Tuberculosis (TB)

Illustration of the anatomy of the respiratory system, adult

What is TB?

Tuberculosis can be 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 spread in an airborne manner from person to person. It can also cause an active infection after a period of dormancy in someone who was exposed at an earlier time.

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:

  1. 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.

  2. 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 the TB remains dormant throughout life in most people who are infected. This person would have a positive skin test but a normal chest X-ray.

  3. 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

  • Homeless people

  • 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

  • The elderly

  • 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

  • Chest pain

  • Fatigue

  • Loss of appetite

  • Unintended weight loss

  • Poor growth in children

  • Fever

  • Coughing blood or sputum

  • Chills or night sweats

The symptoms of TB may resemble other lung conditions or medical problems. Consult a doctor for a diagnosis.

What causes TB?

The TB bacterium is spread through the air when an infected person coughs, sneezes, speaks, sings, or laughs. 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?

The presence of TB is often 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. There is a blood test that can be done in place of the TB skin test. 

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 testing:

  • 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

  • For children with HIV

  • For children who are in detention facilities

  • For children who are exposed to high-risk people

  • 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

What is the treatment for tuberculosis?

Specific treatment will be determined by your doctor based on:

  • Your age, overall health, and medical history

  • Extent of the disease

  • Your tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the disease

  • Your opinion or preference

Treatment may include:

  • Short-term hospitalization

  • For latent TB which is newly diagnosed: Usually a six- to 12-month course of antibiotic called isoniazid will be given to kill off the TB organisms in the body.

  • For active TB: Your doctor may prescribe three or more antibiotics in combination for a time period of six to nine months or longer. Examples include: isoniazid, rifampin, pyrazinamide, and ethambutol. Patients usually begin to improve within a few weeks of the start of treatment. After several weeks of treatment with the correct medications, the patient is not usually contagious, provided that treatment is carried through to the end, as prescribed by a doctor.

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