Curriculum · Musculoskeletal / Orthopedic / Rheumatology
Pseudogout (calcium pyrophosphate deposition)
What it is
Pseudogout is a crystal arthropathy caused by calcium pyrophosphate crystals, which are deposited in the joint and cause joint problems; it is also known as chondrocalcinosis. The newer name is acute calcium pyrophosphate crystal arthritis, and the term pseudogout refers to the acute form of CPPD disease, not the chronic one.
Causes and risk
It affects mainly people over 50 and the majority are elderly, with men and women affected about the same. The risk factors listed are a history of joint trauma, familial chondrocalcinosis and hyperparathyroidism. An attack can arise on its own or be triggered by joint trauma or surgery or by an acute illness.
How it presents
The attack is one of acute pain and swelling in the affected joint. It is a monoarthritis, occasionally oligoarticular, and the typical picture is an older adult with a hot, swollen, stiff and painful knee. The knee is the most common site, then the wrist, and other large joints such as the shoulders, the hips and the ankles may be involved, along with the hand at the MCP joints and the foot at the first MTP joint. The attack is typically self-limited, but differs from acute gout by its longer duration and by possible systemic symptoms. It can also be a chronic condition affecting multiple joints, or be asymptomatic and picked up incidentally on an x-ray of the joint; a chronic inflammatory arthritis in pseudogout is rare and then resembles rheumatoid arthritis.