Tuberculosis (TB) is a potentially serious infectious disease that primarily affects your lungs. The bacteria that cause tuberculosis are spread from person to person through tiny droplets released into the air via coughs and sneezes.
Tuberculosis was once rare in developed countries, but the number of TB cases began increasing in 1985. Part of the increase was caused by the emergence of HIV, the virus that causes AIDS. HIV weakens a person's immune system so it can't fight the TB germs.
Many strains of tuberculosis can resist the effects of the drugs most commonly used to treat the disease. People who have active tuberculosis must take several different types of medications together for many months to eradicate the infection and prevent development of antibiotic resistance.
Although your body may harbor the bacteria that cause tuberculosis, your immune system usually can prevent you from becoming sick. For this reason, doctors make a distinction between:
Signs and symptoms of active TB include:
What organs are affected?
But tuberculosis can also affect other parts of your body, including your kidneys, spine or brain. When TB occurs outside your lungs, 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.
When to see a doctor
Tuberculosis 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 tuberculosis is contagious, it's not especially easy to catch. You're much more likely to get tuberculosis from someone you live with or work with than from a stranger. Most people with active TB who've had appropriate drug treatment for at least two weeks are no longer contagious.
HIV and TB
Infection with HIV suppresses the immune system, making it difficult for the body to control TB bacteria. As a result, people with HIV are many times more likely to get TB and to progress from latent to active disease than are people who aren't HIV-positive.
Anyone can get tuberculosis, but certain factors can increase your risk of the disease. These factors include:
Weakened immune system
Poverty and substance abuse
Where you work or live
Without treatment, tuberculosis can be fatal. Untreated active disease typically affects your lungs, but it can spread to other parts of the body through your bloodstream. Examples include:
Preparing for your appointment
If you suspect that you have tuberculosis, contact your family doctor or your state health department. You may be referred to a doctor who specializes in infectious disease or lung diseases (pulmonologist).
What you can do
What to expect from your doctor
Tests and diagnosis
During the physical exam, your doctor will check your lymph nodes for swelling and use a stethoscope to listen carefully to the sounds your lungs make when you breathe.
The most commonly used diagnostic tool for tuberculosis is a simple skin test. 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 TB infection. The size of the bump determines whether the test results are significant.
Results can be wrong
A false-positive test may happen if you've been vaccinated with the bacillus Calmette-Guerin (BCG) vaccine. This tuberculosis vaccine is seldom used in the United States but is widely used in countries with high TB infection rates.
False-negative results may occur in certain populations — including children, older people and people with AIDS — who sometimes don't respond to the TB skin test. A false-negative result can also occur in people who've recently been infected with TB but their immune system hasn't had time to react to the bacteria yet.
Treatments and drugs
Medications are the cornerstone of tuberculosis treatment. But treating TB takes much longer than treating other types of bacterial infections. With tuberculosis, 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 (latent or active) and its location in the body.
Most common TB drugs
Medication side effects
Completing treatment is essential
To help people stick with their treatment, a program called directly observed therapy (DOT) is sometimes recommended. In this approach, a health care worker administers your medication so that you don't have to remember to take it on your own.
If you test positive for latent TB infection, your doctor may advise you to take medications to reduce your risk of developing active tuberculosis. The only type of tuberculosis that is contagious is the active variety, when it affects the lungs. So if you can prevent your latent tuberculosis from becoming active, you won't transmit tuberculosis to anyone else.
Protect your family and friends
Finish your entire course of medication
Coping and support
Undergoing treatment for tuberculosis is a complicated and lengthy process. But the only way to cure the disease is to stick with your treatment. You may find it helpful to have your medication given by a nurse or other health care professional so that you don't have to remember to take it on your own. In addition, try to maintain your normal activities and hobbies, and stay connected with family and friends.
Keep in mind that your physical health can affect your mental health. 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.
Last Updated: 2011-01-26
© 1998-2013 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research.
Terms and conditions of use