The synovitis of acute gouty arthritis. A light and electron microscopic study

The synovium participates in the inflammatory process of acute gouty arthritis with intense polymorphonuclear leukocyte infiltration, but many chronic inflammatory cells are also seen even during the acute attack. Crystals in the synovial membrane were found in three patients and then only in well defined tophi. Tophus structure was consistent with crystal deposition in a collagen and amorphous matrix with little adjacent inflammatory reaction. Microtophi were superficial and thinly encapsulated, suggesting that crystals from these tophi might easily rupture into the joint space to initiate the inflammatory reaction. Crystals were seen in detached lining cells and other macrophages as well as in polymorphonuclear leukocytes in the synovial fluid. Clinically satisfactory doses of colchicine produced no detectable morphologic changes in microtubules or other structures.