Musculoskeletal and Rheumatological Conditions
What this domain tests
Separating mechanical from inflammatory disease, recognising the rheumatological emergencies, and avoiding unnecessary imaging.
Core rules
- Low back pain. Most is non-specific. Imaging is indicated only for red flags: age over 50 with new pain, night pain, weight loss, fever, intravenous drug use, trauma, progressive neurology, bladder or bowel dysfunction or saddle anaesthesia (cauda equina - emergency).
- Polymyalgia rheumatica. Age over 50, bilateral shoulder and hip girdle pain with morning stiffness over 45 minutes and a raised ESR/CRP; a dramatic response to low-dose prednisolone supports the diagnosis.
- Giant cell arteritis is a same-day emergency. New headache, scalp tenderness, jaw claudication, visual loss or diplopia - start high-dose steroids immediately, arrange ESR/CRP and urgent specialist or ophthalmology assessment. Do not wait for bloods.
- Rheumatoid arthritis. Persistent, symmetrical small-joint synovitis with early-morning stiffness needs anti-CCP, rheumatoid factor and urgent referral, ideally within six weeks, because early disease-modifying therapy prevents erosion.
- Septic arthritis. An acutely hot, swollen joint with fever needs same-day aspiration - do not treat with oral antibiotics and review.
- Gout is diagnosed clinically in a classic podagra; joint aspiration is definitive when septic arthritis is possible.
Worked example
A 69-year-old reports six weeks of pain in both shoulders and hips, unable to turn in bed, with a CRP of 48. The pattern and raised inflammatory markers suggest polymyalgia rheumatica. You start prednisolone 15 mg daily, arrange review in a week to confirm the response, and counsel about bone protection and relapse. The reasoning: bilateral girdle pain with inflammation is a diagnosis, not a strain.
Traps
- Ordering lumbar imaging for mechanical back pain.
- Waiting for ESR before starting steroids in suspected giant cell arteritis.
- Treating an acute hot joint as gout without excluding sepsis.
- Missing cauda equina because the patient is "walking and talking".