Kids Health Info

TB - tuberculosis

  • Australia has one of the lowest rates of TB infection and TB disease in the world. But TB is very common in some countries. Those most at risk of getting a TB infection or TB disease are people whose immune system is weak. It is much harder for a healthy person to get a TB infection or TB disease.

    What is TB?

    • TB is a disease caused by bacteria called Mycobacterium tuberculosis.
    • TB spreads through the air but it is not easy to catch.
    • In 70% of cases TB affects the lungs. But it can also affect other parts of the body, such as the lymph glands, brain, kidneys, or spine.
    • It is more common for children to have TB that affects more than one part of the body, and for the TB to be more serious, than it is for adults.

    A person with TB disease can be successfully treated by taking the full course of antibiotics.

    What is the difference between TB infection and TB disease?

    People can have TB infection but will not necessarily become sick with TB disease

    TB infection

    • People with TB infection have the TB bacteria in their bodies, but their immune system is strong enough to contain the bacteria and stop it from spreading. This means the bacteria can remain inactive for many years.
    • People with TB infection have no symptoms of TB disease and don't feel sick. They are not contagious.
    • There is a risk the TB bacteria will become active at a later stage and cause TB disease, especially in those with weakened immune systems.
    • Children with TB infection have a higher chance of developing active TB disease because their immune system is not as developed as an adult's immune system.

    TB disease

    • In TB disease, the body is no longer strong enough to keep the TB bacteria under control.
    • The bacteria is spreading and causing symptoms of TB (listed below)
    • People with TB disease of the lungs or throat are capable of infecting others, but children with TB disease are not usually contagious.

    Symptoms of TB disease

    • General symptoms of TB disease include: fever, tiredness, sweating at night time and weight loss.
    • Symptoms of TB disease in the lungs include: coughing and chest pain.
    • Symptoms of TB disease in other parts of the body depend on the affected area. The symptoms can be quite varied. Some children with TB disease have no symptoms at all.

    How do we test for TB?

    Mantoux test (tuberculin skin test)

    • A skin (scatch) test is done to see whether the person has been exposed to the TB bacteria.
    • A small amount of fluid is injected into the skin (on the forearm) through the scratch.
    • A doctor looks at the skin test 2-3 days later to see if there has been a reaction (swelling in the skin)

    Quantiferon Gold blood test

    • This blood test measures how a person's immune system reacts to bacteria that cause TB, and is used to see if the body has been infected with TB.

    Both the skin and blood tests tell us if a person has been infected with TB. But, they do not tell us if the person has active TB disease. Further testing is then needed to find out if the TB is active, including a thorough examination by a doctor, chest x-rays, and sputum samples.

    How do we treat TB?

    TB infection

    TB is treated with antibiotics. A person with a TB infection must take the antibiotics for at least six months to kill the bacteria and prevent TB disease. Usually one type of antibiotic is needed.

    TB disease

    TB disease is also treated with antibiotics. But treatment is usually with four different types of antibiotics which have to be taken together for two months, and then two antibiotics (usually Isoniazid and Rifampicin) for a further four months:

    • Isoniazid
    • Rifampicin
    • Pyrazinamide
    • Ethembutol

    TB disease outside of the lungs may need longer courses of antibiotics.

    It is very important that all four antibiotics are taken until advised by your doctor. If you stop taking antibiotics before your doctor tells you to, this can make the TB disease resistant to antibiotics and difficult to treat.

    Side effects

    Sometimes these antibiotics can cause side effects. Side effects are less common in children than adults. Side effects include:

    • feeling sick and loss of appetite
    • antibiotics can affect the liver, but this is very rare in children
    • Rifampicin may turn body fluids (urine, tears, saliva) orange, but this is harmless to the body and will disappear when the course of Rifampicin has finished.
    • Ethambutol can cause visual (eye) problems and children on this antibiotic may need regular eye checks. Although this side effect is very rare, if you are concerned about your child's vision you should report it immediately to your doctor or TB nurse.
    • TB antibiotics may interfere with any other medicines your child is taking. This should be discussed with your doctor.

    When to take the antibiotics

    • Isoniazid and Rifampicin work best on an empty stomach. These tablets should be taken 30-45 minutes before a meal, preferably before breakfast.
    • Pyrazinamide and Ethambutol work best when taken with or after a meal.

    For more information



    Developed by the RCH Dept of Respiratory Medicine. First published: December 2010.

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This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital, Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.