Psoriatic Arthritis — SCE Rheumatology MCQ

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EasySpondyloarthropathyPsoriatic ArthritisSCE Rheumatology

A 38-year-old woman with longstanding psoriatic arthritis develops progressive shortening and deformity of several fingers. Hand radiographs show extensive osteolysis of the phalanges, producing telescoping digits (an opera-glass hand). Which classical pattern of psoriatic arthritis does this represent?

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Correct answer: E — Arthritis mutilans

The correct answer is E, arthritis mutilans. This is the severely destructive phenotype of psoriatic arthritis, characterised by marked osteolysis and resorption of phalangeal or metacarpal bone. The resulting digital shortening and telescoping produces the characteristic opera-glass hand (doigt en lorgnette). DIP-predominant PsA chiefly identifies the distribution of synovitis and does not itself imply extensive osteolysis. Symmetric polyarthritis can resemble rheumatoid arthritis but lacks the defining telescoping deformity unless mutilans damage has developed. Asymmetric oligoarthritis describes limited peripheral joint involvement, while axial spondylitis predominantly affects the sacroiliac joints and spine. The radiographic osteolysis and telescoping digits therefore uniquely identify arthritis mutilans.

Reference: Haddad A, Johnson SR, Somaily M, et al. Psoriatic Arthritis Mutilans: Clinical and Radiographic Criteria. A Systematic Review. Journal of Rheumatology. 2015;42(8):1432-1438. https://pubmed.ncbi.nlm.nih.gov/26077409/