A form of arthritis with sudden, painful swelling in one or more joints.

Pseudogout (Soo-doe-gout) is a form of arthritis with sudden, painful swelling in one or more joints. The condition is caused by crystals that form in the joint. It's also known as calcium pyrophosphate deposition disease or CPPD.

Pseudogout most commonly affects the knees. Less often, it affects the wrists and ankles. Affected joints can be swollen, warm and extremely painful. Discomfort can last for days or weeks.

Medicines and draining the joint can help relieve pain.