Pseudogout is a form of arthritis named for its similarity to gout. Gout is also a form of arthritis, but it typically affects the big toe, while pseudogout attacks larger joints. It most commonly affects the knee, but can also appear in the ankles, shoulders, elbows, or wrists. Episodes of pseudogout can last from a few days to a few weeks and cause sudden, severe pain, warmth, and swelling in the affected joints. Small crystals that form in the joint lining are responsible for the pain and inflammation, though the crystals that cause pseudogout are structurally different from those that cause gout.
There is no known specific cause for why the calcium pyrophosphate dihydrate (CPPD) crystals responsible for pseudogout form, and not everyone who has the crystals present in the joint cartilage will experience symptoms. Pseudogout is more common in elderly people. According to the Mayo Clinic, approximately half of people over the age of 90 have CPPD crystals in their joints. Individuals with chondrocalcinosis, a genetic disorder that causes a predisposition to CPPD crystal formation, can pass the condition on to their children. Joint trauma and excess iron stored in the body are also risk factors for pseudogout.
Physicians can test for pseudogout through joint fluid tests and x-rays. There are many possible causes for joint pain and swelling, so doctors may want to rule out more common forms of arthritis or injury before testing a patient for pseudogout. Joint fluid can be extracted from the affected joint with a thin needle, and can then be microscopically analyzed to look for CPPD crystals. Crystal deposits in the joint lining or cartilage can often be seen on an x-ray. X-rays can also reveal any further joint damage or other conditions caused by crystal deposits.
In addition to episodes of pain and swelling, CPPD crystals can cause other joint damage and problems as well. The bones surrounding the affected joint can develop bone spurs or cysts. Loss of cartilage is also possible, causing the bones to be more susceptible to fracture and other joint injuries.
There is no cure for the CPPD crystals that cause pseudogout, but there are treatment options available to minimize pain and inflammation. Rest and elevation of the affected joints is generally recommended, at least for a few days. Ice and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen can also help ease pain and swelling. Colchicine is a medication used to relieve swelling in gout patients, but it is often used in pseudogout patients who cannot take NSAIDs due to drug interactions or undesirable side effects. As a last resort, a physician may drain the joint of excess fluid with a needle, or inject a corticosteroid into the joint to minimize severe swelling that is resistant to other methods.
Pseudogout symptoms usually subside on their own eventually. It is always advisable to consult a physician during any prolonged period of joint stiffness, pain, or swelling, however. A doctor should be able to rule out any potentially serious conditions.