Stridor: a rare complication of magnesium sulfate therapy in a pregnant patient

Magnesium sulfate is frequently used in severe preeclampsia and eclampsia for the prevention and reoccurrence of seizure activity. Their adverse effects of magnesium sulfate are minor but it cause respiratory depression and tetany. We report a case of stridor due to laryngospasm as result of hypocalcemia in a pregnant patient on magnesium sulfate therapy. A 30 year old gravida5 para 4 had severe preeclampsia started on magnesium sulfate therapy and to control her hypertension she was on labetalol and nifidipine. One hour after the lower segment cesarean section, she developed severe laryngospasm and stridor, no upper airway secretion but found to have hypocalcemia. She responded to immediate intravenous calcium chloride with dramatic clinical improvement. Patients on magnesium sulfate can have life threatening hypocalcemia and stridor. The calcium channel blockers may augment the hypocalcaemic effect of magnesium sulfate.