Relative sensitivity of Tc-99m WBC versus In-111 WBC in a patient with Crohn's disease on steroids.

Numerous studies have shown that chemotaxis is affected by certain antibiotics and steroids. A patient had Crohn's disease in relapse with multiple small bowel fistulae and mesenteric abscesses. Although the Tc-99m WBC scan did not show the intra-abdominal inflammatory foci, an In-111 WBC scan performed within a week delineated the abscesses and these were later confirmed at surgery. This case is being presented not only to show the relative sensitivities of a Tc-99m WBC vs. an In-111 WBC scan, but also to discuss the impediment to polymorphonuclear leukocyte chemotaxis by steroids, which may be a contributory factor to the sensitivities of the different radiopharmaceuticals selected for detection of intra-abdominal septic foci.