Pseudogout is a form of arthritis that causes pain, stiffness, tenderness, redness, warmth, and swelling in some joints. It can affect one or several joints at once.
What Causes Pseudogout?
Pseudogout results from the abnormal formation of calcium pyrophosphate (CPP) crystals in the cartilage (cushioning material between the bones), which is later followed by the release of crystals into the joint fluid. When CPP crystals are released into the joint, they can cause a sudden attack of arthritis, similar to gout.
The cause of abnormal deposits of CPP crystals in cartilage is unknown. They may form due to abnormal cells in the cartilage, or they may be produced as the result of another disease that damages cartilage. CPP crystals may be released from cartilage during a sudden illness, joint injury, or surgery. The abnormal formation of CPP crystals also may be a hereditary trait.
What Are the Symptoms of Pseudogout?
The symptoms of pseudogout are similar to those of other diseases, especially gout, which is caused by a buildup of uric acid. They also mimic those of rheumatoid arthritis or osteoarthritis. Symptoms include:
- Sudden, intense joint pain
- Swollen joint that's warm to the touch
- Red or purple skin around the joint
- Severe tenderness around the joint (even the slightest touch or pressure may bring extreme pain)
Less often, pseudogout may cause persistent swelling, warmth, and pain in several joints and can even mimic rheumatoid arthritis.
Most symptoms of pseudogout go away within 5 days to a few weeks, even without treatment.
Who Gets Pseudogout?
Pseudogout affects both men and women. Like gout, pseudogout occurs more frequently in people over age 60. People who have a thyroid condition, kidney failure, or disorders that affect calcium, phosphate, or iron metabolism are at increased risk for pseudogout.
Pseudogout also is commonly seen in people who have osteoarthritis. "Attacks" of osteoarthritis associated with pain, swelling, and redness of the joint may in fact be due to pseudogout.
It is unusual for young people to develop pseudogout.
How Frequently Do Pseudogout Attacks Occur?
Like gout, pseudogout attacks can recur from time to time in the same joint or in different joints. The initial attack may last a few days to a few weeks unless it is treated. Unlike with gout, which is linked to excessive alcohol consumption and a diet high in seafood and organ meats, pseudogout attacks are not linked to certain foods in your diet.
Over time, pseudogout attacks may increase, involve more joints, cause more severe symptoms, and last longer. The frequency of attacks is variable. Attacks may occur from once every few weeks to less than once a year. Frequent, repeated attacks can damage the affected joints.
How Is Pseudogout Diagnosed?
Pseudogout cannot be diagnosed simply from a blood test. An X-ray of the joint can be taken to look for the presence of calcium containing crystals located within the cartilage. To diagnose the condition, fluid is removed from the inflamed joint and analyzed under a microscope. The presence of CPP crystals indicates pseudogout.
Fluid is removed through a needle from the inflamed joint in a procedure called "arthrocentesis." Removing the fluid also may help reduce the pressure within the joint and thereby reduce pain.
How Is Pseudogout Treated?
The type of pseudogout treatment prescribed will depend on several factors, including the person's age, other medications they are taking, overall health, medical history, and the severity of the attacks. Drugs to treat pseudogout include:
- Anti-inflammatory painkiller drugs, also called (NSAIDs), generally are prescribed to treat sudden and severe pseudogout attacks. NSAIDs -- such as ibuprofen and naproxen -- usually reduce inflammation and pain within hours.
- Corticosteroids (also called steroids) may be prescribed for people who cannot take NSAIDs. Steroids also work by decreasing inflammation and can be injected into the affected joint or given as pills.
- Colchicine, a gout drug, is sometimes used in low doses for a longer period of time to reduce the risk of recurrent attacks of pseudogout.
Anti-inflammatory medications are usually continued until the pseudogout attack subsides. Symptoms are often relieved within 24 hours after treatment has begun.
If side effects occur, the medication may be changed.