MSK & Rheumatology confusion pairs
21 MSK & Rheumatology topics students commonly mix up on Step 1, each with the fastest separator, a side-by-side comparison, and a free practice question.
- Rheumatoid arthritis vs OsteoarthritisRA is inflammatory symmetric MCP/PIP disease with long stiffness; OA is degenerative use-related DIP/PIP or weight-bearing disease with…Video
- Rheumatoid arthritis vs Systemic lupus erythematosusRA is erosive joint-centered synovitis; SLE is multisystem immune-complex disease with nonerosive arthritis and organ involvement.Video
- Systemic lupus erythematosus vs Sjögren syndrome and mixed connective tissue diseaseSLE is immune-complex multisystem nephritis/rash disease; Sjögren is sicca exocrine disease; MCTD is anti-U1 RNP overlap disease.
- Limited systemic sclerosis vs Diffuse systemic sclerosisLimited disease is distal CREST with anticentromere and pulmonary hypertension; diffuse disease is proximal skin and early lung/renal…Video
- Polymyositis vs Dermatomyositis and inclusion body myositisPolymyositis is proximal weakness without rash; dermatomyositis is proximal weakness plus rash and malignancy risk; inclusion body…
- Fibromyalgia vs Chronic fatigue syndrome and myofascial painFibromyalgia is widespread pain amplification; chronic fatigue is post-exertional malaise; myofascial pain is regional trigger-point pain.
- Gout vs Pseudogout (CPPD)Gout is needle-shaped negative birefringence and podagra; pseudogout is rhomboid positive birefringence with chondrocalcinosis, often knee…Video
- Septic arthritis vs Gout and rheumatoid arthritisSeptic arthritis is infected purulent joint until proven otherwise; gout is crystals; RA is chronic symmetric autoimmune synovitis.
- Ankylosing spondylitis vs Reactive, psoriatic, and enteropathic arthritisAS is axial sacroiliitis; reactive follows infection; psoriatic has psoriasis/nails/dactylitis; enteropathic follows IBD activity.
- Polymyalgia rheumatica vs Giant cell arteritis and polymyositisPMR is proximal pain/stiffness with normal CK; GCA is cranial ischemic vasculitis; polymyositis is true weakness with high CK.
- Osteoarthritis hand DIP vs RA MCP/PIP and psoriatic DIPOA DIP has bony nodes and brief stiffness; RA is MCP/PIP inflammatory erosive disease; psoriatic DIP has psoriasis, nail pitting, and…
- Rotator cuff tear vs Adhesive capsulitis and impingementTear is weakness with active motion; adhesive capsulitis loses active and passive ROM; impingement is painful arc with preserved strength.
- Carpal tunnel vs Cubital tunnel and Guyon canal syndromesCarpal tunnel is median nerve at wrist; cubital tunnel is ulnar at elbow; Guyon canal is ulnar at wrist with dorsal ulnar sparing.
- Achilles tendinitis vs Plantar fasciitisAchilles pain is posterior tendon pain with plantarflexion; plantar fasciitis is plantar medial first-step heel pain.
- Osteomalacia vs Osteoporosis and Paget diseaseOsteomalacia is undermineralized painful bone; osteoporosis is low mass with normal labs; Paget is high-turnover enlarged disorganized bone.
- Osteosarcoma vs Ewing sarcoma, chondrosarcoma, and osteoid osteomaOsteosarcoma is metaphyseal osteoid sunburst; Ewing is diaphyseal onion-skin t(11;22); chondrosarcoma is older cartilage pelvis; osteoid…
- Multiple myeloma vs Plasmacytoma and bone metastasisMyeloma is systemic plasma-cell CRAB disease; plasmacytoma is solitary plasma-cell mass; metastasis is bone involvement from another…
- Compartment syndrome vs DVT and cellulitisCompartment syndrome is ischemic pressure pain with passive stretch; DVT is venous swelling; cellulitis is infectious red warm skin.
- Lateral epicondylitis vs Medial epicondylitisLateral epicondylitis is extensor pain with resisted wrist extension; medial epicondylitis is flexor-pronator pain with resisted wrist…
- ACL injury vs PCL, MCL, and LCL injuriesACL is anterior translation after pivot; PCL is posterior drawer after dashboard; MCL is valgus; LCL is varus.
- Meniscal tear vs Ligament tearMeniscus is mechanical locking/clicking with joint-line tenderness; ligament tear is instability and abnormal stress test laxity.