Six weeks after a minimally displaced Colles' fracture treated in a cast, a 55-year-old woman reports burning pain, swelling, shiny discoloured skin, and stiffness disproportionate to her injury. Radiographs show patchy spotty demineralisation of the carpus. The MOST likely diagnosis is:

• A Carpal tunnel syndrome
• B Post-traumatic osteomyelitis
• C Delayed union of the radius fracture
• D Reflex sympathetic dystrophy (complex regional pain syndrome type I) ✓

Explanation

Complex regional pain syndrome type I, historically called Sudeck's atrophy, follows minor trauma or immobilisation and features pain out of proportion, vasomotor and trophic skin changes, swelling, stiffness, and patchy spotty osteoporosis on radiographs. Triple-phase bone scan showing diffuse increased uptake supports the diagnosis. Osteomyelitis would show fever and focal bony destruction, while carpal tunnel syndrome causes median nerve symptoms without trophic changes or demineralisation.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.