Near death by milk of magnesia

High-magnesium exposure to bullfrog heart causes ST segment elevation

Hypermagnesemia occurs in elderly people or patients with renal insufficiency after excessive ingestion of magnesium-containing laxatives. In addition to typical electrocardiogram (ECG) findings caused by conduction defects, changes in the ST segments and T waves are also observed in patients with severe hypermagnesemia. This suggested the involvement of similar pathophysiology to acute myocardial infarction, as we previously demonstrated using burn-induced subepicardial injury model in frog hearts. In the present study, by exposing the bullfrog heart to high-magnesium solution, we reproduced prominent ST segment changes in ECG as actually observed in patients with severe hypermagnesemia. In addition to the great increase in the T waves, the ECG showed a marked elevation of the ST segments and the cardiac action potential demonstrated a marked shift of the resting membrane potential to the depolarized side. High-magnesium exposure did not affect the abundance of Na⁺/K⁺-ATPase proteins. However, the pharmacological stimulation of Na⁺/K⁺-ATPase activity by insulin quickly retrieved the elevated ST segments in ECG. From these results, the functional blockade of Na⁺/K⁺-ATPase activity by magnesium ions was thought to be responsible for generating the potassium concentration gradient and the subsequent ST segment changes.

Severe Hypermagnesemia with Normal Renal Function Can Improve with Symptomatic Treatment

Hypermagnesemia is a rare disorder and commonly occurs in patients with renal dysfunction. Supportive therapy for hypermagnesemia consists of administration of high-volume fluids, calcium preparation, diuretics, and, in severe cases, hemodialysis. Few reports have described severe hypermagnesemia patients with normal renal function who improved without hemodialysis. A 56-year-old woman presented with a history of constipation in spite of taking constipation medicine, including MgO. She was brought to our emergency department due to vomiting and diffuse distension of the abdomen. Sudden vomiting, weakness, and lower level of consciousness occurred during examination. Her blood pressure dropped to 77/34 mmHg, and deep tendon reflexes of the limbs disappeared. Abdominal computed tomography showed bowel distension with wall edema, and biochemical testing showed serum Mg at 13.5 mg/dl. She was diagnosed with severe hypermagnesemia associated with intestinal obstruction and administered intravenous loop diuretics and calcium preparation in addition to high volumes of normal saline. As the serum Mg level steadily declined, her level of consciousness returned to usual. This case suggests that severe hypermagnesemia can occur in patients with normal renal function and constipation under MgO. Severe hypermagnesemia with normal renal function can improve with symptomatic treatment without hemodialysis.