Reaction of superficial bursae in response to specific disease stimuli.

Although microscopic studies have shown similarities between bursal and joint membranes, little is known about bursae and their response to disease states. Eighty-six cases of superficial bursitis due to trauma, bacterial infection, or gout were reviewed and compared with cases of joint inflammation due to the same etiologies. In traumatic bursitis the bursal fluid mucin test was more abnormal and the viscosity lower than that of joint fluid in traumatic arthritis. The bursal fluid total leukocyte count of septic bursitis was less than 20,000/mm3 in 8 of 13 cases but in only 1 of 21 synovial fluids from cases of septic arthritis (P = 0.005). In gouty bursitis the mean total leukocyte count of bursal fluid was 2800/mm3, compared with a mean synovial fluid total leukocyte count of 28,700 in gouty arthritis (P less than 0.02). These findings indicate that superficial bursae react less intensely than diarthrodial joints to specific disease stimuli and that a relatively low bursal fluid leukocyte count is often present in cases of septic and gouty bursitis.