How does tuberculosis work

HIV weakens a person's immune system, so it can't fight the TB germs. In the United States, because of stronger control programs, tuberculosis began to decrease again in But it remains a concern. Many tuberculosis strains resist the drugs most used to treat the disease. People with active tuberculosis must take many types of medications for months to get rid of the infection and prevent antibiotic resistance.

Although your body can harbor the bacteria that cause tuberculosis, your immune system usually can prevent you from becoming sick. For this reason, doctors make a distinction between:.

Tuberculosis can also affect other parts of your body, including the kidneys, spine or brain. When TB occurs outside your lungs, signs and symptoms vary according to the organs involved. For example, tuberculosis of the spine might cause back pain, and tuberculosis in your kidneys might cause blood in your urine.

See your doctor if you have a fever, unexplained weight loss, drenching night sweats or a persistent cough. These are often indications of TB but can also result from other conditions.

Also, see your doctor if you think you've been exposed to TB. The Centers for Disease Control and Prevention recommends that people who have an increased risk of tuberculosis be screened for latent TB infection.

This recommendation includes people who:. Tuberculosis is caused by bacteria that spread from person to person through microscopic droplets released into the air.

However, they may develop TB disease in the future. They are often prescribed treatment to prevent them from developing TB disease. People with TB disease are sick from TB bacteria that are active, meaning that they are multiplying and destroying tissue in their body.

They usually have symptoms of TB disease. People with TB disease of the lungs or throat are capable of spreading their illness to others. They are prescribed drugs that can treat TB disease. For persons who have weakened immune systems, that risk is much higher than people with normal immune systems. People who develop TB disease have symptoms based on where in the body the TB bacteria are growing.

People can be tested to see if they have TB infection weeks after they are initially infected. People with only TB infection are unlikely to have any symptoms. If infected, people may develop to TB disease at anytime during their lifetime or not at all. There is not a standard time period in which this happens, but is dependent on other conditions a person has that could weaken their immune systems and allow TB disease to develop.

Some people develop TB disease soon within weeks after becoming infected, before their immune system can fight the TB bacteria. Other people may get sick years later, when their immune system becomes weak for another reason. Many people with TB infection never develop TB disease. The following are the stages of TB: 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 his or her body, but does not have symptoms of the disease.

The infected person's immune system walls off the TB organisms, and the TB remains inactive throughout life in most people who are infected.

This person would have a positive skin test, but a normal chest X-ray. TB disease. This describes the person who has signs and symptoms of an active infection. The person would have a positive skin test and a positive chest X-ray. What causes TB? Who is at risk for TB? However, each person may experience symptoms differently: Cough that lasts 3 weeks or longer Chest pain Fatigue Loss of appetite Unintended weight loss Poor growth in children Fever Coughing blood or sputum Chills or night sweats The symptoms of TB may look like other lung conditions or medical problems.

How is TB diagnosed? TB skin tests are suggested for those: In high-risk categories Who live or work in close contact with people who are at high risk Who have never had a TB skin test For skin testing in children, the American Academy of Pediatrics recommends testing: If the child is thought to have been exposed in the last 5 years If the child has an X-ray that looks like TB If the child has any symptoms of TB If the child comes from a country where TB is prevalent For children 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?

Your healthcare provider will figure out the best treatment for you based on: How old you are Your overall health and past health How sick you are How well you can handle specific medicines, procedures, or therapies How long the condition is expected to last Your opinion or preference Treatment may include: Short-term hospitalization For latent TB which is newly diagnosed: Usually a 6 to 12 month course of antibiotic called isoniazid will be given to kill off the TB organisms in the body.

Some people with latent TB may be treated with a shorter course of 2 antibiotics for only 3 months. In the United States, TB is much less common. TB can almost always be treated and cured if you take medicine as directed. Who Is at Risk of TB? This includes: Family and friends of a person who is infected People from parts of the world with high TB rates, including India and parts of Asia and Africa. People in groups with high rates of TB transmission, including the homeless, injection drug users and people living with HIV People who work or reside in facilities that house high risk people such as hospitals, homeless shelters, correctional facilities, nursing homes and residential homes for those with HIV Not everyone who is infected with the TB germ latent TB develops clinically active TB disease.

Previous: Tuberculosis TB. Next: Tuberculosis Symptoms and Diagnosis. Make a Donation Your tax-deductible donation funds lung disease and lung cancer research, new treatments, lung health education, and more.

Make a Donation.