Relative sensitivity of Tc-99m WBC versus In-111 WBC in a patient with Crohn disease and steroid use.

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