Hemolytic uremic syndrome in small-bowel transplant recipients: the first two case reports

Post-transplant hemolytic uremic syndrome (HUS) is an uncommon but well-described complication in solid organ transplant recipients. Believed to be secondary to immunosuppressive therapy, it has been reported after kidney, liver, pancreas, heart, and lung transplants. In all reported cases, the primary organ affected was the kidney (transplant or native). But until now, no cases after small-bowel transplants and no cases in which the kidney was not the primary organ affected have been reported. We report two cases of HUS in small-bowel transplant recipients. In our first case, clinical presentation was with renal failure; biopsy of the native kidney demonstrated the typical histological changes seen with HUS, namely occlusion of the microcirculation by thrombi and platelet aggregation. Immunosuppression was changed from tacrolimus to cyclosporin, but with no improvement in renal function. In our second case, the transplanted bowel was the primary organ affected. This recipient presented with ulcers in the bowel mucosa, which were believed to be ischemic in origin, secondary to occlusive vascular lesions affecting the small vessels in the transplanted bowel. Her tacrolimus dose was decreased with resolution of ulcers and no evidence of rejection. These two cases represent the first reports of HUS after small-bowel transplants; in addition, our second case represents the first report of an extrarenal graft as the primary organ affected. When caring for small-bowel transplant recipients, physicians must be alert to the possibility of HUS and its various presentations.