Upper gastrointestinal tract injury in patients receiving kayexalate (sodium polystyrene sulfonate) in sorbitol - Clinical, endoscopic, and histopathologic findings

Kayexalate (sodium polystyrene sulfonate) in sorbitol has been demonstrated to cause colonic necrosis in a subset of uremic patients who are administe red the cation exchange resin for treatment of hyperkalemia. Upper gastroin testinal damage associated with Kayexalate in sorbitol is reported far less frequently, and the clinicopathologic spectrum of disease in cases with up per gastrointestinal damage has not been investigated previously. The autho rs studied the clinical, endoscopic, and histologic features of 11 patients with Kayexalate crystals in biopsies from the esophagus (n = 7), stomach ( n = 6), and duodenum(n = 2). The endoscopic appearance was markedly abnorma l in all 11 patients. The effects of the medication closely mimicked other endoscopic and radiologic diagnoses in three cases, including esophageal ca rcinoma, Candidal esophagitis. and gastric bezoar. Histologic and/or endosc opic evidence of mucosal injury in the form of an ulcer or erosion was pres ent in nine patients (82%). In four patients with mucosal injury, no other etiology apart from Kayexalate in sorbitol could be identified. In comparis on with a cohort of patients with Kayexalate crystals in lower gastrointest inal specimens identified during the same period (11 patients) the frequenc y of associated mucosal damage was not significantly different (55%, p = 0. 19), but no patient with upper gastrointestinal Kayexalate required surgica l resection or died as a result of Kayexalate-induced mucosal injury. The r esults of this study provide evidence that Kayexalate in sorbitol can induc e damage to the upper gastrointestinal tract. Recognition of Kayexalate cry stals in histologic sections as a marker for sorbitol-induced mucosal damag e may aid in establishing the correct diagnosis for clinically or endoscopi cally misleading lesions.