Tuberculosis (TB) is a disease caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain. Tuberculous arthritis caused by Mycobacterium tuberculosis also has been described. The joints most frequently involved are the spine, hips, knees, wrists, and ankles. Valvular endocarditis due to Mycobacterium tuberculosis also has been reported. If not treated properly, TB disease can be fatal.