Pseudogout

Pseudogout

Author
Michael A Becker, MD
Section Editor
H Ralph Schumacher, MD
Deputy Editor
Paul L Romain, MD

Disclosures

PSEUDOGOUT DEFINITION — Pseudogout is a form of arthritis that causes sudden attacks of joint pain and swelling. The prefix “pseudo” means appearing like something else; the term “pseudogout” is commonly used because the symptoms of the disorder are very similar to those caused by gout. Gout is an arthritis caused by urate (sometimes referred to as uric acid) crystals. (See “Patient information: Gout”.)

Although the two disorders can cause similar symptoms, patients with pseudogout are treated somewhat differently than patients with gout (see ‘Pseudogout treatment’ below).

PSEUDOGOUT SYMPTOMS — Pseudogout can cause sudden attacks of joint pain, swelling, and warmth. An attack can last for days or even weeks. The knee is affected in over 50 percent of patients with pseudogout; however, the disorder can also affect the ankles, feet, shoulders, elbows, wrists, or hands. (See “Clinical manifestations and diagnosis of calcium pyrophosphate crystal deposition disease”.)

PSEUDOGOUT CAUSES AND RISK FACTORS — Pseudogout develops in some people in response to the presence of calcium pyrophosphate dihydrate (CPPD) crystals in the joints. The crystals first develop in the joint cartilage and eventually move to the lining of the joint (also called the synovium) or into the joint fluid where they cause inflammation; this causes pain and swelling. It is not known exactly why CPPD crystals form in the joints. (See “Pathogenesis and etiology of calcium pyrophosphate crystal deposition disease”.)

Some people, particularly older adults, have CPPD crystals in their joints (chondrocalcinosis) but never experience symptoms of pseudogout. Up to 50 percent of people age 90 have chondrocalcinosis.

In addition to older age, there are several other factors that increase the risk of accumulating CPPD crystals in the joints, including:

Joint trauma — People who have previously experienced a significant injury to or surgery on a joint have an increased risk of developing CPPD crystal deposits.

Genetics — People can inherit a predisposition to CPPD crystal deposition (called “familial chondrocalcinosis”); these people are more likely to develop pseudogout or other features of calcium pyrophosphate crystal deposition disease earlier in life.

Excess iron — People with a genetic disorder called hemochromatosis, which causes the body to store excess iron, are at an increased risk of developing CPPD crystal deposits. (See “Patient information: Hemochromatosis (hereditary iron overload)”.)

Other related disorders — Several metabolic and endocrine disorders are associated with calcium pyrophosphate crystal deposition disease. These include hyperparathyroidism (overactive parathyroid glands), hypophosphatasia (an inherited metabolic bone disorder), hypomagnesemia (low levels of magnesium in the blood), Gitelman’s syndrome (an inherited kidney disorder), and possibly others.

PSEUDOGOUT DIAGNOSIS — A healthcare provider can confirm or rule out a diagnosis of pseudogout by performing an examination and tests. In many patients, a sample of joint fluid is obtained in order to determine whether CPPD crystals are present and to exclude arthritis due to other causes, such as gout or joint infection.

Synovial fluid analysis — Synovial (joint) fluid is obtained through a needle inserted into the affected joint. The fluid is then analyzed to determine if CPPD crystals or infection are present. The presence of CPPD crystals in a patient with joint pain and inflammation suggests pseudogout, whereas urate crystals suggest gout.

Imaging (X-rays) — A healthcare provider may examine the painful joint(s) by taking X-rays. This can reveal calcium-containing crystal deposits in the cartilage, a condition known as chondrocalcinosis.

PSEUDOGOUT COMPLICATIONS — CPPD crystal deposition disease can lead to rapidly progressing osteoarthritis, caused by wearing down of the joint cartilage, bone cysts or spurs, and even fractures. These changes may occur in joints not usually involved in osteoarthritis, such as the knuckles and wrists.

Although treatment of pseudogout episodes can shorten the duration of the attack, treatment may not decrease the risk of developing chronic arthritis. Treatment of this type of damage is similar to the treatments used for osteoarthritis. (See “Patient information: Osteoarthritis treatment”.)

