Pseudogout is a form of arthritis, or joint inflammation, that is caused by deposits of calcium pyrophosphate crystals in the joints. The crystals cause joint pain and other symptoms. Pseudogout is similar to gout, another form of arthritis in which joint pain is caused by deposits of uric acid crystals.

What is going on in the body?

The joint inflammation of pseudogout is caused by calcium pyrophosphate crystals deposited in the joints. Pseudogout may resemble gout in many ways. The main difference between gout and pseudogout is that the joint crystals are different. In pseudogout, calcium pyrophosphate crystals collect in the joints. In gout, the crystals are uric acid crystals. The crystals in the joint cause similar inflammation and symptoms in both conditions.

What are the causes and risks of the disease?

Pseudogout is caused by the deposit of calcium pyrophosphate crystals in the joints. Why the deposits occur is usually not known. There is some evidence that an enzyme deficiency causes pseudogout, but that cause has not been proven. Occasionally, the cause is hereditary.

Pseudogout is most common in elderly individuals and is more common in males than in females. The risk of pseudogout is increased in individuals who have joint problems from other conditions, such as rheumatoid arthritis. People with hormonal disorders involving the thyroid or parathyroid glands are also more likely to develop pseudogout.