What You Should Know About
Tuberculosis
Tuberculosis (TB) is an infection caused by a bacterium known as Mycobacterium tuberculosis. TB affects mainly the lungs, although other parts of the body may be affected as well. The infection is contagious, and bacteria can spread from person to person in the air. Usually, someone with the active disease coughs the bacteria into the air, where someone else inhales it.
Most people who inhale the TB bacteria don't develop active TB, nor can they transmit the infection to other people. Their immune system inactivates, or walls off the Tbc bacillus. Of the 10% or so who do develop active disease, most have low resistance or a large exposure that overcomes the body's normal defenses.
Diagnosing TB
To diagnose TB, a doctor will consider the symptoms, the proximity of possible exposure to the start of the symptoms, and the results of a tuberculin skin test, a chest X-ray, and a sputum test.
Symptoms
Although active TB may be present without any specific symptoms, it usually
causes a number of symptoms, including coughing, blood in the sputum, night sweats, unexplained weight loss, loss of appetite, fever, chills, and malaise.
Tb skin test
In a TB test, a small drop of liquid is injected into the skin of your forearm. The liquid contains killed TB bacteria. If you have TB, or have been exposed to the TB bacillus in the past your body will react to the liquid and form a red welt at the site of the test. A trained health care provider, usually a doctor or nurse, will look at the test site after 48 to 72 and determine whether the reaction indicates a positive test result. If the test is positive it means that there has been prior exposure to the TB bacteria, but does not mean that there is an active TB infection. Further testing is necessary to make that decision.
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