Extreme hypermagnesemia as a cause of refractory hypotension.

A 62-year-old woman with adequate renal function who consumed large quantities of magnesium citrate presented with lethargy and hypotension. The hypotension was refractory to all conventional therapy. Her serum magnesium was 12.5 meq/litre (normal, 1.5 to 2.5). She was found to have a perforated duodenal ulcer; peritoneal aspirate magnesium concentration was 12.2 meq/litre. Hypotension improved with intravenous calcium and peritoneal dialysis. This case shows that hypermagnesemia may be accompanied by severe refractory hypotension, and that intestinal disease may predispose to hypermagnesemia in patients ingesting large quantities of magnesium despite normal renal function. Dialysis removes excess magnesium and reverses its toxic effects.