Tuberculosis (TB) - Topic Overview

Topic Overview

What is tuberculosis?

Tuberculosis (TB) is a bacterial infection that is most often found in the lungs (pulmonary TB) but can spread to other parts of the body (extrapulmonary TB). TB in the lungs is easily spread to other people through coughing or laughing. Treatment is often successful, though the process is long. Treatment time averages between 6 and 9 months.

Tuberculosis is either latent (dormant) or active.

• Latent TB means that you have the TB-causing bacteria in your body, but you cannot spread the disease to others. However, you can still develop active TB.
• Active TB means the infection is spreading in your body and, if your lungs are infected, you can spread the disease to others.

What causes tuberculosis?

Tuberculosis is caused by Mycobacterium tuberculosis, slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs.

What are the symptoms?

If you have latent TB, you will not have symptoms unless the disease becomes active. Most people don't know that they have latent TB.

Symptoms of active TB may include:

• Ongoing cough that brings up thick, cloudy, and sometimes bloody mucus from the lungs (sputum).
• Fatigue and weight loss.
• Night sweats and fever.
• Rapid heartbeat.
• Swelling in the neck (when lymph nodes in the neck are infected).
• Shortness of breath and chest pain (in rare cases).

Sometimes, when you are first infected, the disease is so mild you don't know you have it. This is also true for people with latent TB because they have no symptoms.

How is TB spread to others?

People who have a latent TB infection cannot spread the disease.

TB in the lungs (pulmonary TB) is contagious. It spreads when a person who has active disease exhales air that contains TB-causing bacteria and another person inhales the bacteria from the air.

TB in other areas outside of the lungs (extrapulmonary TB) cannot spread easily to others.

How is TB diagnosed?

Latent TB is usually found through a tuberculin skin test (also called a TB skin test, PPD test, or Mantoux test) or a blood test. Active TB is diagnosed by finding the TB-causing bacteria in fluid from the lungs (sputum) or in samples from other parts of the body. Doctors sometimes use a chest X-ray to help diagnose active TB.

Extrapulmonary TB is diagnosed by a biopsy and culture, CT scan, or MRI.

How is it treated?

Doctors generally use a combination of four antibiotics to treat active TB, whether it occurs in the lungs or elsewhere. Medications for active TB must be taken for at least 6 months. Almost all people who take their medications as directed are cured. If tests continue to show an active TB infection, treatment is extended for 8 to 9 months.

One antibiotic taken for 9 months is the usual treatment for latent TB. This prevents the infection from becoming active and reduces the risk of complications.

If you miss doses of medication or you stop treatment too soon, your treatment may go on longer or you may have to start over. This can also cause the infection to get worse or lead to antibiotic-resistant infections that are much harder to treat.

A health professional may have to watch you take your medications. This may mean daily visits to a doctor's office or public health facility. Or the health professional may come to your home or workplace. A cure for TB requires you to take all doses of the antibiotics. Direct observational treatment ensures that people follow medication instructions, which is helpful because of the long treatment course for TB. Cure rates for TB have greatly improved because of this treatment practice.

If active TB is not treated, it can damage the lungs or other organs and can possibly cause death.

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