Rheumatology and Musculoskeletal Disorders
Rheumatology questions reward pattern recognition across joint distribution, symmetry, and extra-articular features. Candidates must distinguish inflammatory from mechanical joint pain (morning stiffness duration, swelling, systemic features). Know the hallmark features of rheumatoid arthritis, osteoarthritis, gout, and spondyloarthritis, and the autoantibody profiles that support each. Understand the approach to acute monoarthritis, where septic arthritis must be excluded by joint aspiration before assuming gout. Master the systemic nature of lupus and the red flags for vasculitis.
Traps: diagnosing gout without excluding infection in an acute hot joint; relying on uric acid levels during an acute attack (they may be normal); missing extra-articular disease in rheumatoid arthritis; attributing multisystem symptoms to a single organ without considering systemic autoimmune disease.
Worked example: a patient with an acutely swollen, hot knee. The first step is aspiration and fluid analysis, including cell count and culture. Septic arthritis is a medical emergency. Only after infection is excluded should crystal disease be diagnosed and treated.
Rule of thumb: in acute monoarthritis, infection first, crystal second, inflammation third. Never start steroids in a hot joint before aspiration.
Key concepts: inflammatory vs mechanical pain, disease-specific features, autoantibody interpretation, and safe management of the acute joint.