What should you know about septic osteoarthritis?

Osteoarthritis changes the cartilage and tissues around a joint over time. Septic arthritis is different: germs enter the joint and trigger inflammation. When both are present, pain, swelling, heat and stiffness may become more intense or appear more suddenly than a person's usual osteoarthritis symptoms. Reduced movement can develop because the joint is painful and inflamed.

A clinician may examine the joint and take joint fluid for testing. Blood tests or imaging may also help assess the situation. A painful swollen joint should not be assumed to be an osteoarthritis flare, particularly when there is fever, a recent wound or a procedure near the joint.

Treatment commonly requires antibiotics and removal of infected fluid from the joint, using aspiration or a procedure chosen by the treating team. The joint may be rested initially, followed by carefully guided movement as inflammation improves. Medicines for pain or inflammation should be selected with attention to your other conditions and treatments.

Tell the clinician about fever, skin breaks, recent injections, surgery, immune problems and medicines. These details can affect testing and treatment. Do not inject medication into a hot, acutely swollen joint until infection has been assessed.

Seek urgent medical assessment for a suddenly painful, hot or swollen joint, especially if you cannot use the limb normally or feel feverish. Get emergency help for confusion, fainting, severe weakness or rapidly worsening illness. Prompt care matters because infection can damage joint tissues and spread into the bloodstream.

Ask how infection will be confirmed, whether fluid needs to be removed, which antibiotic plan is intended, and when gentle movement can restart. Ask how the infection is being distinguished from your usual osteoarthritis symptoms.