Prospective study of morphology and phagocytosis of synovial fluid monosodium urate crystals in gouty arthritis.

Crystals can be identified in synovial fluids (SF) in the absence of acute inflammation as well as during acute gouty arthritis. We examined gouty joint effusions to evaluate whether observable properties of the crystals correlate with the clinically detectable inflammation. Higher SF leukocyte counts and more crystal phagocytosis were confirmed during more severe arthritis. We found no differences between crystal sizes, numbers of shapes in severe versus mild inflammation. Some patients with severe acute gout had few crystals or only punctate birefringent fragments. Factors other than those we examined must affect the severity of the inflammatory response in gouty arthritis.