Tuberculosis

  Information from CDC

Table of Contents

Introduction

What is TB?
How is TB spread?
What is latent TB infection?
What is TB disease?

Latent TB Infection  

How can I get tested for TB?  
What if I have been vaccinated with BCG?
 
If I have latent TB infection, how can I keep from developing TB disease?
What if I have HIV infection?

TB Disease

How is TB disease treated?
What are the side effects of drugs for TB?
Why do I need to take TB medicine regularly?
How can I remember to take my medicine?
How can I keep from spreading TB?
What is multidrug-resistant TB?

Introduction


For definitions of common terms related to TB, see the glossary at the end of this document.
 

What is TB?
TB, or tuberculosis, is a disease caused by bacteria called Mycobacterium tuberculosis.  The bacteria can attack any part of your body, but they usually attack the lungs.  TB disease was once the leading cause of death in the United States.

In the 1940s, scientists discovered the first of several drugs now used to treat TB.  As a result, TB slowly began to disappear in the United States.  But TB has come back.  Between 1985 and 1992, the number of TB cases increased. The country became complacent about TB and funding of TB programs was decreased.  However, with increased funding and attention to the TB problem, we have had a steady decline in the number of persons with TB.  But TB is still a problem; more than 16,000 cases were reported in 2000 in the United States.

TB is spread through the air from one person to another.  The bacteria are put into the air when a person with TB disease of the lungs or throat coughs or sneezes.  People nearby may breathe in these bacteria and become infected.

People who are infected with latent TB do not feel sick, do not have any symptoms, and cannot spread TB.  But they may develop TB disease at some time in the future.  People with TB disease can be treated and cured if they seek medical help.  Even better, people who have latent TB infection but are not yet sick can take medicine so that they will never develop TB disease.

This document answers common questions about TB.  Please ask your doctor or nurse if you have other questions about latent TB infection or TB disease.

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How is TB spread?
TB is spread through the air from one person to another.  The bacteria are put into the air when a person with TB disease of the lungs or throat coughs or sneezes.  People nearby may breathe in these bacteria and become infected.

When a person breathes in TB bacteria, the bacteria can settle in the lungs and begin to grow.  From there, they can move through the blood to other parts of the body, such as the kidney, spine, and brain.

TB in the lungs or throat can be infectious.  This means that the bacteria can be spread to other people.  TB in other parts of the body, such as the kidney or spine, is usually not infectious.

People with TB disease are most likely to spread it to people they spend time with every day.  This includes family members, friends, and coworkers.

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What is latent TB infection?
In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing.  The bacteria become inactive, but they remain alive in the body and can become active later.  This is called latent TB infection.  People with latent TB infection

  • have no symptoms
  • don't feel sick
  • can't spread TB to others
  • usually have a positive skin test reaction 
  • can develop TB disease later in life if they do not receive treatment for latent TB infection 

Many people who have latent TB infection never develop TB disease.  In these people, the TB bacteria remain inactive for a lifetime without causing disease.  But in other people, especially people who have weak immune systems, the bacteria become active and cause TB disease.

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What is TB disease?
TB bacteria become active if the immune system can't stop them from growing.  The active bacteria begin to multiply in the body and cause TB disease.  Some people develop TB disease soon after becoming infected, before their immune system can fight the TB bacteria.  Other people may get sick later, when their immune system becomes weak for some reason.

Babies and young children often have weak immune systems.  People infected with HIV, the virus that causes AIDS, have very weak immune systems.  Other people can have weak immune systems, too, especially people with any of these conditions

  • substance abuse
  • diabetes mellitus
  • silicosis
  • cancer of the head or neck
  • leukemia or Hodgkin's disease
  • severe kidney disease
  • low body weight
  • certain medical treatments (such as corticosteroid treatment or organ transplants)

Symptoms of TB depend on where in the body the TB bacteria are growing.  TB bacteria usually grow in the lungs.  TB in the lungs may cause

  • a bad cough that lasts longer than 2 weeks
  • pain in the chest
  • coughing up blood or sputum (phlegm from deep inside the lungs)

Other symptoms of TB disease are

  • weakness or fatigue
  • weight loss
  • no appetite
  • chills
  • fever
  • sweating at night
Difference Between Latent TB Infection and TB Disease
Latent TB Infection TB Disease
  • Have no symptoms
  • Do not feel sick
  • Cannot spread TB to others
  • Usually have a positive skin test
  • Chest x-ray and sputum test normal
  • Symptoms include
    • a bad cough that lasts longer than 2 weeks
    • pain in the chest
    • coughing up blood or sputum
    • weakness or fatigue
    • weight loss
    • no appetite
    • chills
    • fever
    • sweating at night
  • May spread TB to others
  • Usually have a positive skin test
  • May have abnormal chest x-ray, and/or positive sputum smear or culture

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Latent TB Infection

How can I get tested for TB?
A TB skin test is the only way to find out if you have latent TB infection. You can get a skin test at the health department or at your doctor's office. You should get tested for TB if:

  • you have spent time with a person with known or suspected to have TB disease
  • you have HIV infection or another condition that puts you at high risk for TB disease
  • you think you might have TB disease
  • you are from a country where TB disease is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia)
  • you inject drugs
  • you live somewhere in the U.S. where TB disease is more common (homeless shelters, migrant farm camps, prisons and jails, and some nursing homes)

A health care worker can give you the TB skin test. The health care worker will inject a small amount of testing fluid (called tuberculin) just under the skin on the lower part of your arm.  After 2 or 3 days, the health care worker will measure your reaction to the test. You may have a small bump where the tuberculin was injected. The health care worker will measure this bump and tell you if your reaction to the test is positive or negative. A positive reaction usually means that you have latent TB infection.

