MEDICAL SURFARI: TUBERCULOSIS STRAIN MAKES A COMEBACK

An old foe is making a comeback. Definite signs of a new and potentially very dangerous epidemic of tuberculosis (TB) have already appeared.

TB is a chronic, recurrent infection most common in the lungs, but any organ or tissue may be affected. Once an infection is established, signs and symptoms may develop within months or it may be delayed for years or even decades. With the onset of the AIDS epidemic, the incidence of TB has increased alarmingly among persons infected with HIV, particularly black and Hispanic IV drug users. Blacks are less resistant to the initial invasion by the organism than whites; partly accounting for the greater prevalence of infection among blacks. People with competent immune systems are often able to resist a TB infection while those with weak immune systems may experience progression of the disease.

Tuberculosis is believed to cause more deaths each year than any other infectious disease. It is estimated that 1.7 billion people worldwide are infected with TB and there are an estimated 10-15 million people in the United States with this disease. TB has become a major public health concern again as new strains have developed in the last 10 years that are multidrug-resistant. As the organism becomes resistant to certain drugs, TB can no longer be treated with those drugs, increasing the possibility that the infection cannot be controlled.

Only people with active TB are contagious and the disease is generally spread by microscopic droplets dispersed in the air when someone with active TB coughs or sneezes. These microscopic droplets containing TB organisms may be inhaled by other people, settling into the lungs where they may multiply and establish infection.

Pulmonary TB is often so nearly asymptomatic that a patient may deny all symptoms except "not feeling well." A cough is the most common symptom but it is often ascribed to smoking or recent upper respiratory infection. The cough is usually minimally productive of yellow or green mucus and as the disease progresses, this becomes more productive. The clinical course of TB varies greatly, depending upon multiple factors. Usually, diagnosis is made by a tuberculin tine skin test and chest X-ray.

Successful treatment of TB usually requires a combination of several drugs for at least six months. Once an individual has been treated for at least two weeks with appropriate drugs, they are usually not infectious. Multidrug-resistant TB may require medical treatment for as long as two years.

Most people infected with TB never develop full-blown active TB disease. On average, infected people have about a 10 percent chance of developing active TB sometime during their lives and this chance is increased in individuals whose immune systems are weakened by other diseases or HIV infections, thereby allowing the TB organisms to overcome the body's defenses.

If you have been in close contact with someone diagnosed with active TB or if you have other disease symptoms and have developed respiratory symptoms and productive cough, see your family physician.

World Wide Web Resources

Facts About -- Tuberculosis

www.pbs.org/ppol/ala.html

This Web page from the American Lung Association provides comprehensive, current information on tuberculosis.

The Doctor's Office

www.allkids.org/Epstein/Articles/Tuberculosis.html

There is an excellent article in this Web site called "Tuberculosis -- An Old Enemy Attempts a Comeback!"

Med Facts

njc.org/MFhtml/TUB_MF.html

The National Jewish Medical and Research Center provides a good fact sheet on tuberculosis in the Web site.

Dr. Scott Gibbs is a Cape Girardeau neurosurgeon and editor-in-chief of Mosby's Medical Surfari. You may e-mail questions to him at drgibbs@semissourian.com or write in care of the Southeast Missourian, P.O. Box 699, Cape Girardeau, Mo., 63702.