Fatal Small Bowel and Colonic Ischemia after Sodium Phosphate Bowel Preparation

Abstract

A 69 year old woman with a history of breast cancer, COPD, osteoporosis, and hypertension was scheduled for a colonoscopy for heme positive stools and constipation. Serum creatinine, electrolytes, and hepatic enzymes were normal, and she was instructed to use a sodium phosphate (NaP) bowel preparation. On the day prior to her procedure she ingested 45 ml of an oral NaP solution, and subsequently developed nausea, vomiting and abdominal pain. Upon presentation, she was slightly tachycardic but her blood pressure was normal. Her abdomen was moderately distended with decreased bowel sounds. Serum sodium was 136 mEq/L, potassium 3.6 mEq/L, chloride 96 mEq/L, bicarbonate 16 mEq/L, blood urea nitrogen 12 mg/dL, creatinine 1.3 md/dL, lactate 1.7 mmol/L, phosphate 13.6 mg/dL, and calcium 9.9 md/dL. Computed tomography of the abdomen showed marked feces in the colon with no free air or obstruction. Nasogastric and rectal tubes were placed, and non-phosphate based laxatives administered, without improvement in her abdominal pain. Thirty-six hours later she developed cardiopulmonary distress and was transferred to the intensive care unit. Flexible sigmoidoscopy showed dusky mucosa and she was taken emergently to the operating room. The entire colon and a small portion of the terminal ileum appeared non-viable, and a total colectomy with ileostomy was performed. The following day her lactate had risen to 4.3 mmol/L, the ileostomy appeared necrotic and she was taken back to the operating room for a revision with resection of approximately fifteen centimeters of ischemic ileum. The pathology was consistent with diffuse ischemia and mucosal necrosis. Her hospital course was complicated by nosocomial infection, pneumonia with bilateral effusions, poor wound healing, refractory hypotension, and inability to wean from the ventilator. Her family decided to withdraw support and the patient died. There have been multiple cases of acute phosphate nephropathy resulting from NaP use that led to an FDA warning in 2006. However, in this case despite the hyperphosphatemia the patient never developed significant renal failure. In fact, her phosphorus levels and creatinine normalized and her urine output remained adequate. Fatal small bowel and colonic ischemia related to the use of a NaP bowel preparation has not been reported in the absence of renal failure.