Tuberculosis (TB)
Tuberculosis (TB) is an infection, primarily in the lungs (a pneumonia), caused by bacteria called Mycobacterium tuberculosis. It is spread usually from person to person by breathing infected air during close contact. TB can remain in an inactive (dormant) state for years without causing symptoms or spreading to other people. When the immune system of a patient with dormant TB is weakened, the TB can become active (reactivate) and cause infection in the lungs or other parts of the body.
The risk factors for acquiring TB include close-contact situations, alcohol and IV drug abuse, and certain diseases (e.g., diabetes, cancer, and HIV) and occupations (e.g., health care workers).
The most common symptoms of TB are fatigue, fever, weight loss, coughing, and night sweats. The diagnosis of TB involves skin tests, chest x-rays, sputum analysis (smear and culture), and PCR tests to detect the genetic material of the causative bacteria. Inactive tuberculosis may be treated with an antibiotic, isoniazid (INH), to prevent the TB infection from becoming active. Active TB is treated, usually successfully, with INH in combination with one or more of several drugs, including rifampin, ethambutol, pyrazinamide, and streptomycin.
Drug-resistant TB is a serious, as yet unsolved, public health problem, especially in Southeast Asia and in prison populations. The occurrence of HIV has been responsible for an increased frequency of tuberculosis. Control of HIV in the future, however, should substantially decrease the frequency of TB.
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