Acute Respiratory Failure From Hypermagnesemia Requiring Prolonged Mechanical Ventilation

Electrolyte abnormalities are an underrecognized cause of respiratory failure in the intensive care unit. One such abnormality is a relatively rare phenomenon of hypermagnesemia resulting in paralysis. A 73-year-old Caucasian male patient presented to the emergency department with diffuse abdominal pain of 2-day duration. He received magnesium citrate and gastrointestinal cocktail for his constipation after initial imaging showed constipation. In view of acute worsening, follow-up computed tomography of the abdomen was done, which showed free air in upper abdomen along with free fluid. Hence, he was taken for emergent laparotomy with repair of pyloric ulcer perforation with omental patch. Post procedure course was complicated by sepsis, acute kidney injury, and respiratory failure with hypoxemia and hypercapnia. On physical examination the patient had flaccid paralysis in all his extremities along with absent brain stem reflexes. Extensive workup including imaging of brain failed to reveal diagnosis. On postoperative day 1, the patient was noted to have magnesium level of 9.2 mg/dL (1.6-2.3 mg/dL), which was thought to be cause of flaccid paralysis and respiratory failure. In view of his acute oliguric kidney injury, he was initiated on intermittent hemodialysis, until his magnesium levels were back to its physiologic limits. His paralysis gradually improved over next 48 to 72 hours and he was liberated from ventilator successfully.