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    Tuberculosis often curable with six-month treatment, observation

    Age-old 'white plague' still a concern for public health because of increased multiple drug resistance

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    TUBERCULOSIS (TB), a chronic bacterial infection, is one of the world's oldest infectious diseases. It spreads through the air and usually infects the lungs, although other organs may also be involved.


    First-Line Drugs for Tuberculosis
    Most people infected with tuberculosis don't have any symptoms; they have what is called "latent TB." Some of them go on to develop "active TB," with symptoms such as weight loss, fever, night sweats, cough, chest pain, and bloody sputum. People who are malnourished or have impaired immune systems are particularly vulnerable to TB. In the United States, approximately 16,000 people have active TB, while an estimated 10 million to 15 million people are infected with tuberculosis without having any symptoms. About one in 10 of these people will develop active TB at some time in their lives.

    While the incidence of TB in the United States continues to decline, "there's a persistent problem in certain homeless populations as well as among immigrants from high-incidence countries," says Paul R. Cieslak, MD, manager of the communicable disease program for the Oregon Department of Human Services. "In Oregon, for example, more than half the cases now are in people who were born outside the country, mostly from Southeast Asia or from Latin America. They may come here with latent tuberculosis, showing no symptoms, and then five or 10 years later develop an active case."

    One of the greatest problems in TB treatment is the emergence of multi-drug-resistant strains of the bacteria. To ensure that patients take antibiotics for the full course of treatment, they should be monitored with "directly observed therapy." That means a healthcare worker meets the patient at a convenient place (home, or work, or the TB clinic.) The patient takes the medication while the healthcare worker watches. "Every form of tuberculosis should ideally receive directly observed therapy, but it's most important for those who have multi-drug-resistant TB," says Mark Abramowicz, MD, editor of The Medical Letter on Drugs and Therapeutics, a non-profit newsletter that critically appraises drugs.

    All cases of TB should be tested for antimicrobial susceptibility, but the results generally do not become available for at least two weeks, and sometimes much longer. This means patients are usually started on a four-drug regimen, which includes isoniazid, rifampin, pyrazinamide and ethambutol. "If the patient does not have drug-resistant TB, and if things are going well after two months of the four-drug regimen, then they can be shifted to a two-drug regimen," Dr. Abramowicz says.

    Treatment of multi-drug-resistant TB is based on limited data, Dr. Abramowicz says. "Confirmed cases of multi-drug-resistant TB should be treated with directly observed therapy, including at least four drugs, with treatment usually lasting 18 to 24 months. If possible these patients should be referred to clinicians who have experience in treating these cases."

    TUBERCULOSIS AND MANAGED CARE Once someone has been diagnosed with tuberculosis, the public health system is set up to handle follow-up care. "Managed care organizations have the responsibility, while they're making the diagnosis, to ensure that the patient doesn't expose other people to the disease," Dr. Cieslak says. "That means the patient should be kept in isolation, healthcare workers should be protected, and specimens should be taken for diagnosis. But once initial therapy has been started, and the disease has been reported to the health department, public health may take over a lot of the responsibility for treatment."

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