Tuberculosis -- Are You at Risk?

April 26, 2007— -- You have not gone out with your friends in months. All of a sudden, you realize, you are too tired to even go to the movies.

You have lost weight without even trying. The constant cough keeps you up at night, but you are used to it by now -- the doctors you have seen could not find anything wrong with you. Could you have been infected with tuberculosis?

Though many consider tuberculosis, or TB, to be a disease of the past, emerging evidence suggests that this infection may present more of a threat than many realize.

In 2005, there were an estimated 8.8 million new cases of TB worldwide, according to the recently released statistics from the World Health Organization. In that same year, 1.6 million people died from the illness.

And as new, drug-resistant strains of TB emerge, many Americans are starting to realize that the threat may not remain confined to the developing nations for much longer.

What is Tuberculosis?

TB is an airborne infection caused by a certain type of bacteria. People who are exposed usually get an infection without symptoms and they are not contagious. This is called "latent tuberculosis."

People with latent tuberculosis are at risk of developing "active tuberculosis" in the future if they do not get treated. Active tuberculosis is the classic disease we think of that causes a bloody cough, fever and weight loss.

Among infectious diseases, TB is the second leading killer of adults in the world. It is also the No. 1 infectious disease killer in persons infected with HIV, the virus that causes AIDS.

Who Is at Risk?

Everyone is at risk of getting infected with tuberculosis, but people with the highest risk of being exposed to TB and developing latent tuberculosis are health care workers and immigrants from countries where TB is common.

It usually takes on average eight hours of contact with someone who has TB to become infected, so infection is often passed around among family members because they spend a lot of time together in the home.

Not everyone who is exposed to TB, however, develops active tuberculosis. Many people in the world (about 2 billion) have been infected with latent tuberculosis, but most of them never develop active tuberculosis. This is due to the fact that an individual's immune system can keep the bacteria in control for years or even a lifetime.

Some people are at a higher risk of getting active tuberculosis, including people with HIV infection, malnourished children and adults, injection drug users, people with diabetes or cancer, and people who received incomplete TB treatment in the past. However, healthy people can get active tuberculosis as well.

What Are the Symptoms?

The most common symptoms of tuberculosis are fever, chills, night sweats, weight loss, fatigue, loss of appetite and coughing up blood.

These symptoms are not specific to tuberculosis because they can occur with many other diseases too. Because of the overlap with other diseases, the diagnosis and therefore the treatment of TB are sometimes delayed.

How Is TB Diagnosed?

If your doctor thinks you may have been exposed to tuberculosis, he or she may do a skin test and have you return to the office in 48 to 72 hours to interpret the test result.

If the test is positive and you do not have symptoms, your doctor will prescribe a course of medications to take for about nine months to treat the latent tuberculosis. This will decrease the chance that you will get active tuberculosis in the future.

If you have some of the symptoms listed above and your doctor thinks you have active tuberculosis, you will need to be in the hospital in an isolated room while doctors test your sputum for tuberculosis bacteria.

You will need to be in isolation for at least three days to perform the preliminary tests for tuberculosis. If the tests are positive, you will need to take medicines for a long time and you may need to stay in isolation (either in the hospital or at home) for a minimum of two weeks while taking the medicines so you are no longer contagious.

Can Tuberculosis Be Cured?

Yes. Treatment for active tuberculosis consists of four drugs to be taken anywhere from four to twelve months or even longer.

The medications are given as direct observed therapy, which means that someone from the local health department comes to the sick person's home or work and watches him or her swallow the pills. This is done because treating tuberculosis correctly and completely is so important.

Unfortunately, foreign countries do not have the resources to observe patients taking the pills, so very few people complete treatment in those countries. As soon as patients feel better, some of them will stop taking the medications thinking they are cured. This is very dangerous because not finishing the full course of medications can cause tuberculosis to become resistant to treatment.

Doctors and scientists have recently discovered multidrug resistant tuberculosis (MDR TB) and extensively multidrug resistant tuberculosis (XDR TB), both of which cannot be treated with regular medications. Even when these patients are treated with the best medications available, half of people with MDR TB, and almost all with XDR TB will die.

So far, these resistant infections have been very rare in the United States. The best way to avoid resistant TB is to make sure that everyone with TB gets the full course of appropriate treatment.

If you or someone you know has been exposed to tuberculosis, or has any of the symptoms discussed above, you should contact your doctor or the local health department to get tested.

The earlier you are diagnosed, the sooner you can get treatment to get well and the lesser the chance of you passing the disease to your family and friends.

Beata Casanas is a doctor of osteopathy, an assistant professor at the University of South Florida College of Medicine, and the executive medical director for the Hillsborough County Health Department.