Tuberculosis (TB)

  • Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. In 70 per cent 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 multiple parts of the body than it is for adults, and TB is likely to be more serious in children.

    Australia has one of the lowest rates of TB in the world; however, TB is very common in some countries. TB spreads through the air, but it is not easy to catch. Those most at risk of getting TB are people with weakened immune systems.

    TB can be successfully treated by taking the full course of antibiotics as prescribed by a doctor.

    What is the difference between TB infection and TB disease?

    People can have TB infection, but they 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.

    TB disease

    • In TB disease, the body is no longer strong enough to keep the TB bacteria under control.
    • The bacteria spread and cause symptoms of TB (see below).
    • 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.
    • People with TB disease in the lungs or throat are capable of infecting others by coughing droplets of the bacteria into the air; however, children with TB disease are not usually contagious.

    Signs and symptoms of TB disease

    If your child has TB disease, they may have fever, tiredness, sweating at night time and weight loss. If they have TB disease in the lungs, your child will have 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.

    When to see a doctor

    If you suspect that your child may have TB, or may have been in contact with someone affected by TB, see your GP. The doctor will arrange for some tests to see if your child has been infected with TB.

    • Mantoux test (tuberculin skin test): A skin (scratch) test is done to see whether the child 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 two to three days later to see if there has been a reaction (swelling in the skin).
    • Quantiferon Gold test: This blood test measures how a person's immune system reacts to bacteria that cause TB.

    Both the skin and blood tests can indicate that a child has been infected with TB. However, they do not determine if the child 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 (a coughed-up mixture of saliva and mucus) samples.

    Treatment for TB

    Both TB infection and TB disease are treated with antibiotics. Antibiotics used to treat TB include Isoniazid, Rifampicin, Pyrazinamide and Ethembutol.

    • TB infection: If your child has a TB infection, they must take the antibiotics for at least six months to kill the bacteria and prevent TB disease. Usually only one type of antibiotic is needed.
    • TB disease: 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. TB disease outside of the lungs may need longer courses of antibiotics.

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

    Side effects

    Sometimes the antibiotics used to treat TB can cause side effects. Side effects are less common in children than in adults.

    • Your child may feel sick and lose their appetite.
    • Antibiotics can affect the liver, but this is very rare in children.
    • Rifampicin may turn body fluids (e.g. 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 or pharmacist.

    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.

    Key points to remember

    • TB is extremely rare in Australia.
    • TB infection means your child has the TB bacteria in their bodies, but it is inactive and your child will have no symptoms.
    • In TB disease, the body no longer keeps the TB bacteria under control, and your child becomes unwell.
    • In most cases, TB affects the lungs, but it can also affect the lymph glands, brain, kidneys or spine.
    • TB can be successfully treated by taking a full course of antibiotics. A child with TB disease may need to take antibiotics for six months or longer. 

    For more information  

    Common questions our doctors are asked

    If my child has no symptoms but they have TB infection, how will I know if they are infected? Do they need treatment if they have no symptoms?

    There are straightforward tests (including a chest X-ray and skin test) that will show whether or not your child is infected. You can discuss this with your GP. Even without symptoms, it is important that your child completes their course of treatment.

    Will TB cause permanent damage to my child's lungs?

    TB can affect many different systems within the body. The extent of damage will depend on the severity of disease within any particular system, including the lungs. Talk to your doctor about this.

    Developed by The Royal Children's Hospital Respiratory Medicine department. We acknowledge the input of RCH consumers and carers.

    Reviewed June 2018.

    This information is awaiting routine review. Please always seek the most recent advice from a registered and practising clinician.

    Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit


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