Tuberculosis, or TB, once the leading cause of death in the United States, is a serious disease that takes the lives of approximately 2 million people worldwide, according to the Centers for Disease Control and Prevention. The World Health Organization estimates that one third of the population is infected with the tuberculosis bacterium and efforts are in place to stop the spread of this deadly disease.
Identification
Tuberculosis is an infection by Mycobacterium tuberculosis. The disease is contagious and spreads when individuals with active TB cough, sneeze, or talk, expelling the bacilli germs through the air. TB is classified into two categories, latent and active TB (TB disease). Individuals with latent TB are infected with the bacteria, but the immune system is preventing further growth and no symptoms are present. Individuals are not infectious during this stage of the disease. However, if the immune system is unable to control bacterial growth, the bacterium multiples and TB disease develops. Individuals with TB disease are infectious and show the signs and symptoms of the disease.
Symptoms
With active TB disease, symptoms vary depending on where the bacterium is growing; the lungs are the most common location (pulmonary TB). With pulmonary TB, symptoms include a cough lasting greater than 3 weeks, chest pain, and the coughing up of blood or sputum. Other symptoms associated with TB include fatigue, decreased appetite, unexplained weight loss, chills, fever, and night sweats.
Risk Factors
According to the World Health Organization, approximately 5% to 10% of individuals who do not receive treatment for latent TB develop TB disease. High-risk individuals include those who have recently been infected with the tuberculosis bacterium and individuals with weakened immune systems. HIV infection, substance abuse, silicosis, diabetes, severe kidney disease and low body weight all weaken the immune system and put individuals at a higher risk of developing TB disease. TB is the leading cause of death in individuals with HIV.
Diagnosis
The first step in diagnosing TB is to determine if an individual has been infected with the TB bacterium with the Mantoux TB skin test. A small amount of tuberculin is injected into the skin of the arm and observed 48 to 72 hours later by a trained professional to determine if a reaction to the tuberculin has occurred. Tuberculin is the name of extracts taken from Mycobacterium tuberculosis that do not cause the disease, but evoke an immune response if an individual is infected with TB. A positive TB skin test only confirms infection, not whether the disease is active or not. A chest x-ray or sputum histological or bacteriologic exam must be performed to determine if active TB disease is present.
Treatment
Tuberculosis is a treatable disease, but the full course of therapy must be completed and followed exactly as prescribed. Treatment of latent TB is aimed at preventing the disease from developing into active TB disease. A single drug is typically prescribed for a 9-month long regimen that works to kill the bacteria in the body. When active TB disease is present, multiple drugs are prescribed over a period of 6 to 12 months. However, drug resistance is a problem as is typical when treating bacterial infections.
