TUBERCULOSIS
What is Tuberculosis?
TB is a chronic bacterial infection. It is spread through the air and usually infects the lungs, although other organs are sometimes involved. Most persons that are infected with M. tuberculosis harbor the bacterium without symptoms but many develop active TB diseaseHow do People Catch TB?
TB is primarily an airborne disease. The disease is spread from person to person in tiny microscopic droplets when a TB sufferer coughs, sneezes, speaks, sings, or laughs. Only people with active disease are contagious.
It usually takes lengthy contact with someone with active TB before a person can become infected. On average, people have a 50 percent chance of becoming infected with M. tuberculosis if they spend eight hours a day for six months or 24 hours a day for two months working or living with someone with active TB. However, people with TB who have been treated with appropriate drugs for at least two weeks are no longer contagious and do not spread the germ to others.
What are the Symptoms of TB?
Early symptoms of active TB can include weight loss, fever, night sweats, and loss of appetite, or they may be vague and go unnoticed by the affected individual. One in three patients with TB will die within weeks to months if the disease is not treated. For the rest, their disease either goes into remission (halts) or becomes chronic and more debilitating with cough, chest pain, and bloody sputum.
Symptoms of TB involving areas other than the lungs vary, depending upon the organ affected.
How is TB Diagnosed?
Doctors can identify most people infected with M. tuberculosis with a skin test. They will inject a substance under the skin of the forearm. If a red welt forms around the injection site within 72 hours, the person may have been infected. This doesn't necessarily mean he or she has active disease. Most people with previous exposure to M. tuberculosis will test positive on the tuberculin test, as will some people exposed to bacteria that are related to the TB germ.
If a person has an obvious reaction to the skin test, other methods can help to show if the individual has active TB. In making a diagnosis, doctors rely on symptoms and other physical signs, a person's history of exposure to TB, and x-rays that may show evidence of M. tuberculosis infection.
Can TB be Cured?
With appropriate antibiotic treatment, TB can be cured in more than nine out of ten patients.
Why is it so Important to Finish all of the TB Medicine?
If patients don't take all their medicine the way their doctor tells them, they can become sick again and spread TB to their friends and family. Additionally, when patients do not take all the drugs the doctor has prescribed or skip times when they are supposed to take them, the TB bacteria learn to outwit the TB antibiotics, and soon those medications no longer work against the disease. If this happens, the person now has resistant TB infection.
Some patients have disease that is resistant to two or more drugs. This is called multidrug-resistant TB or MDR-TB because the TB germ, M. tuberculosis resists eradication with more than drug. This form of TB is much more difficult to cure.
Can MDR-TB be Treated?
Treatment for MDR-TB often requires the use of special TB drugs, all of which can produce serious side effects. To cure MDR-TB, patients may have to take several antibiotics, at least three to which the bacteria still respond, every day for up to two years. However, even with this treatment, between four and six out of ten patients with MDR-TB will die, which is the same as for patients with normal TB who do not receive treatment.
How is TB Prevented?
TB is largely a preventable disease. In the United States, doctors try to identify persons infected with M. tuberculosis as early as possible, before they have developed active TB. They will give a drug called isoniazid (INH) to prevent the active disease. This drug is given every day for 6 to 12 months. INH can cause hepatitis in a small percentage of patients, especially those older than 35 years. A nurse may watch the patients take their medicine to make sure all pills are taken.
Hospitals and clinics can take precautions to prevent the spread of TB. Precautions include using ultraviolet light to sterilize the air, special filters, and special respirators and masks. Until they can no longer spread the TB germs, TB patients in hospitals should be isolated in special rooms with controlled ventilation and airflow.
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