The X Files – october 2008

A 62-year-old woman presented with bilateral knee crepitus, swelling and stiffness.
Radiographic examination reveals bilateral chondrocalcinosis. (Figures A and B)

Diagnosis: Calcium pyrophosphate dihydrate (CPPD) deposition disease; also known as pseudogout.

Figure A	Figure B

Some points to remember about CPPD:

• inflammatory joint disease resulting from deposition of calcium pyrophosphate dihydrate into the synovial fluid; a metabolic disturbance in which there is an  impaired degradation or excessive production of pyrophosphate
• may be acute (more prevalent in males) or chronic (more prevalent in females)
• frequently associated with diabetes mellitus
• features include articular cartilage calcification, with possible periarticular calcification of synovium, articular capsule, tendons, bursae
• affected hyaline cartilage appears as a fine radiopaque line parallel to the contour of the articular cortex
• affected fibrocartilage demonstrates a characteristic punctate calcification
• in the knee, the menisci classically demonstrate calcification
• joint destruction associated with CPPD is virtually indistinguishable from that of osteoarthritis
• CPPD also tends to affect the shoulder, elbow, radiocarpal joint, hip, symphysis pubis and patellofemoral joint
• joint aspiration may be necessary to confirm the diagnosis •