[Gout and and calcium pyrophosphate crystal arthropathies: pathophysiology]

Microcrystalline arthropathies are consecutive to microcrystals formation and deposition within the joint. The formation of monosodium urate crystals depends on many physico-chemical factors: the concentration of uric acid, the temperature and pH. Beyond 60 mg/L (360 µmol/L), uric acid crystallizes in tissues. Chronic hyperuricemia is a necessary condition for the occurrence of gouty arthropathy. The mechanisms of hyperuricemia and inflammatory access and their therapeutic implications are described. Chondrocalcinosis is a radiographic entity characterized by deposits of calcium pyrophosphate crystals (CPP) within the fibrocartilage or hyalin cartilage. CPP arthropathies symptomatology is polymorphic and likely resemble in primary osteoarthritis, pseudo-gout acute attacks, or chronic mono-, oligo- or polyarthritis. Its pathophysiology remains uncompletely understood, although there is growing knowledge on the place of some actors involved in the pathogenesis of chondrocalcinosis, described in the article.