Tuberculosis, or TB for short, is a bacterial infection caused by Mycobacterium tuberculosis (M. tb). This germ most often damages the lungs but can also infect other organs in the human body.
Call the UPMC Center for Care of Infectious Diseases to learn more or make an appointment at 412-647-7228 or 1-877-788-7228.
TB is a disease that forms when M. tb bacteria infects the body.
M. tb most often affects the lungs but can occur in almost any other organ, such as the:
There are two types of TB infections:
Latent TB occurs when your body "walls off" the infection in the lungs, preventing symptoms.
But with active TB, the infection:
About one in four people in the world have latent TB infection. Most people with latent TB don't develop active disease. In fact, only about one in 10 people with latent TB forms an active TB infection at some point in their life.
The American Lung Association cites that about 10 million people in the world have active TB.
Rates of TB are very low in the U.S. and have been falling for years. The CDC reports 7,174 cases of TB in the U.S. in 2020.
Active TB is contagious, but it doesn't spread from one person to another very easily.
People cannot get TB from:
The bacteria travel through the air when someone with TB talks or coughs. If someone breathes in air particles containing the bacteria, the TB can infect them.
After TB germs enter someone's lungs, they can grow and travel through the bloodstream — and to other organs in the body.
A person with TB can only release TB germs into the air if they have the disease in their lungs or throat. A person with TB in other organs of the body, such as the kidney or brain, can't pass it on to others.
People are at risk for TB infection if they have spent time around someone else with active TB disease. Even after breathing in the bacteria, though, it may take weeks or years for a person to form active disease.
People with latent TB can't spread the disease to others since they can't release the germs into the air. As mentioned before, people with latent TB cannot release bacteria into the air, hence they cannot spread the infection to other individuals.
Those at risk for TB infection of any kind include:
People with latent TB are more likely to get active TB if they have a medical condition that weakens their immune system.
This includes those who:
People with latent TB don't have symptoms or feel sick. But they can develop active TB if they don't receive treatment for their infection.
If a person with active TB disease doesn't receive proper treatment, they can suffer severe complications or even die.
Complications can include:
People with latent TB most often won't have symptoms.
But if you have active TB disease, you'll likely feel sick and have symptoms such as:
You should see your doctor if:
If there's a chance you might have a TB infection, a health care provider will screen you. A TB screening test is a blood or skin test that looks for exposure to TB bacteria within your body.
A positive skin or blood test means TB bacteria has infected you, but you may not have active TB disease. But it cannot tell your doctor if there is a latent or active infection on its own.
Doctors call the TB blood test an IGRA (such as QuantiFERON). We will draw some blood with a needle and send it off to a lab. After a few days, we can tell you if you tested negative or positive.
Doctors call the TB skin test a TST (tuberculin skin test). Other names for the skin test besides TST are Mantoux and purified protein derivative (PPD).
The first step of a skin test is receiving an injection of fluid in the underside of the forearm. After two to three days, you'll return so we can "read" the results by looking at your arm.
A negative test means you don't have TB bacteria in your body. A positive test means you probably do have TB bacteria. If you test positive, your doctor may order a chest x-ray and do other tests to determine if an infection is present.
To test for active TB disease, your doctor will need a sample of your saliva mixed with mucus. They will also need you to get a chest x-ray.
TB without treatment can cause death by damaging the lungs and other organs in your body.
It gets harder for damaged lungs to do their job and can cause fluid to build up. Your lungs can also start to fill with blood.
The more blood and fluid that builds up in the lungs, the harder it is to breathe. If treatment doesn't slow down the bacteria, a person will die from not having enough oxygen.
This is why it's crucial to get treatment for TB.
Your treatment will depend on whether you have latent TB or active TB.
Doctors use three medications to treat latent TB:
Here are some common treatment plans involving the above drug regimens:
Treatment for latent TB is effective and reduces the risk of someone converting to active TB.
Treating active TB disease usually involves two separate stages. The first involves taking four medications for two months:
It's vital to take all these medications exactly as the doctor tells you to. The second stage, called the continuation stage, involves taking isoniazid and rifampin for four months.
Treatment for active TB also cures the disease most of the time.
Some people with TB can form resistance to common TB drugs. This means certain medications can no longer harm the TB bacteria, so doctors must use a new drug the bacteria can't fight.
It's possible to form resistance to one or more TB drugs. Your doctor will guide you in what medicine to take depending on any drug resistance your TB disease has.
If you have drug-resistant TB, it can take longer to cure the disease. For those who may form resistance to several TB drugs, a cure may not be possible.
These are some common side effects of different TB drugs:
To learn more about the UPMC Center for Care of Infectious Diseases or to make an appointment, call 412-647-7228 or 1-877-788-7228.