What is it?
Infection inside a joint can rapidly damage cartilage; absence of fever does not exclude it.
Symptoms and important signs
Severe pain with movement, swelling, warmth or feeling unwell.
How is it assessed?
Urgent examination, blood tests and joint fluid culture as directed by clinicians.
Care and treatment options
Urgent hospital treatment with antibiotics and usually joint drainage.
When to seek help
Seek same-day emergency assessment; do not self-treat with steroid injections.