What is tuberculosis?

Tuberculosis (TB) is a potentially fatal contagious disease that spreads between people via coughs and sneezes. Jorge Parada, medical director of infectious disease at Loyola University Health System, noted that TB is the most common infection in the world and the second leading cause of death due to infectious disease, after HIV/AIDS.

Causes
When a person with untreated TB coughs, sneezes or laughs, he or she can spread bacteria through droplets in the air. Contracting TB typically requires close contact with someone who has TB for an extensive period of time, often in confined quarters. So one is more likely to get TB from a colleague or family member than a stranger.

Someone can be infected with TB (i.e. has the TB germs) but not have TB disease, if the body's immune system protects him or her--a condition known as latent TB. But the immune system can be weakened by AIDS, diabetes, previous TB exposure, drug abuse, chemotherapy, malnutrition, old age or another factor.

TB has spread concomitantly with HIV because each propels the development of the other. The number of TB cases has risen since the 1980s, reports the Mayo Clinic.

Since TB is an infectious disease, your risk of getting it increase if you live or travel in places with high TB rates. Sections of sub-saharan Africa, India, China, Mexico, the former Soviet Union, southeast Asia and Micronesia have high rates of TB, according to the Mayo Clinic.

Symptoms
Latent TB is not contagious and has no symptoms. Once active, TB becomes contagious and can cause weight loss, fevers, chills, fatigue and night sweats. Since TB primarily affects the lungs, the most telling signs involve coughing. Coughing up blood, chest pain, breathing difficulties and persistent coughing are common.

Diagnosis
During a common TB diagnostic skin test, the doctor injects tuberculin into one's forearm. Between two days to three days later, a doctor will see if your arm has a large, hard red bump, which indicates TB infection but not that the disease has transpired. Blood and sputum tests along with a chest X-ray may be necessary to corroborate one's health or illness.

Since blood and skin tests are not perfect, infectious disease specialist Walt Tomford, noted, "A complete history and physical exam is a bedside diagnostician's best clinical tool."

Treatment
The American Lung Association reports that people with latent TB will receive preventative therapy. The most common therapy of this kind is a six to nine month daily dose of isoniazid (INH). Tomford emphasized the importance of proceeding past denial and taking the prescribed medicine for latent TB so it doesn't evolve into active TB.

Those with active TB will be prescribed a combination of various medicines for between six and 12 months. Keeping up with proper drug intake is of the utmost importance because if one lapses, and TB comes back it may be drug resistant. This will make it much more difficult to cure. Multi-drug resistant TB is particularly lethal.