A Crystal in Ulcer

Abstract

Purpose: A 61-year-old male presented to the ER complaining of fatigue, dizziness, and BRBPR for two days. Past medical history is significant for GERD, Hep C, GIB secondary to NSAID-induced gastric ulcer, and ESRD s/p two failed renal grafts. Current medications include pantoprazole, sevelamer, kayexalate, senna, and metoprolol. On admission, the patient was found to be hypotensive with a hemoglobin (Hb) of 9 g/dl (baseline 10-11 g/dl). His blood pressure responded appropriately to fluid resuscitation. Subsequent EGD revealed a single non-bleeding gastric ulcer (3 mm) in the pre-pyloric region of the stomach with no stigmata of bleeding. The patient continued to have intermittent episodes of BRBPR, necessitating multiple blood transfusions, and a colonoscopy was done, revealing evidence of colitis and localized ulcerations in the proximal ascending colon and cecum status post biopsies. During the hospitalization, an angiography was also performed, which revealed active bleeding from cecal branches of ileocolic artery status post embolization with cessation of bleeding. Biopsy results from the cecal ulcers on colonoscopy revealed single particle of crystalline material in the background of an ulcer consistent with kayexalate-induced ulcers (Image 1). Many drugs can cause non-specific damage in the large intestine, including solitary hemorrhages, erosions, ulcers, and inflammation. The pathogenesis of the lesions caused by drugs is highly variable, with toxic injury and vascular insufficiency thought to be the most common. Kayexalate-induced intestinal injury reveals rhomboid or triangular basophilic crystals adherent to surface epithelium. Kayexalate is a cation exchange resin which acts in the large intestine by exchanging sodium ions for potassium ions. The mechanism of mucosal damage is not clear, and is reported to be more common in patients with renal failure. It is speculated to be caused by its osmotic action and vasospasm of intestinal vasculature. The patient in this case recovered after discontinuation of kayexalate. This case highlights the importance of medication-induced GI tract injury. Physicians should be aware of colonic ulceration and ischemia in renal failure patients taking kayexalate.Figure: Cecal ulcer biopsy.