What Causes Tuberculosis?

Reviewed on 1/12/2021

What is tuberculosis?

Tuberculosis is a bacterial infection that can affect the lungs. People can harbor the bacteria but not exhibit any symptoms.
Tuberculosis is a bacterial infection that can affect the lungs. People can harbor the bacteria but not exhibit any symptoms.

Tuberculosis (TB) is a bacterial infection that usually affects the lungs. It is curable and preventable, but it is also highly contagious

You can be exposed to TB and carry the bacteria in your body but not show any symptoms. Other people get sick from TB and develop significant symptoms like coughing up blood. This will require treatment by a doctor.

Signs or symptoms of tuberculosis

The bacteria that cause TB tuberculosis is called Mycobacterium tuberculosis. They are spread through the air in respiratory droplets. Breathing in the bacteria puts you at risk for TB.  

Some people have TB bacteria in their bodies and never know it. They never develop any symptoms. This is called latent TB. People with latent TB cannot spread the bacteria to anyone else.

Other people develop active TB disease after exposure. This happens when your immune system can’t fight the bacteria effectively and the bacteria start multiplying inside your body. 

The bacteria that cause TB can settle anywhere in your body, including the kidneys and spine. Most commonly, they grow in the lungs and cause the coughing that is associated with the disease.

Symptoms of TB disease in the lungs include:

People with the TB disease in their lungs can spread the bacteria to other people via respiratory droplets. If TB infection is in another part of the body, such as the kidneys, spine, or brain, it is not usually infectious.


 

Causes of tuberculosis

TB is spread by bacteria traveling through the air. If a person with TB disease speaks, sings, coughs, or sneezes, they will project out respiratory droplets containing the bacteria. Other people who breathe in those droplets can get infected. 

TB is not transmitted through touching, kissing, or sharing food or drinks.
 

When to see the doctor for tuberculosis

Because TB is so contagious, you should contact a doctor if you have been in contact with anyone who has active TB disease. You will not be in immediate danger of developing TB disease right after exposure. However, it is essential to be tested and to talk to your doctor about your risk of developing TB disease. 

If you have symptoms of TB disease, such as a cough that lasts more than three weeks, or you have coughed up blood, contact your doctor immediately. You should get tested to confirm TB and start treatment as soon as possible.

Tests for tuberculosis

Your doctor can give you either a skin test or a blood test to check for TB. 

If you were exposed to a person with active TB disease, your doctor will want to know more about that exposure. Your local health department may also want to trace your TB contacts. Contact tracing is a safety precaution to protect other people who might have been exposed. 

If you are showing symptoms of TB disease, your doctor and other health workers will discuss who you may have exposed to the bacteria so they can get tested as well. 

Treatments for tuberculosis 

Many people assume TB is a deadly disease. That was true in the past, but these days it is treatable. Modern antimicrobial drugs make it possible to effectively cure TB today. There are various strategies for combating TB via treatment: 

  1. Active TB disease: If you have active TB disease, your doctor will prescribe a cocktail of drugs that will stop the bacteria from multiplying in your body. You will need to take the medications for 6 to 9 months. You should plan to work closely with your doctor to manage your medication regimen, since it will change during the course of treatment.
  2. Drug-resistant TB: In rare cases, the usual drug regimens aren’t effective. When this happens, it’s called drug-resistant TB. The infection can still be treated, but your medical team will have to monitor you closely to figure out what combination of medicines will work best for you.
  3. Latent TB: If you have latent TB, you may not need treatment right away. The bacteria can live in your body for years and never start multiplying. However, there is always a risk that you could develop symptoms from it.  Latent TB treatment is similar to treatment for active TB disease. Doctors prescribe a combination of drugs that you take for a period of 3 or 4 months, under their supervision.

People with underlying conditions like HIV or diabetes have a higher risk of developing active TB. If you have one of these health concerns, your doctors may decide to treat it before it becomes a problem.

It is essential to follow all instructions from your doctor during treatment for TB.

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References
SOURCES:

Centers for Disease Control and Prevention: "Basic TB Facts."

Centers for Disease Control and Prevention: "Deciding When to Treat Latent TB."

Centers for Disease Control and Prevention: "Drug-Resistant TB."

Centers for Disease Control and Prevention: "Exposure to TB."

Centers for Disease Control and Prevention: "How TB Spreads."

Centers for Disease Control and Prevention: "Treatment for TB Disease."

Centers for Disease Control and Prevention: "Treatment Regimens for Latent TB Infection (LTBI)."

National Center for Biotechnology Information: "Interventions to improve contact tracing for tuberculosis in specific groups and in wider populations: an evidence synthesis."

World Health Organization: "Tuberculosis."

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