What is tuberculosis?
Tuberculosis (TB) is a bacterial infection that often infects the lungs. Other organs
such as the kidneys, spine, or brain may also be affected. TB is mainly spread from
person to person through the air, such as when an infected person coughs or sneezes.
It can also cause an active infection after not being active in someone who was exposed
at an earlier time.
There is a difference between being infected with TB bacteria and having active tuberculosis
The stages of TB are:
Exposure. This happens when a person has been in contact with, or exposed to, another person
who has TB. The exposed person will have a negative skin test, a normal chest X-ray,
and no signs or symptoms of the disease.
Latent TB infection. This happens when a person has TB bacteria in their body but no symptoms of the disease.
The infected person's immune system walls off the TB organisms. And the TB stays inactive
throughout life in most people who are infected. This person would have a positive
skin or blood test for TB but a normal chest X-ray or one that only shows past scarring
from the disease. They would have no signs of active infection in other parts of the
TB disease. This person has signs and symptoms of an active TB infection. The person could have
a positive or negative skin or blood test for TB and a positive chest X-ray, biopsy,
or other finding showing an active infection.
What causes TB?
The main TB bacterium is Mycobacterium tuberculosis (M. tuberculosis). Many people
infected with this bacterium never have active TB. They remain in the inactive (latent)
TB stage. But some will develop active TB anytime from months to years, or even decades,
after being exposed. The chance of developing active TB increases in babies and children
and in older adults. It also increases in people with a weak immune system, especially
those with HIV. Or in those getting medicines that suppress the immune system.
The TB bacterium is spread through the air when an infected person coughs, sneezes,
speaks, sings, or laughs. It's very unlikely to be spread from personal items that
a person with TB has touched. Good ventilation can limit the spread of TB to other
people. But early diagnosis and treatment of the person with active TB is most important.
It's also important to limit other people's exposure. This means using masks and respiratory
Who is at risk for TB?
TB affects all ages, races, income levels, and genders. Those at higher risk include:
People who live or work with others who have TB
Those who can't access healthcare
People from countries where TB is more common
People in group settings, such as nursing homes
People who abuse alcohol
People who use injection drugs
People with a weak immune system, including those who have HIV, cancer, a transplant,
or are taking medicines that suppress the immune system
Very young children and older adults
Healthcare workers who come in contact with high-risk populations
What are the symptoms of TB?
Each person's symptoms may vary. The most common symptoms of active TB include:
The symptoms of TB may look like other lung conditions or health problems. Talk with
a healthcare provider for a diagnosis.
How is TB diagnosed?
TB infection is often diagnosed with a skin or blood test. In the skin test (called
a PPD), a small amount of testing material is injected into the top layer of the skin.
If a certain size bump develops within 2 or 3 days, the test may be positive for TB
infection. A blood test called QuantiFERON may also be used. Other tests that may
be key for diagnosing TB include X-rays and sputum tests.
TB skin or blood tests are suggested for people:
In children, the American Academy of Pediatrics recommends testing:
If the child may have been exposed in the last 5 years
If the child has an X-ray that looks like TB
If the child has any TB symptoms
If the child comes from a country where TB is common
For children living with HIV
For children receiving medicines that suppress the immune system
For children who are in detention facilities
For children who are exposed to high-risk people
If the child's parent has come from a high-risk country
If the child has traveled to high-risk areas
If the child lives in a densely populated area
How is TB treated?
Treatment may vary depending on if you have latent or active TB. Treatment may include:
Short-term hospital stay.
For latent TB. Often a 3- to 9-month course of 1 or 2 antibiotics will be given to kill off the TB
organisms in the body. The most common antibiotics prescribed are isoniazid, rifapentine,
and rifampin. Your healthcare provider can review the treatment options. They may
recommend one as the best option for you, taking into account many factors.
For active TB. Your healthcare provider may prescribe 2 to 4 or more antibiotics in combination for
6 to 9 months or longer. Examples include isoniazid, rifampin, pyrazinamide, and ethambutol.
People often begin to improve within a few weeks of starting treatment. After several
weeks of treatment with the correct medicines, the person is often no longer contagious.
But medicine must be finished for the greatest chance of cure, as prescribed by a
What are possible complications of TB?
If TB of the lung is not treated early or if treatment isn’t followed, long-lasting
(permanent) lung damage can result. TB can also cause infection of the bones, spine,
brain and spinal cord, lymph glands, and other parts of the body. It can damage those
areas and cause short-term (temporary) or permanent symptoms from the damage. Uncontrolled
TB can lead to death. And TB remains one of the leading infectious causes of death
What can I do to prevent TB?
If you will be spending time with anyone with active TB, wear a strongly filtering
face mask. And try not to stay in a small enclosed space with poor ventilation. People
who work in situations where there is a high risk for contact with people infected
with TB should be tested for TB on a routine basis. This includes healthcare and shelter
workers. In countries outside the U.S. where TB is more common, a childhood vaccine
is often given. But it's not clear how well it works.
When should I call my healthcare provider?
Let your healthcare provider know if your symptoms get worse or you get new symptoms.
Key points about tuberculosis
Tuberculosis is a bacterial infection that often infects the lungs.
It may also affect the bones, spine, brain, lymph glands, and other parts of the body.
Being infected with the TB bacteria is not the same as having active tuberculosis
There are 3 stages of TB: exposure, latent, and active disease.
A TB skin test or a TB blood test can often diagnose the infection. But other testing
is also often needed.
Treatment exactly as recommended is needed to cure the disease and prevent its spread
to other people.
Tips to help you get the most from a visit to your healthcare provider:
Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells
At the visit, write down the name of a new diagnosis and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed and how it will help you. Also
know what the side effects are.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that
Know how you can contact your provider if you have questions.