Hypermagnesemia-induced Paralytic Ileus

Hypermagnesemia is a well-known cause of hypotension and cardiac dysfunction but not well recognized is the induction of paralytic ileus. This report details the second and third adult patients reported with hypermagnesemia-induced paralytic ileus. The first patient was a 65-year-old white woman with normal renal function, who had consumed large amounts of magnesium citrate and milk of magnesia. As magnesium blood level fell from 5.1 mg/dl on admission to 2.4 mg/dl on day 3, the vomiting, obstipation, and abdominal distension resolved. The second patient was a 67-year-old woman with mild renal insufficiency, who consumed a large amount of Epsom salts containing magnesium sulfate to treat her constipation. Magnesium levels of 8.1 mg/dl on admission fell to below 3.1 mg/dl on the third hospital day and the paralytic ileus resolved. Mechanical obstruction was ruled out by colonoscopy, gastrographin enema, and barium small bowel series in both patients. Although the clinical findings of muscle weakness, flaccid paralysis, respiratory muscle paralysis or cardiac arrest due to hypermagnesemia are well described in the literature, intestinal smooth muscle dysfunction leading to paralytic ileus has only been reported in one other adult patient. The laboratory and clinical course of these two patients strongly suggest a causal relationship between hypermagnesemia and paralytic ileus.