Kids Health Info

Septic arthritis

  • Septic arthritis is a bacterial infection in a joint. Common joints include the knee, elbow and ankle. It may be caused by bacteria entering the joint either through the bloodstream, after a penetrating injury or following an infection of a surrounding bone. Often the cause is unknown. The infection causes the build up of fluid or pus within the joint (effusion).

    Signs and symptoms

    • Symptoms start rapidly.
    • The joint is painful.
    • Decreased movement and use of joint.
    • The joint is hot, swollen and red.
    • Your child may have a fever greater than 38 degrees.
    • They may seem generally unwell.

    Your doctor will make a diagnosis by looking at and assessing the joint, asking questions about recent history such as if your child has had any injury to the area, their symptoms, other infections.  Your child will usually also need an x-ray, bone scan and/or ultrasound and some blood tests.


    • Your child may need to be admitted to hospital for treatment and IV antibiotics.
    • They will need to have an IV drip put in to start antibiotics. 
    • Your child may need a plaster, traction or splint on the joint to stop it from moving.
    • They will get pain relief medicine.
    • They may need to have the infected fluid drained out of the joint.  This is done with a needle or small incision.  This is usually done under a general anaesthetic and may need to be done more than once
    • Your child will need regular blood tests to check their progress and recovery from the infection.  Their temperature will also be checked often.
    • IV antibiotic treatment continues until your child shows signs of improvement - through the blood tests and temperature checks.
    • They may need to keep taking antibiotic liquid or tablets (called oral - by mouth - antibiotics) for another 3-6 weeks, which can continue at home, once their temperature has been normal for 24 hours and  they are taking their oral antibiotics.

    Care at home

    • Making sure your child keeps taking every dose of their oral antibiotics is vital to their recovery from the infection and making sure it does not come back.
    • They must take the entire course of antibiotics.
    • If your child has vomiting or diarrhoea, contact your treating doctor as the antibiotics might not be effective.
    • If your child has some bowel upset *(which may happen from the antibiotics) they can try eating Yakult or yoghurts to sooth the bowel.
    • It is important to keep the follow up appointments - even if your child seems well.
    • Keep an eye out for an increase in temperature or any of the other signs and symptoms listed above.


    Your child will have a follow-up appointment one week after going home.  They will need a blood test, which needs to be taken at least 3 hours before the appointment, so that the results are available for your doctor.  Talk to staff to arrange this before you go home.  If your child starts to get any of the signs and symptoms listed above, please go to the emergency department or contact your treating doctor.

    Key points to remember

    • Each child recovers at a different speed.  It is difficult to know how long they will need to stay in hospital.
    • Regular blood tests are needed to monitor your child's progress, even after going home.
    • It is essential your child takes the entire course of ALL antibiotics for the whole time after going home - this is usually for 3-6 weeks.

    For more information

    • 4 Main - Orthopaedic ward at RCH Tel: (03) 9345-5427
    • Orthopaedic Outpatients RCH Tel: (03) 9345-5311
    • Kids Health Info factsheet: Plaster Care
    • Kids Health Info factsheet: Orthopaedic Wound Care Instructions

    Individual information



    Developed by RCH Orthopaedic Department. First published 2004 Reviewed May 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.