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(Pseudogout)

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease involves intra-articular and/or extra-articular deposition of CPPD crystals. Manifestations are protean and may be minimal or include intermittent attacks of acute arthritis and a degenerative arthropathy that is often severe. Diagnosis requires identification of CPPD crystals in synovial fluid. Treatment is with intra-articular corticosteroids or oral NSAIDs or colchicine.

Etiology

The cause is unknown. Frequent association with other conditions, such as trauma (including surgery), amyloidosis, myxedema, hypomagnesemia, hyperparathyroidism, gout, hemochromatosis, and old age, suggests that Ca pyrophosphate dihydrate (CPPD) crystal deposits are secondary to degenerative or metabolic changes in the affected tissues. Some cases are familial, usually transmitted in an autosomal dominant pattern, with complete penetration by age 40.

Incidence

CPPD crystal deposition (chondrocalcinosis), whether symptomatic and asymptomatic, becomes more common with aging.

The incidence of radiologic (usually asymptomatic) chondrocalcinosis in patients aged 70 is about 3%, reaching nearly 50% in patients aged 90. Asymptomatic chondrocalcinosis is common in the knee, hip, anulus fibrosus, and symphysis pubis. Men and women are affected equally.

Symptoms and Signs

Acute, subacute, or chronic arthritis can occur, usually in the knee or other large peripheral joints, which can mimic many other forms of arthritis. Attacks are sometimes similar to gout but are usually less severe. There may be no symptoms between attacks or continuous low-grade symptoms in multiple joints, similar to RA or osteoarthritis. These patterns tend to persist for life.

Diagnosis

• Synovial fluid analysis
• Identification of crystals microscopically

CPPD crystal deposition disease should be suspected in older patients with arthritis, particularly inflammatory arthritis. Diagnosis is established by identifying rhomboid or rod-shaped, weakly positively birefringent crystals on polarized light microscopy of synovial fluid (see Table 1: Crystal-Induced Arthritides: Microscopic Examination of Crystals in Joints). Coincident infectious arthritis must be ruled out by Gram stain and culture. X‑rays are indicated if synovial fluid cannot be obtained for analysis; findings of multiple linear or punctate calcification in articular cartilage, especially fibrocartilages, support the diagnosis but do not exclude gout or infection.

Prognosis

The prognosis for individual attacks is usually excellent. However, chronic arthritis can occur, and severe destructive arthropathy resembling neuropathic (Charcot's) joints occasionally occurs.

Treatment

• Intra-articular corticosteroids
• NSAIDs
• Colchicine Some Trade Names
  No US trade name
  Click for Drug Monograph
  maintenance

Symptoms of acute synovial effusion abate with synovial fluid drainage and instillation of a microcrystalline corticosteroid ester suspension into the joint space (eg, 40 mg prednisolone Some Trade Names
ORAPRED
PRELONE
Click for Drug Monograph
acetate or prednisolone Some Trade Names
ORAPRED
PRELONE
Click for Drug Monograph
tertiary butylacetate into a knee). Indomethacin Some Trade Names
INDOCIN
Click for Drug Monograph
, naproxen Some Trade Names
ALEVE
NAPROSYN
Click for Drug Monograph
, or another NSAID given at anti-inflammatory doses (see Table 2: Joint Disorders: NSAID Treatment of Rheumatoid Arthritis) often stops acute attacks promptly. Colchicine Some Trade Names
No US trade name
Click for Drug Monograph
0.6 mg po once/day or bid may decrease the number of acute attacks.

Last full review/revision February 2008 by Daniel J. McCarty, MD

Content last modified February 2008