Pseudogout

Definition

Pseudogout is a form of arthritis that causes pain, redness, and inflammation in one or more joints.

Description

Pseudogout is also known by another name: calcium pyrophosphate dihydrate deposition disease (CPPD), the basis of which is derived from the calcium deposits that collect in the joint. The deposits or crystals, as they are sometimes called, cause pain and inflammation in the joint. According to the Arthritis Foundation, this can eventually weaken the cartilage, which serves as padding between the bones, "allowing bone to rub against bone." Pseudogout typically affects the large joints, such as the knees, wrists, and ankles. In general, it occurs with equal frequency in men and women.

Most often seen in older adults, pseudogout can also affect younger patients, especially those with diseases that put them at a greater risk of developing it, such as hemochromatosis, hypercalcemia, hypothyroidism, ochronosis, or Wilson's disease. Some people, according to an article for the American College of Rheumatology, experience attacks of pseudogout "following joint surgery or other surgery. Because many older people have calcium crystal deposits in their joints, any kind of insult to the joint can trigger the release of the calcium crystals, which then induce a painful inflammatory response." Pseudogout affects about 3% of elderly people. Not all will experience severe attacks. By their nineties, 50% of people will have joint deposits. Although researchers have noticed that some people with pseudogout also have a family history of the disease, it is not clear what role genetics might play in its development.

Causes and symptoms

As the Arthritis Foundation points out, it is unclear what causes the crystals to form, but some speculation exists that "an abnormality in the cartilage cells or connective tissue could be responsible" for their development. Acute pain and fluid accumulation that leads to joint swelling are typical symptoms of pseudogout. When the crystals move into a joint, the Arthritis Foundation categorizes the pain as "sudden and severe." Many patients report that joint motion is limited. Statistically speaking, in 50% of the cases, the patient will run a fever. Half of all the acute pseudogout attacks will involve a knee. The experts at MedlinePlus identify "chronic (long term) arthritis" as a symptom that can be present at the time of an acute pseudogout attack. The word "acute" implies short term; therefore, acute attacks of pseudogout will come and go, but chronic arthritis may remain. In addition, progressive degenerative arthritis is sometimes seen in numerous joints.

Diagnosis

Pseudogout and gout have similar symptoms, which can be confusing. However, uric acid is associated with gout, whereas calcium pyrophosphate crystals are associated with pseudogout. After a patient's detailed medical history is obtained, a diagnosis can be made based on the symptoms and medical tests.

Using a needle, the physician can take a sample of the synovial fluid from the swollen or painful joint to ascertain the presence of calcium pyrophosphate crystals. The fluid will also contain white blood cells, which can be counted to assist in the diagnosis. Synovial fluid is the lubricating fluid that's secreted by the membranes that line the joints.

X rays may also be taken to confirm the presence of crystals. The x-rays may also show joint damage or that crystals have led to a condition called chondrocalcinosis, which is calcification of the cartilage. Other possible causes such as gout, rheumatoid arthritis, or infection must be ruled out too. Blood tests can also help to confirm the diagnosis. Indeed, as the experts at MedlinePlus indicated, "careful workup, with analysis of crystals found in the joints, should ultimately lead to the correct diagnosis."

Treatment

There are a variety of treatment options. It if the patients have an adequate support system, such as family and friends willing to help, it makes it easier for patients to recover faster. Patients are often advised to avoid putting pressure on the affected joint. In some cases, it is appropriate for the patient to engage in special isometric exercises designed to help their specific condition heal faster. Once the inflammation and pain subsides, exercises are sometimes suggested to regain range of motion.

Medications can be prescribed to ease the pain, which typically fall into the nonsteroidal anti-inflammatory category. For example, ibuprofen (Motrin) and naproxen (Aleve) are nonsteroidal anti-inflammatory drugs (NSAIDs) that are used quite often, because they are generally well tolerated and highly effective. However, in the article Dr. Schumacher wrote for the American College of Rheumatology he cautions patients by stating that, "people with poor kidney function, a history of stomach ulcers, and those who are on blood thinners often cannot take NSAIDs." Indomethacin (Indocin) is also a first-line drug that is commonly used to treat pseudogout that falls into this category.

When no infection is present, steroids, such as prednisone, may be prescribed. Much of the literature discussing treatment options also suggests a medication called colchicine, which is only available as a generic. It is generally prescribed in low doses and should not be used by anyone with significant bone marrow dysfunction or renal insufficiency. Patients should talk with their physicians regarding any other reasons why colchicine may not be suitable for them.

In order to relieve some of the pressure, the excess fluid around the joint can be removed (or aspirated, as it is sometimes called) with a needle.

Treatment options to reduce inflammation are valuable, "because they may slow the progression of joint degeneration that often accompanies pseudogout," according to Dr. Schumacher in his American College of Rheumatology article. If joint degeneration does occur, surgery is available to replace or repair damaged joints; however, it is better for patients to engage in preventative measures that will help them avoid the need for surgery. As the old saying goes, "an ounce of prevention is worth a pound of cure."

Prognosis

With regard to an acute attack of pseudogout, the prognosis is usually very good. The symptoms usually go away within two weeks. However, over time, joint degeneration can occur.

Prevention

There are not specific techniques applicable to every patient to prevent the formulation of the crystals; however, some patients with certain diseases are at greater risk of developing them. Diagnoses and treatment of underlying disorders is one of the most important aspects of managing crystal-induced arthopathies. Once a causative crystal is identified and a diagnosis has been established, long-term management and prevention can be devised.

KEY TERMS

hemochromatosis— This disease refers to when a person's body absorbs too much iron.

hypercalcemia— This disease refers to when a person's bones absorb too much calcium.

hypothyroidism— This disease refers to when a person's thyroid gland is underactive.

ochronosis— People with this rare hereditary condition tend to develop arthritis in adulthood.

Wilson's disease— Wilson's disease causes the body to retain copper, which ultimately can lead to liver damage.

Resources

PERIODICALS

Schumacher, H. R. "Crystal-induced arthritis: an overview." American Journal of Medicine 100 (1996): 46S-52S.

OTHER

Arthritis Foundation "Calcuim pyrophosphate dehydrate crystal deposition disease (CPPD) pseudogout." Arthritis Foundation 2004. The Arthritis Foundation. 29 Mar. 2005 〈http://www.arthritis.org/DiseaseCenter/cppd.asp〉.

Medline Plus "Pseudogout." U.S. National Library of Medicine July 2004. U.S. National Library of Medicine and the National Institutes of Health. 29 Mar. 2005 〈http://www.nlm.nih.gov/medlineplus/ency/article000421.htm〉.

Schumacher, H. R. "Pseudogout." American College of Rheumatology April 2004. American College of Rheumatology. 29 Mar. 2005 〈http://www.rheumatology.org/public/factsheets/pseudogout_new.asp〉.