CPPD DEPOSITION DISEASE: WHAT'S NEW UNDER POLARIZING LIGHT?

Calcium pyrophosphate dihydrate (CPPD) crystals are commonly found in synovial fluids from patients with typical osteoarthritis. These crystals also define unique subsets of patients with inflammatory arthritis. Epidemiology:The general prevalence of calcium crystal arthropathy is not known and is highly dependent on the definition used to collect cases. A new study from Europe demonstrated a prevalence rate of 0.42 % for CPPD deposition disease. This approaches that of gout, which was 0.46 % in this pop-ulation, and supports the concept that CPPD deposition disease is not a rare condition. CPPD deposition disease can be categorized into sporadic, familial and secondary (metabolic) types. The relative proportion of familial to sporadic cases remains unknown. A new familial form of chondro-calcinosis associated with diffuse idiopathic skeletal hyperostosis (DISH) was described in several fami-lies, suggesting the coexistence of factors that promote both these diseases. Metabolic associations of CPPD deposition disease include hyperparathyroidism, hemochromatosis, and hypomagnesemia Clinical Presentation: Clinical CPPD deposition disease typically resembles osteoarthritis, while acute inflammatory arthritis (pseudogout) is also a common presentation. Additional clinical syndromes associ-ated with CPPD crystals mimic other common types of arthritis, such as rheumatoid arthritis. Many cases of CPPD deposition may be asymptomatic