Tuberculosis (TB) is a life-threatening infection that primarily affects your lungs. Every year, tuberculosis kills nearly 2 million people worldwide. The infection is common — about one-third of the human population is infected with TB, with one new infection occurring every second.
Tuberculosis has plagued human beings for millennia. Signs of tubercular damage have been found in Egyptian mummies and in bones dating back at least 5,000 years. Today, despite advances in treatment, TB is a global pandemic, fueled by the spread of HIV/AIDS, poverty, a lack of health services and the emergence of drug-resistant strains of the bacterium that causes the disease.
Tuberculosis spreads through airborne droplets when a person with the infection coughs, talks or sneezes. In general, you need prolonged exposure to an infected person before becoming infected yourself. Even then, you may not develop symptoms of the disease. Or, symptoms may not show up until many years later.
Left untreated, tuberculosis can be fatal. With proper care, however, most cases of tuberculosis can be treated, even those resistant to the drugs commonly used against the disease.
Symptoms
Although your body may harbor the TB bacteria, your immune system often can prevent you from becoming sick. For that reason, doctors make a distinction between:
- TB infection. This condition, sometimes called latent TB, causes no symptoms and isn't contagious.
- Active TB. This condition makes you sick and can spread to others. However, the infection may be asymptomatic for years, even though it's active and causing damage.
Your immune system begins to attack TB bacteria two to eight weeks after you're infected. Sometimes the bacteria die, and the infection clears completely. In other cases, the bacteria remain in your body in an inactive state and cause no tuberculosis symptoms. In still other cases, you may develop active TB.
TB mainly affects your lungs (pulmonary tuberculosis), and coughing is often the only indication of infection initially. Signs and symptoms of active pulmonary TB include:
- A cough lasting three or more weeks that may produce discolored or bloody sputum
- Unintended weight loss
- Fatigue
- Slight fever
- Night sweats
- Chills
- Loss of appetite
- Pain with breathing or coughing (pleurisy)
Tuberculosis also can target almost any part of your body, including your joints, bones, urinary tract, central nervous system, muscles, bone marrow and lymphatic system.
When TB occurs outside your lungs, signs and symptoms vary, depending on the organs involved. For example, tuberculosis of the spine may result in back pain, and tuberculosis that affects your kidneys might cause blood in your urine. Tuberculosis can also spread through your entire body, simultaneously attacking many organ systems.
