A type of arthritis in which crystals of calcium pyrophosphate or other chemicals are deposited in joints
In pseudogout, crystals of calcium pyrophosphate or similar chemicals are deposited in joints, causing attacks of pain and stiffness. Usually, a single joint is affected. The most common sites are the knee and wrist, but crystals may be deposited in any joint. Although the process of formation and deposition of the crystals may start earlier, symptoms are less common before the age of 60.
In most people, the cause of pseudogout is unknown, although attacks may be triggered by surgery, infection, or injury. Pseudogout is often associated with other joint disorders, particularly osteoarthritis. Pseudogout may also be linked to hyperparathyroidism, a hormonal condition that leads to high blood levels of calcium, or haemochromatosis, a disorder in which the body is overloaded with iron. Pseudogout is more common in women and may run in families.
Symptoms are similar to those of gout. Attacks may cause:
Severe pain, stiffness, swelling, and redness of the affected joint.
Some people have no pain between attacks, while others experience persistent pain and stiffness.
If your doctor suspects pseudogout, he or she may arrange for X-rays of the affected joint. You may also need joint aspiration, in which fluid is removed from a joint for analysis and to relieve swelling.
The symptoms of pseudogout may be relieved by simply removing fluid from the affected joint. In severe cases, a corticosteroid drug may be injected directly into the joint during the same procedure (see Locally acting corticosteroids). You may also need nonsteroidal anti-inflammatory drugs. Once treatment starts, symptoms usually clear up within 48 hours.
There is no cure for pseudogout, but if the underlying cause is treated many people can lead normal lives. Physiotherapy can help to increase joint mobility and muscle strength.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.