Tuberculosis

Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain. If not treated properly, TB disease can be fatal.

TB spreads through the air when a person with TB of the lungs or throat coughs, sneezes, or talks. TB is not spread by shaking someone's hand, sharing food or drink, touching bed linens or toilet seats, sharing toothbrushes, or kissing.

Your body may harbor the bacteria that cause TB, but you may not get sick. For this reason, there are two distinct types of TB: latent TB and active TB. In latent TB, you have a TB infection, but the bacteria remain in your body in an inactive state and cause no symptoms. Latent TB, also called inactive TB or TB infection, is not contagious. It can turn into active TB, so treatment is important for the person with latent TB and to help control the spread of TB in general. Active TB makes you sick and can spread to others. It can occur in the first few weeks after infection with the TB bacteria, or it might occur years later. You are more likely to contract TB, and have an active form of the disease, if you have a weak immune system.

Many strains of tuberculosis resist the drugs most used to treat the disease. People with active tuberculosis must take several types of medications for many months to eradicate the infection and prevent development of antibiotic resistance.

Skin tests, blood tests, x-rays, and other tests are used to diagnose TB. If not treated properly, TB can be fatal. Usually, TB can be cured by taking several medicines for a long period of time.

Symptoms of active TB in the lungs may include:

• a bad cough that lasts 3 weeks or longer
• weight loss
• loss of appetite
• coughing up blood or mucus
• weakness or fatigue
• fever
• night sweats
• chills
• chest pain, or pain when breathing or coughing

When TB occurs outside your lungs, signs and symptoms vary according to the organs involved. For example, TB of the spine may give you back pain, and TB in your kidneys might cause blood in your urine.

TB is caused by bacteria that spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs, or sings.

Although TB is contagious, it is not easy to catch. You are much more likely to get TB from someone you live with or work with than from a stranger. Most people with active TB who have had appropriate drug treatment for at least two weeks are no longer contagious.

The most commonly used diagnostic tool for TB is a simple skin test, though 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 healthcare professional will check your arm for swelling at the injection site. A hard, raised red bump means you are likely to have TB infection. The size of the bump determines whether the test results are significant.

If you have had a positive skin test, your doctor is likely to order a chest X-ray or a computed tomography (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 TB. CT scans provide more-detailed images than do X-rays.

If your chest X-ray shows signs of TB, your doctor may take samples of your sputum — the mucus that comes up when you cough. The samples are tested for TB bacteria. Sputum samples can also be used to test for drug-resistant strains of TB. This helps your doctor choose the medications that are most likely to work. However, these tests can take four to eight weeks to be completed.

Treatment for TB is a complicated and lengthy process, but it is the only way to cure the disease. During treatment, try to maintain your normal activities and hobbies and stay connected with family and friends.

Your physical health can affect your mental health, and denial, anger and frustration are normal when you must deal with something difficult and unexpected. At times, you may need more tools to deal with these or other emotions. Professionals, such as therapists or behavioral psychologists, can help you develop positive coping strategies.

Medications are the cornerstone of TB treatment. You must take antibiotics for at least six to nine months. The exact drugs and length of treatment depend on your age, overall health, possible drug resistance, the form of TB and the infection's location in the body.

If you have latent TB, you may need to take just one type of TB drug. Active TB will require several drugs at once. The most common medications used to treat tuberculosis include:

• isoniazid
• rifampin (Rifadin, Rimactane)
• ethambutol (Myambutol)
• pyrazinamide

If you have drug-resistant TB, a combination of antibiotics called fluoroquinolones and injectable medications, such as amikacin (Amikin), kanamycin (Kantrex), or capreomycin (Capastat Sulfate), are generally used for 20 to 30 months. However, some types of TB are developing resistance to these medications.

A number of new drugs are being looked at as add-on therapy to the current drug-resistant combination treatment including bedaquiline (Sirturo) and linezolid (Zyvox).

After a few weeks, you will not be contagious and you may start to feel better. It might be tempting to stop taking your TB drugs, but it is crucial that you finish the full course of therapy and take the medications exactly as prescribed by your doctor. Stopping treatment too soon or skipping doses can allow the bacteria that are still alive to become resistant to those drugs, leading to TB that is much more dangerous and difficult to treat. To help people stick with their treatment, a program called directly observed therapy (DOT) is recommended. In this approach, a healthcare worker administers your medication so that you do not have to remember to take it on your own.