Pseudogout (SOO-doe-gout) is a form of arthritis characterized by sudden, painful swelling in one or more of the joints. Episodes can last for days or weeks.
Pseudogout is formally known as calcium pyrophosphate deposition disease or CPPD. But the condition is commonly called pseudogout because of its similarity to gout. In both pseudogout and gout, crystal deposits form within a joint, although the type of crystal differs for each condition.
It isn't clear why crystals form in joints and cause pseudogout, but the risk increases with age. Treatments can help relieve pain and reduce inflammation.
Pseudogout most commonly affects the knees. Less often, it affects the wrists and ankles. When a pseudogout attack occurs, the affected joints are usually:
- Severely painful
When to see a doctor
Seek medical attention if you have sudden, intense joint pain and swelling.
Pseudogout has been linked to the presence of calcium pyrophosphate dihydrate crystals within the affected joint. These crystals become more numerous as people age, appearing in nearly half the population older than age 85. But most people who have these crystal deposits never develop pseudogout. It's not clear why some people have symptoms and others don't.
Factors that can increase your risk of pseudogout include:
- Older age. The risk of developing pseudogout increases with age.
- Joint trauma. Trauma to a joint, such as a serious injury or surgery, increases the risk of pseudogout in that joint.
- Genetic disorder. In some families, family members have a hereditary tendency to develop pseudogout. These people tend to develop pseudogout at younger ages.
- Mineral imbalances. The risk of pseudogout is higher for people who have excessive calcium or iron in their blood or too little magnesium.
- Other medical conditions. Pseudogout has also been linked to an underactive thyroid gland or an overactive parathyroid gland.
The crystal deposits associated with pseudogout can also cause joint damage, which can mimic the signs and symptoms of osteoarthritis or rheumatoid arthritis.