What is tuberculosis?
Tuberculosis (TB) is a chronic bacterial infection that usually infects the lungs, although other organs such as the kidneys, spine, or brain are sometimes involved. TB is primarily an airborne disease.
There is a difference between being infected with the TB bacterium and having active tuberculosis disease.
There are three important ways to describe the stages of TB. They are as follows:
Exposure. This occurs when a person has been in contact with, or exposed to, another person who is thought to have or does have TB. The exposed person will have a negative skin test, a normal chest X-ray, and no signs or symptoms of the disease.
Latent TB infection. This occurs when a person has TB bacteria in his or her body, but does not have symptoms of the disease. The infected person's immune system walls off the TB organisms, and they remain dormant throughout life in 90 percent of people whom are infected. This person would have a positive skin test but a normal chest X-ray.
TB disease. This describes the person who has signs and symptoms of an active infection. The person would have a positive skin test and a positive chest X-ray.
The predominant TB bacterium is Mycobacterium tuberculosis (M. tuberculosis). Many people infected with M. tuberculosis never develop active TB and remain in the latent TB stage. However, in people with weakened immune systems, especially those with HIV (human immunodeficiency virus), TB organisms can overcome the body's defenses, multiply, and cause an active disease.
Who is at risk for developing TB?
TB affects all ages, races, income levels, and both genders. Those at higher risk include the following:
People who live or work with others who have TB
Medically underserved populations
People from other countries where TB is prevalent
People in group settings, such as nursing homes
People who abuse alcohol
People who use intravenous drugs
People with impaired immune systems
Health care workers who come in contact with high-risk populations
What are the symptoms of TB?
The following are the most common symptoms of active TB. However, each individual may experience symptoms differently.
Cough that will not go away
Loss of appetite
Unintended weight loss
Poor growth in children
Coughing blood or sputum
Chills or night sweats
The symptoms of TB may resemble other lung conditions or medical problems. Consult a physician for a diagnosis.
What causes TB?
The TB bacterium is spread through the air when an infected person coughs, sneezes, speaks, sings, or laughs; however, repeated exposure to the germs is usually necessary before a person will become infected. It is not likely to be transmitted through personal items, such as clothing, bedding, a drinking glass, eating utensils, a handshake, a toilet, or other items that a person with TB has touched. Adequate ventilation is the most important measure to prevent the transmission of TB.
How is TB diagnosed?
TB is diagnosed with a TB skin test. In this test, a small amount of testing material is injected into the top layer of the skin. If a certain size bump develops within two or three days, the test may be positive for tuberculosis infection. Additional tests to determine if a person has TB disease include X-rays and sputum tests.
TB skin tests are suggested for those:
In high-risk categories.
Who live or work in close contact with people who are at high risk.
Who have never had a TB skin test.
For skin testing in children, the American Academy of Pediatrics recommends:
If the child is thought to have been exposed in the last five years.
If the child has an X-ray that looks like TB.
If the child has any symptoms of TB.
If the child comes from a country where TB is prevalent.
Yearly skin testing:
For children with HIV.
For children who are in detention facilities.
Testing every two to three years:
For children who are exposed to high-risk people.
Consider testing in children from ages 4 to 6 and 11 to 16:
If the child's parent has come from a high-risk country.
If the child has traveled to high-risk areas.
If the child lives in a densely-populated area.