A case report of sevelamer-associated recto-sigmoid ulcers

Abstract

Background: Optimal phosphorous control is an important aspect of the care of patients with end-stage renal disease, and phosphate binders are usually needed.

Case presentation: A 74-year-old woman with end-stage renal disease on maintenance hemodialysis presented to the emergency room with abdominal discomfort, rectal pain, and blood-tinged stools. Initial concern was for a rectal carcinoma, based on the symptoms and imaging in initial computerized tomography of the abdomen showing rectal wall thickening, and her clinical presentation. She had been treated with the phosphate binder sevelamer for two months. In this case report, we explore the unique features of sevelamer-associated recto-sigmoid ulcers which led to her symptoms.

Conclusion: Sevelamer is widely used in chronic kidney disease and end-stage renal disease patients with hyperphosphatemia. It is a crosslinked polymeric amine that binds phosphates and bile acids; it is not systemically absorbed. To the authors' knowledge, this is the first reported case of recto-sigmoid ulcers associated with use of this phosphate binder. Nephrologists, pathologists, and gastroenterology sub-specialists should be aware of this recently-reported entity in patients on sevelamer with suggestive symptoms, as this medication is widely used in renal patients.

Fig 1

a and b Rectal mucosa with ulcerations, exudates, and purplish hue. c CT scan showing circumferential rectal wall thickening (arrow) with adjacent fat stranding and apparent adhesion to the mesorectal fascia

Fig 2

Characteristic histologic appearance of sevelamer pill fragments, featuring crystalloid structures with broad, slightly-curved, irregular “fish scales” with a two-toned (pink and tan-yellow) color seen on mucosal biopsy. (Hematoxylin and eosin stain, 400x magnification)