General Information on Tuberculosis

Tuberculosis, commonly known as TB, is a bacterial infection caused by the bacteria Mycobacterium tuberculosis. Tuberculosis can affect any organ of the body, but typically infects the lungs. Tuberculosis treatment is available, but it is a lengthy process taking many months. An estimated 22,000 new cases of tuberculosis are diagnosed in the United States each year, with a total of 8 million new cases identified worldwide. Untreated active tuberculosis can be fatal.

How Tuberculosis Spreads

• The main way that tuberculosis is spread to other people is through the air. A person with an active tuberculosis infection in their lungs (pulmonary tuberculosis) will release the bacteria into the air when he exhales, coughs or sneezes. Others who inhale the released bacteria will then become infected. Extrapulmonary tuberculosis (infection in areas of the body outside the lungs) is rarely contagious, except for rare cases transmitted during an autopsy or medical procedures involving the affected organ.

Risk Factors

• Anyone can contract tuberculosis, but it is more likely to develop if you have certain risk factors. Risk factors include people who have an illness that suppresses the immune system, like HIV or AIDS; are health care workers; spend time in crowded areas like nursing homes, prisons or homeless shelters; live with someone who has an active case; are homeless; are alcoholics or drug abusers; or travel to areas where the disease is prevalent. Individuals in these high-risk groups should get tested twice a year for TB.

Symptoms

• The initial TB infection is so mild that it is usually mistaken for influenza or the common cold. Symptoms of initial TB infection include fatigue, coughing and a low-grade fever. Around 90 percent of those infected with the tuberculosis bacteria never develop an active case of TB. This is called a latent infection. The remaining 10 percent go on to develop an active case of TB.
  Symptoms of an active pulmonary infection include sharp pain when breathing or coughing, coughing up thick mucus that may contain blood, fever, night sweats, lack of appetite and accompanying weight loss, fatigue and increased heart rate. Infections that spread to other areas of the body will cause other symptoms that will vary depending on the area involved.

Diagnosis

• A simple tuberculin skin test can be performed to screen for tuberculosis. TB antigens are injected under the skin of the patient by a healthcare provider. The injection site is examined 2 days later to see if a red bump has appeared, indicating exposure to TB. Further tests may be performed if the skin test is positive, to confirm the diagnosis. Mucus samples or a chest x-ray can reveal pulmonary tuberculosis, as can a biopsy of suspected organs infected with the tuberculosis bacteria.

Treatment

• Treatment for latent TB consists of an antibiotic that is taken for a 9-month period. Successful treatment will greatly reduce the chance of developing an active case of TB. Treatment for active TB usually involves taking four antibiotics for a period of 2 months, after which time the number is reduced to two antibiotics. Treatment will continue for a number of months, and in some cases treatment may go on for years.
  It is crucial that all medications be taken exactly as prescribed during treatment. Many patients are required to undergo direct observational treatment, which requires all TB medication be taken under the observation of a healthcare professional. Failure to take the medication as prescribed can result in longer treatment times or bacteria that are resistant to the prescribed antibiotics.