Synovial effusions containing cholesterol crystals report of 12 patients and review.

Cholesterol crystals were identified in 16 synovial fluids from 12 patients who were seen over the 14-year period 1964 through 1977. Ten of the 12 patients had rheumatoid arthritis of a median duration of 12 years. One patient had ankylosing spondylitis and another had iliopectineal bursitis without other joint disease. The fluids were usually turbid, white, or yellow in color and of thick consistency. When the synovial fluid concentration of cholesterol was determined, it was higher than the serum level. The swollen joints and bursae did not respond favorably to simple aspiration or corticosteroid injections but did to surgical synovectomy. No relationship was found between synovial fluid accumulation of cholesterol crystal and previous intra-articular corticosteroid therapy, serum lipoprotein abnormalities, intra-articular hemorrhage, or generalized arteriosclerosis. The results suggest that local factors are most important in the development of synovial fluid cholesterol crystals, but the exact mechanisms are unknown. The presence of cholesterol crystals in synovial fluid should suggest a severe persistent synovitis, knowledge of which may be helpful in diagnosis and planning therapy.