Hypermagnesemia Caused by Laxatives in a Patient with Colitis and AKI

Introduction: Hypermagnesemia is uncommon but can be a potentially serious clinical condition with high morbidity and mortality. Magnesium (Mg) containing products are widely used by the general population. Although generally well tolerated in patients with normal renal function, their use in the elderly can result in severe hypermagnesemia particularly with concomitant renal failure and bowel disorders. We report a case of symptomatic hypermagnesemia with laxative use in the setting of acute kidney injury (AKI) and colitis Case Description: 62 y/o male with history of COPD, hypertension, and chronic back pain, on chronic opioid was transferred from community hospital with severe colitis leading to shock. Patient is chronically constipated due to his opioid use.He initially presented with acute abdominal pain and nausea. CT abdomen showed severe colitis with significant stool burden but no obstruction and was given magnesium citrate. Labs revealed Cr of 2.3 mg/dl, WBC 16, Hemoglobin of 15 Mg 8.7 and lactic acid (LA) of 3.1. Patient respiratory status declined and was intubated. At our facility, Mg was 7.9, creatinine 2.9, and BUN of 62. Repeat CT Abd /pelvis shows interval worsening of bowel thickening. He was started on loop diuretics and isotonic fluids for hypermagnesemia, and his Mg level improved gradually. However, the patient’s condition declined over the next few days with worsening shock, AKI and respiratory failure. As per family wishes, the patient was placed on comfort care and no other interventions pursued. Discussion: Magnesium is an important intracellular cation in several enzymatic pathways. Serum magnesium level is affected by magnesium intake, absorption and excretion. In this case, impaired excretion and increased absorption of Mg due to colitis lead to hypermagnesemia and related complications. It is important to monitor for hypermagnesemia with laxative use in a patient with AKI, and colitis. Initial treatment consists of cessation of magnesium-containing medications and therapy with intravenous isotonic fluids plus a loop diuretic. Renal replacement treatment is often required in patients with severe or symptomatic hypermagnesemia in patients with moderate to severe AKI. Early recognition and treatment of hypermagnesemia can be highly effective to prevent significant morbidity and mortality.