Pharmacological intestinal obstruction because of calcium polystyrene sulfonate administration.

Cation exchange resins are commonly used as treatment for hyperkalaemia in patients with chronic renal disease. There is a relation between cation exchange resins and the development of gastrointestinal adverse effects. A case of an intestinal obstruction at the terminal ileum is presented that underwent an ileocolic resection because of a critical stenosis of the intestine. The pathologist revealed abundant inflammatory cells together with deposits of calcium polystyrene crystals responsible of the intestinal obstruction. A rare cause of intestinal obstruction to bear in mind in chronically medicated patients with cation exchange resins.