THE MONSTROSITY OF MAGNESIUM CITRATE

ABSTRACT

SESSION TITLE Critical Gastrointestinal Case Reports SESSION TYPE Rapid Fire Case Reports PRESENTED ON 10/18/2022 1225 pm - 0125 pm INTRODUCTION: Magnesium citrate is an osmotic laxative which is occasionally used in the intensive care unit (ICU) for refractory constipation. We present a patient in whom a bowel regimen containing magnesium citrate resulted in severe hypermagnesemia with paralytic ileus, requiring renal replacement therapy. CASE PRESENTATION 70-year-old male was admitted to the ICU for COVID-19 associated acute hypoxic respiratory failure and suffered multi-day, refractory constipation, treated with one dose of 17 grams of magnesium citrate. Vital signs were remarkable for bradycardia and hypotension. On examination, patient was lethargic and the abdomen was soft and non-distended, but there were decreased bowel sounds throughout. Subsequently, laboratory findings were notable for a magnesium level of 8.8 mg/dL and serum creatinine of 2.3 mg/dL (estimated glomerular filtration rate 28mL/min/1.73m2), all of which were previously normal at admission. Computerized Tomography of the abdomen was performed showing dilated cecum, ascending and transverse colon and moderate to large amount of intraluminal rectal stool and air. Patient was started on intravenous fluids, loop diuretics, and calcium gluconate, however, the patient required renal replacement therapy for magnesium clearance. Patient clinically improved with normalization of kidney function and magnesium levels as well as resolution of ileus. DISCUSSION: Magnesium homeostasis is regulated by gastrointestinal absorption and renal excretion, for which the kidney maintains magnesium equilibrium until creatinine clearance falls below 20 ml/min [1]. Elevated magnesium levels can decrease bowel motility by blocking myenteric neurons and interfere with excitation - contraction coupling of smooth muscle cells as well as serve as a reservoir for continuous magnesium absorption [2]. Our patient suffered acute kidney injury, likely from COVID-19 pneumonia and acute tubular necrosis from shock, placing him at increased risk for hypermagnesemia. One retrospective study identified that patients with COVID-19 are more prone to the development of hypermagnesemia, which is associated with renal failure and increased risk of mortality [3]. The magnesium load from magnesium citrate in our patient created for a seemingly out of proportion effect of hypermagnesemia-induced paralytic ileus and presumably a magnesium reservoir, refractory to conservative measures. CONCLUSIONS: The use of magnesium containing bowel regimens should be considered with caution due to the possibility of hypermagnesemia in at-risk patients, which may result in paralytic ileus and other sequelae. Hypermagnesemia reduces colonic peristalsis and interferes with magnesium equilibrium, prolonging its effects. There are rare case reports in the literature discussing this phenomenon, but should be further evaluated for specific patient susceptibility and effects on morbidity and mortality. Reference #1 Cascella, M. (2022, February 5). Hypermagnesemia. StatPearls [Internet]. Retrieved March 16, 2022, from https//www.ncbi.nlm.nih.gov/books/NBK549811/ Reference #2 Bokhari, S., Siriki, R., Teran, F., & Batuman, V. (2018, September 8). Fatal Hypermagnesemia due to laxative use. The American Journal of the Medical Sciences. Retrieved March 16, 2022, from https//www.amjmedsci.org/article/S0002-9629(17)30467-6/fulltext Reference #3 Stevens, J. S., Moses, A. A., Nickolas, T. L., Husain, S. A., & Mohan, S. (2021, July 29). Increased mortality associated with hypermagnesemia in severe covid-19 illness. American Society of Nephrology. Retrieved March 16, 2022, from https//kidney360.asnjournals.org/content/2/7/1087 DISCLOSURES No relevant relationships by Adnan Abbasi No relevant relationships by Sarah Upson