Acute calcific periarthritis—a commonly misdiagnosed pathology

Acute calcific periarthritis (ACP) is a self-limiting, monoarticular, peri-articular process of dystrophic mineral deposition and adjacent inflammation. Patients present with a sudden onset of pain, localised swelling, erythema, tenderness and restricted range of motion. Symptoms reduce in severity within 4–7 days and self resolve in 3–4 weeks. ACP is commonly misdiagnosed, in particular, as infective or inflammatory pathologies such as septic arthritis and gout. This condition has specific imaging findings which allows differentiation from other disorders when combined with the clinical presentation. Prompt diagnosis results in appropriate management and reduces the likelihood of unnecessary diagnostic and therapeutic procedures.