Pulmonary Tuberculosis (TB) is sometimes known as the disease that never goes away. It still has a high rate of occurrence in particular groups, namely lower income, urban area groups. More specifically, an article in American Family Physician titled ďTuberculosis in AdultsĒ lists 6 high risk groups. They are:
(1) Racial and ethnic minority populations that are medically under served. (2) People that are from countries where there is a high prevalence. (3) People that have been infected by the disease through domestic or occupational contacts. (4) Users of injection drugs or alcohol. (5)Residents and staff of facilities such as nursing homes, hospitals, and other health institutions. (6) Individuals with chronic disease (1994).
America has recently seen an increase in tuberculosis. In 1991, 26,283 new cases were reported, that was almost 10,000 cases more than were anticipated based on earlier trends. Several factors are contributing to this increase, namely adverse social and economic conditions, the increase of HIV infections, immigration of people who have TB infection, and failure to follow recommended procedures for screening and treatment. One other major factor in the current increase of TB is the introduction of certain strains which are resistant to multiple drugs that have been used in the past. In New York City, April 1991, a study was done to test all positive tuberculosis cultures, and it was found that 33 percent were resistant to one or more anti-tuberculosis drugs (Tuberculosis in Adults, 1994).
The pathogenesis, or origination and development of TB, is by infection with an organism called Mycobacterium tuberculosis. This bacterium enters the body primarily through inhaled air. According to Rakel and Conn in the textbook titled Family Practice, millions of organisms are inhaled, and most of them are destroyed by the white blood cells. However, the few that do survive will enter the blood stream and spread to other organs such as liver, spleen and lymph nodes (Marieb & Mallatt, 1996). The lung lymph nodes form a fibrous growth which will calcify over a few years (Guyton & Hall, 1996). The patient may have sweats, fever, and flu-like symptoms early in the process, but these symptoms generally will go away. Only a few people become ill and will remain ill continuously. Tuberculosis bacteria can spread to almost every organ once someone is infected and becomes ill. To have infection in organs other than the lung is called disseminated tuberculosis. When disease is found only in the lung it is called miliary tuberculosis. Both forms can be reactivated over a patientís lifetime, and the probability of doing so is about 90% in adults. Each reactivation carries a risk of the disease becoming more severe, and eventually the disease will become fatal by destroying lung, liver, or other tissues (1978).

Somewhere within two to eight weeks of the initial infection there will be enough antibodies against the bacteria to create a positive TB skin test. The test is performed by placing a small amount of PPD, a protein derivative of Mycobacterium tuberculosis, into a tiny needle and injecting it into the skin. A whelp or a raised skin reaction indicates a positive test and a previous infection with the bacteria. A skin test will be positive for a personís entire life, even if they no longer have active disease (Amin, 1994).
People who have positive skin test only will usually be treated with one anti-tuberculosis drug. The most common drug is Isoniazide, known as INH. Treatment will last for at least six months, sometimes as long as a year. People who have evidence of active disease such as an abnormal chest X-ray, elevated liver enzymes, or who grow fresh Mycobacterium tuberculosis on cultures from their body fluids will be treated with multiple drugs. Most treatment is done with at least three drugs simultaneously. INH, Ethambutal, and Rifampin are often given together and are an example of multiple drug therapy. Treatment can last as long as two years for this group (Rakel & Conn, 1978).
Treatment has been very successful for the last twenty years, but now some strains of this bacteria have become resistant to the common drugs used for treatment. Because this disease has a risk of reactivation over a personís entire life it is important that we find new drugs, both to save an already infected