Tuberculosis (TB) is an infectious disease that is caused by a bacterium called
Mycobacterium tuberculosis. TB primarily affects the lungs, but it can also affect organs in the central nervous system, lymphatic system, and circulatory system.
The disease was called “consumption” in the past because of the way it would consume infected people from within. When someone becomes infected with TB, the bacteria in the lungs multiply causing pneumonia; the patient experiences chest pain and has a persistent cough which often brings up blood.
In addition however, lymph nodes near the heart and lungs become enlarged. As the bacteria spread to other parts of the body they are interrupted by the body’s immune system.
The immune system forms scar tissue or fibrosis around the bacterium, which helps fight the infection and prevents it from spreading within the body and to other people.
If the bacteria manage to break through the scar tissue the disease returns to an active state; pneumonia develops and there is damage to kidneys, bones, and the meninges that line the spinal cord and brain.