"In a normal infection, your immune system attacks the invading bacteria and kills them. Then it removes the damaged tissue and the dead bacteria. In a skin infection we see the aftermath of this as pus. Tuberculosis affects a body differently. When a person has untreated tuberculosis in their lungs, the greatest danger is not from the bacteria itself, but from the person's own body. The immune system attempts to wall off the area around the bacteria, which results in a pocket of dead lung tissue inside the living lung. If left untreated these walled off areas increase and in about 50% of cases, cause the death of the infected person. Notice that it is not the bacteria that kills people, but the response of the body to the bacteria."

The residue of the response is as bad as or worse than the disease. The linked article is VERY good association between TB and emotional bruising.