If you have a positive reaction to the skin test, your doctor or nurse may do other tests to see if you have TB disease. These tests usually include a chest x-ray and a test of the phlegm you cough up. Because the TB bacteria may be found somewhere besides your lungs, your doctor or nurse may check your blood or urine, or do other tests. If you have TB disease, you will need to take medicine to cure the disease.

If you have recently spent time with someone with infectious TB, your skin test reaction may not be positive yet. You may need a second skin test 10 to 12 weeks after the last time you spent time with the infectious person. This is because it can take several weeks after infection for your immune system to be able to react to the TB skin test. If your reaction to the second test is negative, you probably do not have latent TB infection.

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What if I have been vaccinated with BCG?
BCG is a vaccine for TB. This vaccine is not widely used in the United States, but it is often given to infants and small children in other countries where TB is common. BCG vaccine does not always protect people from TB.

If you were vaccinated with BCG, you may have a positive reaction to a TB skin test. This reaction may be due to the BCG vaccine itself or to latent TB infection. But your positive reaction probably means that you have latent TB infection if:

  • you recently spent time with a person who has TB disease
  • you are from an area of the world where TB disease is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia)
  • you spend time where TB is common (homeless shelters, drug-treatment centers, health care clinics, jails, prisons)

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If I have TB infection, how can I keep from developing TB disease?
Many people who have latent TB infection never develop TB disease. But some people who have latent TB infection are more likely to develop TB disease than others. These people are at high risk for TB disease. They include:

  • people with HIV infection
  • people who became infected with TB bacteria in the last 2 years
  • babies and young children
  • people who inject drugs
  • people who are sick with other diseases that weaken the immune system
  • elderly people
  • people who were not treated correctly for TB in the past

If you have latent TB infection (a positive skin test reaction) and you are in one of these high-risk groups, you need to take medicine to keep from developing TB disease. This is called treatment for latent TB infection. There are many treatment options. You and your health care provider must decide which treatment is best for you.

The medicine usually used for the treatment of latent TB infection is a drug called isoniazid or INH. INH kills the TB bacteria that are in the body. If you take your medicine as prescribed, treatment for latent TB infection will keep you from ever developing TB disease.

Most people must take INH for at least 6 to 9 months. Children and people with HIV infection may need to take INH for a longer time.

Sometimes people are given treatment for latent TB infection even if their skin test reaction is not positive. This is often done with infants, children, and HIV-infected people who have recently spent time with someone with infectious TB disease. This is because they are at very high risk of developing serious TB disease soon after they become infected with TB bacteria.

It is important that you take all the pills prescribed for you so that your treatment for latent TB infection is effective. If you start taking INH, you will need to see your doctor or nurse on a regular schedule. He or she will check on how you are doing. Very few people have serious side effects to INH. However, if you have any of the following side effects, call your doctor or nurse right away:

  • no appetite
  • nausea
  • vomiting
  • yellowish skin or eyes
  • fever for 3 or more days
  • abdominal pain
  • tingling in the fingers and toes

Warning: Drinking alcoholic beverages (wine, beer, and liquor) while taking INH can be dangerous. Check with your doctor or nurse for more information.

People who have latent TB infection but do not receive treatment for latent TB infection need to know the symptoms of TB. If they develop symptoms of TB disease later on, they should see a doctor right away.

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What if I have HIV infection?
A person can have latent TB infection for years without any signs of disease. But if that person's immune system gets weak, the infection can quickly turn into TB disease. Also, if a person who has a weak immune system spends time with someone with infectious TB, he or she may become infected with TB bacteria and quickly develop TB disease.

Because HIV infection weakens the immune system, people with latent TB infection and HIV infection are at very high risk of developing TB disease. All HIV-infected people should be given a TB skin test to find out if they have latent TB infection. If they have latent TB infection, they need treatment for latent TB infection as soon as possible to prevent them from developing TB disease. If they have TB disease, they must take medicine to cure the disease.

TB disease can be prevented and cured, even in people with HIV infection.

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TB Disease

How is TB disease treated?
There is good news for people with TB disease! TB disease can almost always be cured with medicine. But the medicine must be taken as the doctor or nurse tells you.

The most common drugs used to fight TB are:

  • isoniazid (INH)
  • rifampin
  • pyrazinamide
  • ethambutol
  • streptomycin

If you have TB disease, you will need to take several different drugs. This is because there are many bacteria to be killed. Taking several drugs will do a better job of killing all of the bacteria and preventing them from becoming resistant to the drugs.

If you have TB of the lungs or throat, you are probably infectious. You need to stay home from work or school so that you don't spread TB bacteria to other people. After taking your medicine for a few weeks, you will feel better and you may no longer be infectious to others. Your doctor or nurse will tell you when you can return to work or school.

Having TB should not stop you from leading a normal life. When you are no longer infectious or feeling sick, you can do the same things you did before you had TB. The medicine that you are taking should not affect your strength, sexual function, or ability to work. If you take your medicine as your doctor or nurse tells you, the medicine will kill all the TB bacteria. This will keep you from becoming sick again.

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What are the side effects of drugs for TB?
Medicine for TB is relatively safe. Occasionally, the drugs may cause side effects. Some side effects are minor problems. Others are more serious. If you have a serious side effect, call your doctor or nurse immediately. You may be told to stop taking your medicine or to return to the clinic for tests.

The side effects listed below are serious. If you have any of these symptoms, call your doctor or nurse immediately:

  • no appetite
  • nausea
  • vomiting
  • yellowish skin or eyes
  • fever for 3 or more days

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Disclaimer: This information is intended as a guide only.   This information is offered to you with the understanding that it not be interpreted as medical or professional advice.  All medical information needs to be carefully reviewed with your health care provider.