What Is It?
Pseudogout is a form of arthritis triggered by deposits of calcium crystals (calcium pyrophosphate dihydrate) in the joints. It is also called calcium pyrophosphate deposition disease (CPPD). This disease can cause short-term or long-term swelling in joints, most often the knee, wrist, shoulder, ankle, or elbow.
As the name suggests, this condition can appear similar to gout, which is caused by another type of crystal – uric acid crystals – and commonly causes sudden pain and swelling in a single joint, usually in the foot. Pseudogout also can resemble osteoarthritis or rheumatoid arthritis.