Severe Symptomatic Hypermagnesemia Associated with Over-the-Counter Laxatives in a Patient with Renal Failure and Sigmoid Volvulus

Hypermagnesemia is an uncommon but a potentially serious clinical condition. Over-the-counter magnesium containing products are widely used as antacids or laxatives. Although generally well tolerated in patients with normal renal function, their unsupervised use in the elderly can result in severe symptomatic hypermagnesemia, especially in those patients with concomitant renal failure and bowel disorders. We report a case of severe symptomatic hypermagnesemia associated with over-the-counter laxatives in a 70-year-old male patient with renal failure and sigmoid volvulus, who was successfully treated with hemodialysis. 1. Case History and Hospital Course A 70-year-old male, with past medical history of chronic obstructive pulmonary disease (COPD), long standing hypertension, and congestive heart failure presented with chest tightness and dyspnea, which was progressively getting worse over the past two days. On physical examination, he had labored breathing for which he was subsequently intubated. He also had diffusely tender and distended abdomen. He had trace edema in his lower extremities and absent deep tendon reflexes. Labs were significant for a white cell count of 21300, blood urea nitrogen (BUN) of 44？mg/dL with a creatinine of 2.5？mg/dL, B-type natriuretic peptide (BNP) of 1440, and magnesium of 11？mg/dL. EKG showed a pace maker rhythm. Chest radiograph revealed pulmonary congestion. Abdominal radiograph demonstrated distended loops of bowel with prominent air fluid levels in the left lower quadrant suggestive of sigmoid volvulus. Nephrology service was consulted for acute renal failure and hypermagnesemia. On further questioning, the patient’ family revealed that he was taking about 4 doses of milk of magnesia daily, over the past 5 days for constipation. He was then started on furosemide drip to manage his acute renal failure which seemed most likely due to his poorly controlled congestive heart failure. Subsequently, a flexible sigmoidoscopy was performed which revealed sigmoid volvulus with ulcerated friable area consistent with ischemic injury. Surgical intervention was deferred for management of hypermagnesemia. He was hemodialysed in two sessions of 3 hours each, via a temporary dialysis catheter. Subsequently, his magnesium level and renal function normalized. He was then taken for surgery and intraoperative findings confirmed sigmoid volvulus with ischemic bowel, for which he underwent sigmoid resection and placement of cecostomy. His postoperative course was uneventful. 2. Discussion Magnesium is the second most common intracellular