Tuberculosis is a bacterial infection that begins in the lungs. TB is spread through the air when an infected person coughs or sneezes, spreading the bacteria in aerosol droplets. When you are exposed to TB, the bacteria can be destroyed by your immune system and you will not be infected. Your immune system can also contain the infection in your lungs, causing the bacteria to become dormant. This is known as "dormant TB."
Tuberculosis is caused by the mycobacterium tuberculosis bacterium. TB is contagious, but is relatively difficult to acquire. Most people are infected by people they have continued contact with, as opposed to catching it from a brief encounter with a stranger. Only about 1 in 10 people who are exposed to TB actually develop a TB infection.
Tuberculosis destroys the fine cavities in your lungs. Infection causes chest pain, coughing and bloody sputum. Advanced tuberculosis infection can spread to other organs in your body and cause death. Some individuals are able to combat TB infections with their immune systems. TB is treated with antibiotics.
Some people are infected with TB but successfully contain the infection without killing all the TB bacteria. The bacteria go into a state of dormancy. A person with dormant TB will test positive for TB in a skin test, but will not exhibit symptoms of TB. People with dormant TB cannot pass the infection on to other people.
People with dormant TB are apt to develop the infection even years after having dormant TB. There are many triggers that can cause dormant TB to become active and start multiplying. It is likely to be caused by a weakening of your immune system. This occurs naturally with age. Your immune system can also be weakened by drug or alcohol abuse or malnutrition. Chemotherapy can also trigger dormant TB to become active. There are many drugs that can weaken your immune system, including steroids like cortisone (used for prolonged periods) and TNF inhibitors used to treat arthritis.
Test and Treatment
A skin test known as the Mantoux test is given. A small injection is made subcutaneously in your forearm. A few days later, a medical technician will check the injection site for swelling. This indicates if you might have TB or not. If your test is positive, the doctor may order a chest X-ray to confirm TB infection. False positive results can occur if you have a related mycobacterial infection. False negatives occur in individuals with weakened immune systems. There are many drugs that are used to treat dormant and active TB. Some strains of TB have become resistant to drugs and are more difficult to treat.