PSEUDOGOUT TREATMENT — There is no treatment that can completely remove or prevent the formation of calcium pyrophosphate dihydrate (CPPD) crystals. However, the joint pain and swelling generally resolve with treatment, including the following:

Joint aspiration and/or injection — A clinician may insert a needle into the affected joint to remove the fluid and crystals that have accumulated. This can help to relieve pressure and pain. An injection of glucocorticoids (steroids) into the joint may relieve the associated joint inflammation.

Oral medications — Joint aspiration or injection is usually preferred when one or two joints are affected, but may not be recommended if more than two joints are affected. In this case, an oral medication (NSAIDS, oral glucocorticoids, colchicine) may be preferred.

Taking an NSAID such as ibuprofen (Advil®, Motrin®), indomethacin (Indocin®), or naproxen (Aleve®, Naprosyn®) can help to relieve symptoms of pain and inflammation. Prescription-strength tablets may make it more convenient to take the relatively high doses of NSAIDs that are needed to control an attack. (See “Patient information: Nonsteroidal antiinflammatory drugs (NSAIDs)”.)

Joint immobilization — Patients may be advised to avoid weight bearing (walking or running if the legs or feet are involved), avoid excessive movement, and limit activity for a period of time to minimize pain and swelling. In some cases, a temporary splint will be recommended to limit joint movement.

Treatment of related conditions — If the CPPD crystal deposits are caused by a separate disorder (see ‘Other related disorders’ above), that condition may require treatment. (See “Treatment of calcium pyrophosphate crystal deposition disease”.)

PSEUDOGOUT PREVENTION — For patients who experience frequent episodes of pseudogout, a healthcare provider may prescribe daily colchicine. Use of this medication, which is also often used to treat or prevent gout, can reduce the number of pseudogout attacks. The benefits and risks of preventive therapy should be discussed with a healthcare provider. (See “Patient information: Gout”.)

SUMMARY

Pseudogout is a form of arthritis that develops in people with calcium pyrophosphate crystal deposition disease. It is caused by the buildup of calcium pyrophosphate dihydrate (CPPD) crystals within a joint.
The symptoms of a pseudogout attack include joint pain, swelling, and warmth. (See ‘Pseudogout symptoms’ above.)
The treatment of pseudogout is aimed at the relief of symptoms. This may include non-steroidal anti-inflammatory drugs (NSAIDs) to treat inflammation, the removal of fluid and/or injection of steroids in the joint to alleviate pressure and reduce inflammation, and/or immobilization (rest) of the affected joint. If the pseudogout is caused by a separate disorder, treating that condition may be necessary to prevent complications of the related disease; this may not affect the course of pseudogout (see ‘Pseudogout treatment’ above).
Some patients who suffer from frequent attacks of pseudogout may be given a medication called colchicine to help prevent future episodes. (See ‘Pseudogout prevention’ above.)
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient Level Information:

Patient information: Gout
Patient information: Hemochromatosis (hereditary iron overload)
Patient information: Osteoarthritis treatment
Patient information: Nonsteroidal antiinflammatory drugs (NSAIDs)

Professional Level Information:

Clinical manifestations and diagnosis of calcium pyrophosphate crystal deposition disease
Pathogenesis and etiology of calcium pyrophosphate crystal deposition disease
Treatment of calcium pyrophosphate crystal deposition disease

The following organizations also provide reliable health information.

National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)

National Institute of Arthritis and Musculoskeletal and Skin Diseases
(301) 496-8188
(www.nih.gov/niams/)

American College of Rheumatology/Association of Rheumatology Health Professionals
(404) 633-3777
(www.rheumatology.org)

The Arthritis Foundation
(800) 283-7800
(www.arthritis.org)

 

REFERENCES
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Bong D, Bennett R. Pseudogout mimicking systemic disease. JAMA 1981; 246:1438.
Jones AC, Chuck AJ, Arie EA, et al. Diseases associated with calcium pyrophosphate deposition disease. Semin Arthritis Rheum 1992; 22:188.
O’Duffy JD. Clinical studies of acute pseudogout attacks: comments on prevalence, predispositions, and treatment. Arthritis Rheum 1976; 19 Suppl 3:349.
Fam AG, Topp JR, Stein HB, Little AH. Clinical and roentgenographic aspects of pseudogout: a study of 50 cases and a review. Can Med Assoc J 1981; 124:545.
Alvarellos A, Spilberg I. Colchicine prophylaxis in pseudogout. J Rheumatol 1986; 13:804.