease Inhibitors.

These are considered the most potent antiviral drugs. They inhibit the viral proteinase enzyme, which results in noninfectious particles of virus. The protease inhibitors include saquinavir, ritonavir, indinavir, and nelfinavir.

As of 1999 through 2000, these drugs were usually given in combinations of at least two and preferably three compounds. Triple combinations including one of the protease inhibitors are considered the most powerful antiviral regimens. All antiviral treatment regimens must be individualized to the patient.

HIV TRANSMISSION

HIV can be transmitted from person to person in three ways: (1) by contact with infected blood or blood components; (2) through intimate sexual contact; and (3) from an infected pregnant mother to her fetus. Drug abusers commonly become infected by sharing needles, syringes, and other injecting paraphernalia; injecting substances—such as heroin, cocaine, and amphetamines—after an HIV-infected person uses the needle and syringe causes direct inoculation of HIV. Using any paraphernalia contaminated with blood (even in quantities too small to see) can result in HIV or hepatitis B virus transmission. Sexual contact is a common route of transmission from drug abusers to their sex partners (who can transmit the virus to other sex partners, other drug abusers, or to unborn children). Health-care workers have also been exposed to HIV through unprotected or accidental direct contact with blood of infected patients in health-care settings.

We do not know how many individuals are HIV infected worldwide. The World Health Organization (WHO) estimated in 1995 that 18 million adults and 1.5 million children had been infected worldwide, producing about 4.5 million cases of AIDS. Most of these cases are in the developing countries of Asia and Africa. Numerous HIV surveys have been conducted among injecting drug abusers in several parts of the world. As those currently HIV infected progress to AIDS, the health-care systems and social fabric of many nations will be severely challenged.

HIV does not appear to be contagious in other settings. No known cases of AIDS have been linked to transmission in nonsexual social or household situations, through air, food, or water, or by mosquito bites.

PREVENTION AMONG DRUG ABUSERS

Methadone Maintenance Treatment (MMT).

Because no reliable cure or vaccine for HIV infection exists now (nor is one expected to exist in the near future), the hope for slowing the spread of HIV infection is through education and behavior-changing strategies. Among injecting drug abusers, the most effective way to avoid HIV infection is to stop sharing infected needles, or, better yet, stop injecting drugs, and to avoid sexual contact with individuals who may be HIV-infected. Former drug abusers in drug-abuse treatment have been consistently found to have lower HIV infection rates than those on the streets. Methadone maintenance therapy has been shown to be an effective therapy for opiate addicts and has decreased HIV transmission among compliant patients. As of 2000, the rates of patient compliance among patients in maintenance methadone treatment were higher among women than men; higher among Caucasians than among minorities; and higher among older than younger patients. The National Institute on Drug Abuse (NIDA) continues to conduct research on innovative treatment for drug abuse.

HIV Counseling.

The use of HIV antibody tests, counseling about HIV infection, and partner notification projects in drug-abuse treatment programs have thus far met with limited success. A Morbidity and Mortality Weekly Report issued in June 2000 noted that men who have sex with men and also abuse drugs (MSM/IDU) still pose unique challenges to slowing the AIDS epidemic because they have multiple risks for HIV infection and transmission. The findings for the period 1985 to 1998 show that over half of MSM/IDU with AIDS were non-Hispanic blacks and Hispanics; that most came from large metropolitan areas; and that the incidence of AIDS has slowly declined since 1996.

Needle Exchange Programs.

Some investigators recommend that injecting drug abusers employ "safer" needles and syringes. One approach to reduce HIV transmission among injecting drug abusers is to educate addicts about cleaning needles and syringes between each use. Mechanical cleansing to remove any visible evidence of blood or other debris in the paraphernalia is followed by rinsing with a disinfectant. Of the various disinfectants tested, household bleach appears to be the most effective against HIV. Another approach has been the establishment of needle/syringe exchange programs. Rigorous studies of the effects of such programs on (1) HIV transmission and (2) the recruitment of "new" injectors of drugs will help to show how useful this strategy is.

Newer Strategies.

A more recent proposal concerns evaluation of injecting drug abusers for concurrent psychiatric disorders, particularly major depression and antisocial personality disorder, as drug abusers with these disorders are at higher risk of HIV infection. Another strategy is the extension of HIV prevention efforts to abusers of other drugs, most notably cocaine and amphetamines. Lastly, the high rates of HIV infection among Native Americans and Spanish-speaking drug injectors born outside the United States, respectively, have led to concerted efforts to develop group-specific interventions and to recruit outreach workers from these affected groups.

(See also: Alcohol and AIDS ; Complications: Route of Administration ; Injecting Drug Users and HIV ; Needle and Syringe Exchanges and HIV/AIDS ; Sweden, Drug Use in )

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Harry W. Haverkos

D. Peter Drotman

Revised by Rebecca J. Frey