What is pseudogout?

DEAR DOCTOR K:

What is pseudogout? Is it related to gout?

DEAR READER:

Pseudogout is a form of arthritis triggered by deposits of calcium crystals in the joints. As crystals accumulate in the affected joint, they can cause a reaction that leads to severe pain, redness, warmth and swelling. The attack often lasts several days, and can last weeks.

As the name suggests, pseudogout can cause symptoms similar to those of gout. Gout is caused when another type of crystal, uric acid, accumulates in a joint. Gout commonly affects just a single joint — most often the big toe. Pseudogout also can resemble osteoarthritis or rheumatoid arthritis, in making multiple joints ache simultaneously. It most often occurs in the knee, wrist, shoulder, ankle or elbow.

Pseudogout is most common in older people and tends to run in families. For reasons we don’t fully understand, people who suffer from any of the following conditions are more likely to develop pseudogout:

  • age-related degenerative joint disease, also called osteoarthritis;
  • past joint injury;
  • underactive thyroid (hypothyroidism);
  • a condition called hyperparathyroidism;
  • an inherited condition that leads the body to absorb too much iron, called hemochromatosis.

Frequently, however, doctors cannot identify anything that might have triggered the disease.

To diagnose pseudogout, your doctor may remove a sample of fluid from an inflamed joint. He or she will test it for the presence of calcium crystals and for uric acid crystals (to determine if it is gout). The fluid also will be tested for an infection or other cause of joint inflammation. Your doctor may test for conditions that can trigger pseudogout, too.

Removing the fluid from an inflamed joint to make a diagnosis, a procedure called joint aspiration, can also help to relieve the symptoms. It eases the pressure and discomfort. After the area is numbed, the doctor inserts a needle to withdraw fluid.

Treatment usually includes pain- and inflammation-relieving NSAIDs or injections of a glucocorticoid to keep the swelling down. These two treatments usually eliminate symptoms within hours to a few days. If the doctor determines that you cannot take these medicines, you may instead be prescribed corticosteroid pills for a short time.

Preventing future attacks is possible. If another condition is triggering attacks of pseudogout, such as an underactive thyroid, treatment of that condition may prevent future attacks. In addition, your doctor may prescribe a medicine called colchicine (Colcrys) or an NSAID to take regularly. Both types of treatment help to prevent the inflammation in the joint.

While there is a medicine that lowers the level of uric acid in the body, and thereby reduces the attack rate of gout, there is no comparable medicine yet to prevent attacks of pseudogout.

Over time, pseudogout can cause a joint to degenerate in people with recurrent or ongoing symptoms. In this case, surgery (such as joint replacement) may become the only effective treatment.

Pseudogout is a chronic, annoying problem that usually responds to prompt treatment. Fortunately, serious consequences are rare.