Tuberculosis (TB) is an infectious disease affecting mainly the lungs.
TB is the result of infection by Mycobacterium tuberculosis, a type of bacteria. The bacteria spreads when an infected person coughs or sneezes, sending droplets into the air where another person can inhale the bacteria into his lungs.
What is Tuberculosis
There are two general types of TB – latent and active. In latent TB, you have Mycobacterium tuberculosis bacteria in your body, but the bacteria are in an inactive state and are not contagious. The bacteria may become active, however, so latent TB requires treatment.
Active TB can make you sick and it can spread to other people. This type of TB may occur within weeks of infection or it can develop years later.
Healthy people infected with the bacteria do not usually experience symptoms, as the immune system “walls off” the infection to prevent its spread. When symptoms do appear, they can include:
- Coughing, sometimes with blood or sputum
- Chest pain
- Weight loss
- Night sweats
Once a leading cause of death in the United States, TB is much less common now. Less than 10,000 Americans contracted the disease in 2014, according to the Centers for Disease Control and Prevention (CDC).
TB is still one of the world’s deadliest infectious diseases in other countries, however. One-third of the world’s population is infected with the bacteria, and the disease claimed more than 1.5 million lives in 2014.
Doctors use a PPD skin test or a blood test to detect Mycobacterium tuberculosis bacteria in a person’s body. Laboratory testing can detect the bacteria in sputum as well. A chest x-ray or CT scan may show the infection site in the lungs.
A lung doctor may perform a thoracentesis. TB can cause pleural effusion, a condition where fluid accumulates in the pleural space between the lungs and chest wall. This test involves the use of a needle to withdraw some of this fluid for testing.
The goal of TB treatment is to cure the infection. Treatment for TB usually involves a course of medication lasting six months or, in some cases, longer.