Tuberculosis

Tuberculosis (“TB”) is a contagious bacterial infection caused by Mycobacterium tuberculosis. This disease primarily and most commonly involves the lungs, but can spread to other organs and sites, including the genitourinary tract, central nervous system, lymphatics, eye, small intestine, joints and bone.

TB has been a disease of humans since antiquity. It has been known by many other names including “consumption” (people seemed to be consumed¬† from within), “white plague” (sufferers appeared very pale) and “phthisis” (Greek for consumption).

A person can become infected with the germ by inhaling airborne droplets, produced from a person with active pulmonary TB when they cough, sneeze or spit. A single sneeze can release tens of thousands of bacteria into the air. Once airborne, so-called droplet nuclei may remain respirable for hours, depending upon the environment. The more prolonged, intense, or frequent the exposure, the greater one’s risk of contracting TB.

Tuberculous infection is very common- one-third of the world’s population has been infected and new infections occur at a rate of one per second. Most (90%) of those becoming infected develop “latent” TB (LTBI), an asymptomatic¬† and non-infectious state. Only about 1 in 10 of those with latent TB will go on to develop active (and infectious) disease. It takes at least 3-4 weeks before an infected individual can become infectious. In most cases, however, the germ remains dormant for years before “reactivation.”

Those at higher risk for active disease include the elderly, infants, and those with a weakened immune system, such at those with HIV/AIDS, cancer patients on chemotherapy, organ transplant recipients taking anti-rejection medication. The risk for contracting TB increases if you: (1) are in frequent contact with someone with TB; (2) have poor nutrition; (3) are an alcoholic; (4) have silicosis; (5) have diabetes mellitus; (6) abused intravenous drugs; or (7) live or work in crowded and unsanitary conditions.

Classic symptoms of active TB include cough, coughing up blood, fever, night sweats, fatigue and weight loss. The diagnosis usually relies on tuberculin (PPD) skin testing, chest x-ray,blood tests, and microscopic examination and microbiological culture of sputum (or sometimes other bodily fluid).

Treatment of active TB typically involves taking a combination of 3-4 drugs until your doctor determines the best regimen based on the drug sensitivity of the TB germ infecting you. Some cases are sensitive to all our medicines, while others can be rather resistant. The treatment continues for 6-9 months in most cases and you are usually unable to spread the disease to others after about 2 weeks. While on these medicines, your doctor will monitor you for complications of disease and side effects of treatment. Compliance with the prescribed regimen is very important, as resistance can develop if medications are not taken regularly.

You should call your doctor (1) if you have been exposed to someone with TB, (2) you develop symptoms of TB, (3) your symptoms persist despite treatment, or (4) you develop new symptoms. Generally, the prognosis for pulmonary TB is good if diagnosed early and treatment initiated quickly.

References:

World Health Organization (WHO)

Centers for Disease Control (CDC)

Health Protection Agency (of the UK)