What is tuberculosis?

Tuberculosis (TB) is a chronic bacterial infection that usually infects the lungs, although other organs 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 3 important ways to describe the stages of TB. They are as follows:

1. Exposure: This occurs when a person has been in contact, or exposed to, another person who is thought to have or does have TB. The exposed person will have a negative skin test, and normal chest x-ray, and no signs or symptoms of the disease.
2. TB infection: This occurs when a person has the TB bacteria in his/her body, but does not have symptoms of the disease. This person would have a positive skin test, but a normal chest x-ray.
3. TB disease: This describes the person that 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). Most people infected with M. tuberculosis never develop active TB. 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.

History of Tuberculosis

During the 19th century, TB claimed more lives in the United States than any other disease. But, with improvements in nutrition, housing, sanitation, and medical care during the first half of the 20th century, the number of cases and deaths dropped dramatically. In the 1940s and 1950s, with the introduction of antibiotic therapies for TB, the decline continued. By 1985, the number of cases had fallen to the lowest figure recorded in modern US history.

However, from 1985 to 1992, the nation experienced a resurgence of TB cases, and a widespread occurrence of multidrug-resistant TB - a serious public health problem in the US. Since, the Centers for Disease Control and Prevention (CDC) has developed and published the National Action Plan to Combat Multidrug-Resistant TB and allocated new resources to put the plan into effect. Among other accomplishments, these efforts have led to improved identification of TB, updated treatment protocols, continued research and education, and upgraded laboratories for early diagnosis and testing.

From 1997 to 1999, there was a 12 percent decline in TB cases, and from 1992 to 1999, there was a 34 percent reduction in TB mortality cases.

Possible Reasons for Resurgence of Tuberculosis Cases

A number of differing factors are cited as the reasons for the increase in cases of tuberculosis:

• the HIV/AIDS epidemic
• increased numbers of immigrants from countries with many cases of TB
• increased poverty, injection-drug use, and homelessness
• poor compliance with treatment regimens

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
• healthcare workers who come in contact with high-risk populations

What are the symptoms of TB?

The following are the most common symptoms for TB. However, each individual may experience symptoms differently.

• cough that will not go away
• fatigue
• loss of appetite
• loss of weight
• fever
• coughing blood
• night perspiring

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; 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, 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.

Recommendations for skin testing in children, from the American Academy of Pediatrics are as follows:

Immediate testing:

• If the child is thought to have been exposed in the last 5 years.
• If the child has an x-ray that looks like TB.
• If the child has any symptoms of TB.
• If a child is coming from countries where TB is prevalent.

Yearly skin testing:

• Children with HIV.
• Children that are in jail.

Testing every 2 to 3 years: is recommended for children who are exposed to high-risk people.

Consider testing in children from ages 4 to 6 and 11 to 16 if:

• a child's parent has come from a high-risk country.
• a child has traveled to high-risk areas.
• the child lives in densely populated areas.

Treatment for tuberculosis:

Specific treatment will be determined by your physician 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
• medications

Treatment may last for many months. However, once the treatment begins, the patient begins to feel well very soon. The patient is not usually contagious once treatment begins, provided that treatment is carried through to the end, as prescribed by a physician.