Calcium pyrophosphate deposition disease (pseudogout)

Calcium pyrophosphate deposition disease (CPDD), also called pseudogout, is a type of arthritis that occurs when calcium pyrophosphate dihydrate (CPP) crystals build up in the joints. This can lead to pain, stiffness, and swelling in the affected joints. CPDD is often mistaken for gout, another type of arthritis that is caused by the deposition of uric acid crystals in joints.

CPDD most commonly affects middle-aged and older adults. It tends to run in families, so you may be at higher risk if you have a close relative with the condition. There are two types of CPDD. The most common type is primary (idiopathic) CPDD, which occurs when calcium deposits build up in the joints for no known reason. There is also secondary CPDD, which is caused by another preexisting condition that leads to calcium deposit formation, such as joint trauma, osteoarthritis, and hyperparathyroidism.

Symptoms of CPDD may present acutely or develop slowly over time. The most common symptom is pain in the affected joint, ranging from mild to severe. Commonly affected joints include knees and wrists, but they can also affect ankles and hips.