LAUSR

Hypermagnesemia is a rare electrolyte abnormality that is difficult to diagnose because its symptoms are nonspecific. In addition to magnesium administration, renal dysfunction is often a major risk factor associated with the condition; severe intestinal dysfunction is also a known risk factor. However, no cases of hypermagnesemia were observed in the absence of magnesium administration. A 75-year-old woman with cognitive impairment presented to the emergency department with impaired consciousness. The patient was comatose and hypotensive and had a markedly distended abdomen. Her blood pressure was stabilized with infusion; however, the improvement in consciousness was insufficient and somnolence continued. Abdominal computed tomography revealed marked colonic distension due to fecal impaction in the rectum, with wall thickening and pericolonic fat stranding. Blood tests revealed elevated levels of C-reactive protein (10.2 mg/dL), lactate (6.04 mmol/L), and magnesium (5.9 mg/dL). There was no history of ingestion of magnesium-containing preparations; thus, the patient was diagnosed with hypermagnesemia associated with stercoral colitis. Magnesium levels and consciousness improved with the administration of calcium preparations, diuretics, antibiotics, and defecation control. Severe bowel dysfunction can cause hypermagnesemia, even in the absence of magnesium administration.