QUIZ: No. 12, 05/04/2026

Diagnosis: Complex Regional Pain Syndrome

Findings: X-ray of the right hand demonstrates patchy periarticular osteopenia involving the carpal bones, head of 2nd to 5th metacarpals and distal radius with subchondral demineralisation. Mildly reduced intercarpal joint space. No erosions or cortical destruction. MRI wrist shows diffuse bone marrow oedema involving multiple carpal bones and distal radius with associated diffuse soft tissue oedema without any focal collection, abscess, or mass lesion. No significant synovial proliferation or erosive changes are noted.

Discussion

Ø  Complex Regional Pain Syndrome (CRPS) is a pain disorder characterised by disproportionate pain with autonomic and trophic changes, usually following trauma or immobilisation.

Ø  Imaging findings evolve with the stage. In the early stages, MRI shows diffuse bone marrow oedema and soft tissue oedema. In later stages, X-ray demonstrates patchy periarticular osteopenia, classically described as Sudeck’s atrophy.

Ø  The hallmark imaging feature is geographic periarticular osteopenia with preserved joint spaces and absence of erosions, helping to differentiate it from inflammatory arthropathies.

Ø  MRI findings are typically diffuse rather than focal, which helps distinguish CRPS from infection or neoplastic processes.

Teaching pearl:

Patchy periarticular osteopenia with diffuse marrow and soft tissue oedema in a painful limb, without erosions, is characteristic of CRPS