Calcium Pyrophosphate Arthritis (Calcium Pyrophosphate Dihydrate Crystal Deposition Disease; Acute Calcium Pyrophosphate Arthritis; Chondrocalcinosis; Pyrophosphate Arthropathy; Pseudogout) By Sarah F Keller, MD, MA, Cleveland Clinic, Department of Rheumatic and Immunologic Diseases Reviewed / Revised Jul 2022 | Modified Sep 2022 View Patient Education Etiology Symptoms and Signs Diagnosis Prognosis Treatment Key Points Topic Resources Calcium Pyrophosphate Arthritis... Calcium Pyrophosphate Dihydrate... Calcium pyrophosphate arthritis (CPP arthritis) involves intra-articular and / or extra-articular deposition of calcium pyrophosphate dihydrate (CPPD) crystals.