Crystal-Induced Joint Disease

The destructive potential of intracellular crystals has been recognized for over a century. The mechanisms by which crystals induce inflammation and bone and cartilage destruction have been elucidated over the past decade. The three most common crystal-induced arthropathies are caused by precipitation of monosodium urate monohydrate, calcium pyrophosphate dihydrate (CPP) and basic calcium phosphate. The definition, epidemiology, pathogenesis and etiology, diagnosis, and treatment of gout and CPP crystal deposition are reviewed, as well as the clinical stages of gout (i.e., acute gouty arthritis, intercritical gout, advanced gout, nonclassic presentations of gout, and other conditions associated with gout). Also reviewed are the clinical manifestations of calcium pyrophosphate dihydrate deposition disease (CPPD), such as asymptomatic CPPD, osteoarthritis with CPPD, acute CPP crystal arthritis, and chronic CPP crystal inflammatory arthritis. Figures illustrate renal transport of urate, monosodium urate crystals, acute gouty flare, advanced gouty arthritis, gouty synovial fluid, radiographic changes of advanced gout, ultrasound appearance of the femoral intercondylar cartilage, pharmacologic management of gout, the effect of gender and age on knee chondrocalcinosis, radiographs of chondrocalcinosis, and compensated polarized microscopy of CPPD. Tables present the major factors responsible for hyperuricemia, characteristics of classic gouty flares, antiinflammatory therapy for gout, and urate-lowering therapy. This chapter contains 90 references. This review contains 11 figures, 12 tables, and 88 references. Keywords: acute gouty arthritis, intercritical gout, advanced gout, asymptomatic CPPD, osteoarthritis with CPPD, acute CPP crystal arthritis, chronic CPP crystal inflammatory arthritis