Prepared by: Office of Communications National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda, MD 20892 Public Health Service U.S. Department of Health and Human Services November 1994

Symptoms and Diagnosis

Disseminated MAC can affect almost any organ of the body. It can cause symptoms of fever, weight loss, night sweats, fatigue, loss of appetite, loose stools or diarrhea, abdominal pain, anemia (low numbers of red blood cells) and enlargement of the liver or spleen.

The symptoms of MAC resemble those of many other conditions in people with AIDS. The diagnosis of MAC is made by identifying the organism in blood samples or tissue from affected organs such as bone marrow or liver tissue.

Treatment

Acute Therapy. Doctors use a number of different drug combinations to treat MAC. A special task force of the U.S. Public Health Service recommended that at least two drugs be used, one of which should be either azithromycin or clarithromycin. Doctors frequently add one or more of the following as second, third or fourth agents: ethambutol, clofazimine, rifabutin, rifampin, ciprofloxacin and in some situations amikacin. Treatment should continue for life to prevent recurrence of the disease.

Preventive Therapy. The USPHS task force also recommended that people with HIV and CD4+ T-cell counts of less than 100 should receive treatment to prevent an initial episode of MAC. (CD4+ T cells are the crucial immune cells targeted by HIV.) Before beginning preventive therapy, people with HIV should be tested to be sure that they do not have active MAC or tuberculosis (TB). Multiple drugs are required to treat these infections because the organisms may become resistant to just one drug.

Tests for TB may include an x-ray, tuberculin skin tests and a blood test.

Rifabutin is the drug approved for preventive therapy. It is usually well tolerated, but side effects can include low numbers of white blood cells, low platelet count, an eye infection called uveitis, rash and diarrhea. Rifabutin also may alter the metabolism of certain drugs.

Research

The National Institute of Allergy and Infectious Diseases (NIAID) funds research aimed at finding therapies for treating and preventing MAC disease. Researchers are studying two-drug combinations such as clarithromycin and rifabutin for prevention of MAC.

For information about clinical studies, call the AIDS Clinical Trials Information Service: 1-800-TRIALS-A 1-800-243-7012 (TDD/Deaf Access)

For federally approved treatment guidelines on HIV/AIDS, call the HIV/AIDS Treatment Information Service: 1-800-HIV-0440 1-800-243-7012 (TDD/Deaf Access)

NIAID, a component of the National Institutes of Health, supports research on AIDS, tuberculosis and other infectious diseases as well as allergies and immunology.

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