Calcium pyrophosphate dihydrate deposition disease

Definition

Pseudogout is a joint disease that can cause attacks of arthritis. Like gout, the condition involves the formation of crystals in the joints. But in pseudogout, the crystals are formed from a salt instead of uric acid.

Alternative Names

Causes

Pseudogout is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The build up of this salt forms crystals in the joints. This leads to attacks of joint swelling and pain in the knees, wrists, ankles, and other joints.

Among older adults, pseudogout is a common cause of sudden (acute) arthritis in one joint.

Pseudogout mainly affects the elderly. However, it can sometimes affect younger patients who have conditions such as acromegaly, ochronosis, thyroid disease, hemochromatosis, Wilson disease, and parathyroid disease, which are known to increase risk.

Pseudogout can initially be misdiagnosed as gouty arthritis (gout), rheumatoid arthritis, or osteoarthritis

Symptoms

• Attacks of joint pain and fluid accumulation in the joint, leading to joint swelling
• No symptoms between attacks
• Chronic (long-term) arthritis

Exams and Tests

• An examination of joint fluid would show white blood cells and calcium pyrophosphate crystals.
• Joint x-rays may show joint damage, calcification of cartilage, and calcium deposits in joint spaces.

Careful workup, with analysis of crystals found in joints, should ultimately lead to the correct diagnosis. Fortunately, because most conditions involving joint pain are treated by the same medicines (such as steroids and nonsteroidal anti-inflammatory drugs), early misdiagnosis does not necessarily result in inappropriate treatment.

Treatment

Treatment may involve joint aspiration to relieve pressure within the joint caused by fluid buildup. A needle is placed into the joint and fluid is removed (aspirated).

Steroid injections may be helpful to treat severely inflamed joints. A course of oral steroids is sometimes used when multiple joints are inflamed.

Nonsteroidal anti-inflammatory medications (NSAIDS) may help ease painful attacks. Colchicine may be useful in some people.

Outlook (Prognosis)

The probable outcome is good with treatment.

Possible Complications

Permanent joint damage can occur without treatment.

When to Contact a Medical Professional

Call for an appointment with your health care provider if you have attacks of joint swelling and joint pain.

Prevention

There is no known way to prevent this disorder. However, treatment of a known predisposing condition may reduce the severity of pseudogout and may in effect prevent it from developing in unaffected patients.