Sevelamer crystals in the mucosa of the gastrointestinal tract in a teenager with end-stage renal disease

Non-calcium-containing phosphate binders, such as sevelamer preparations, are being increasingly used in patients on dialysis due to their lower association with hypercalcemia and cardiovascular morbidity and mortality. While minor gastrointestinal side effects are quite common with the use of sevelamer, more serious gastrointestinal toxicities have only rarely been reported. We report a pediatric patient on maintenance dialysis receiving sevelamer hydrochloride who developed severe abdominal pain and a high-grade stricture of the sigmoid colon. The patient underwent exploratory laparotomy, resulting in a partial colectomy and colostomy. Histopathologic examination showed colonic mucosal injury and characteristic "fish-scale"-like sevelamer hydrochloride crystals within the mucosa. Whether the sevelamer crystals were causal, contributory or purely incidental remains to be clearly elucidated. However, our case raises sufficient concern to warrant additional investigation into whether there is a causal relationship between sevelamer use and intestinal mucosal injury.