Calcium pyrophosphate dihydrate crystal deposition disease

Calcium pyrophosphate dihydrate deposition disease (CPPD) is an arthritis variant. CPPD consists of the deposition of calcium pyrophosphate crystals into soft tissue. It has been found in high concentrations in hyaline cartilage, synovial tissue, capsule, meniscus, labrum, ligamentum flavum and soft tissue of the hand.

CPPD actually is a chemical aberration that manifests as at least 4 separate, yet related, diseases. Chondrocalcinosis has been described as the streaking of the soft tissues with calcium. The term chondrocalcinosis sometimes is misapplied as a synonym for CPPD disease, but technically it refers to the visible presence of calcification within tissues on an imaging study.

Four separate and distinct manifestations of this disease exist, as follows:

[Pseudogout] An acute presentation appears very similar to gout. The knee most often is affected. The shoulder, elbow, ankle, and familiar first metatarsophalangeal (MTP) joint frequently are involved as well.

[Tophaceous pseudogout] The calcium pyrophosphate material can deposit in large accumulations, producing a pseudotumor.

[Familial calcium pyrophosphate dihydrate deposition] A familial pattern which appears at a much earlier age, often as early as the third decade of life. It tends to be more aggressive, with a more ominous long-term prognosis.

[Osteoarthritis] The most common presentation is that of osteoarthritis (OA) alone. Symptoms are identical to those of the typical patient with OA, with the exception that, at some point, the presence of calcium pyrophosphate crystals is appreciated. Most often, this is identified by the presence of chondrocalcinosis. Chondrocalcinosis increases in frequency with age. Injury and surgery may aggravate symptoms.

Estimates vary widely on the frequency of CPPD disease in the USA. It has been described as being present in 4% to more than 25% of the population by age 80 years. Prevalence clearly increases with age. CPPD presents clinically approximately one half as often as gout in the typical practice setting. The male-to-female ratio is approximately 1.4:1.