Synopsis
Distinguish an inflammatory musculoskeletal syndrome from mechanical, periarticular, neuropathic and systemic mimics, identify patients who cannot wait, and choose focused tests without treating a laboratory result as the diagnosis.
- Inflammatory pain is suggested by prolonged morning stiffness, rest or night pain, visible synovitis and improvement after movement; mechanical pain more often tracks load and eases with rest, but no single feature is decisive.
- Separate articular pain from tendon, bursa, muscle, bone, nerve and referred pain by locating tenderness and testing active, passive and resisted movement.
- True synovitis combines soft, often warm swelling with restriction or pain through the joint; bony enlargement and crepitus without soft swelling are more consistent with osteoarthritis.
- Ask about psoriasis, uveitis, inflammatory bowel disease, urethritis, preceding infection, Raynaud phenomenon, sicca symptoms, rash, ulcers and family history because these redirect the phenotype.
- Normal CRP or ESR does not exclude inflammatory arthritis, axial spondyloarthritis, infection or vasculitis; abnormal values are nonspecific and must be interpreted with the clinical pattern.
- Do not delay urgent aspiration of a hot swollen joint to await serum urate, autoantibodies or plain radiographs.
- Persistent synovitis of uncertain cause warrants specialist referral even when rheumatoid factor, anti-CCP antibodies or radiographs are normal.
- Use imaging to answer a defined question: radiography for structural damage, ultrasound for accessible synovitis or guided procedures, and MRI for selected occult inflammation or deep anatomy.
Key red flags
Acutely painful restricted joint with fever, immunosuppression, prosthesis or recent procedure is septic arthritis until urgently assessed and sampled; absence of fever is not reassuring.
Night pain unrelated to position, focal bone pain, neurological deficit, vascular change, constitutional symptoms or organ-specific features should expand assessment beyond rheumatology.
Investigation priorities
Establish whether pain arises from joint, periarticular tissue, nerve, spine or referred anatomy.
Management branches
Hot swollen joint, systemic illness, major trauma, severe bone pain or neurological and sphincter symptoms.
- Perform ABCDE where unwell, provide proportionate analgesia, document neurovascular status and seek same-day senior or emergency specialty assessment.
- Obtain urgent cultures, aspiration and imaging according to the threatened structure without delaying antibiotics or surgery in an unstable patient.
- Reassess physiology, pain and function after intervention; record the working differential and the result that will trigger definitive source control or escalation.