Rarity in U.S.
Tuberculosis is a rarity in this country but globally it remains a significant threat. According to the Centers for Disease Control and Prevention, 9.6 million people around the world were diagnosed with the disease in 2014, with 1.5 million cases proving fatal. Almost 2.2 billion people, or one third of the world’s population, are infected with tuberculosis. Most infected people have latent TB, meaning they have the tuberculosis germs in their bodies, but their immune systems protect them from becoming sick. In the U.S., there 9,421 cases of tuberculosis reported in 2014. Tuberculosis infections began increasing in 1985, partly because of the emergence of HIV, the virus that causes AIDS. HIV weakens a person’s immune system so it can’t fight the TB germs. The disease is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs but they can attack any part of the body, including the kidney, spine and brain.
In closed spaces
If not treated, tuberculosis can be fatal. Fortunately, the disease is not easily transmitted. Usually a person has to be close to someone with TB for a long period of time. The bacterial infection is spread through the air, when someone infected coughs, sneezes or speaks. TB is usually spread between family members, close friends, and people who work or live together. TB is spread most easily in closed spaces over a long period of time. It can’t be spread by shaking someone’s hand, touching bed linens or a toilet seat or by sharing food or drink. It is important to understand that there is a difference between being infected with TB and having the disease. Someone who is infected with TB has the TB bacteria, in their body. The body’s immune system is protecting them from the germs and they are not sick. This is referred to as latent TB. Someone with active TB is sick and can spread the disease and needs to see a doctor as soon as possible.
Someone with a latent tuberculosis infection will not display any symptoms and cannot spread the disease to anyone else. In these people, the TB bacteria remain inactive for a lifetime without causing the disease. But in other people, the bacteria become active, multiply and cause TB. The early symptoms of active TB can include weight loss, a cough lasting three or more weeks, fever, night sweats and a loss of appetite. People with a weakened immune system are considered high risks for the disease. This includes babies and young children, whose immune systems have not fully developed, as well as AIDS patients, cancer patients undergoing chemotherapy and organ transplant recipients. Tuberculosis can also affect other parts of your body. When TB occurs outside of your lungs, the symptoms vary according to the organs involved. For example, tuberculosis of the spine may give you back pain, and tuberculosis in your kidneys might cause blood in your urine.
Simple skin test
A simple skin test is commonly used to diagnose tuberculosis, although blood tests are becoming more commonplace. A small amount of a substance called PPD tuberculin is injected just below the skin of your inside forearm. You should feel only a slight needle prick. Within 48 to 72 hours, a health care professional will check your arm for swelling at the injection site. A hard, raised red bump means you’re likely to have a TB infection. The size of the bump determines whether the test results are significant. Unfortunately, this test isn’t perfect. Sometimes, it suggests that people have TB when they really don’t. It can also indicate that people don’t have TB when they really do. If you’ve had a positive skin test, your doctor is likely to order a chest X-ray or a CT scan. This may show white spots in your lungs where your immune system has walled off TB bacteria, or it may reveal changes in your lungs caused by active tuberculosis. CT scans provide more-detailed images than X-rays.
Resistant to drugs
With the appropriate treatment, tuberculosis can be cured in most people. This usually involves taking several antibiotic drugs for at least six months or sometimes for a long as a year. You may only have to stay a short time in the hospital, if at all, and can then continue taking medication at home. After a few weeks you can probably even return to normal activities and not have to worry about infecting others. If you are being treated in a public clinic, you may be asked to take your medicines in the presence of a health care worker who will ensure that you have done so. This is called “directly observed therapy.” It is important that people who have TB are treated, finish their medications and take the drugs as prescribed. If they stop taking the drugs too soon, they can become sick again. If they do not take the drugs correctly, the bacteria that are still alive may become resistant to those drugs. TB that is resistant to drugs is harder and more expensive to treat.
Trusted by thousands of listeners every week, T. Glenn Pait, M.D., began offering expert advice as the host of UAMS’ “Here’s to Your Health” program in 1996. Dr. Pait began working at UAMS in 1994 and has been practicing medicine for over 20 years.