Acute symptomatic hyponatremia in a flight attendant.

Acute symptomatic hyponatremia after thiazide diuretic initiation is a medical emergency. Here we describe the case of a flight attendant who developed acute hyponatremia during a flight and the potential risk factors for developing this condition. A 57-year-old flight attendant with history of essential hypertension was recently started on a thiazide diuretic. As she did routinely when working, she increased her water intake during a flight from London to Mexico City. She complained of nausea and headache during the flight. Upon arrival, she developed severe disorientation and presented to the hospital emergency room (ER) with a Glasgow scale of 12, hypoxia, and a generalized tonic clonic seizure. Her laboratory results on arrival were consistent with severe hyponatremia (serum Na 116 mEql/L) and severe cerebral edema by CT scan. She was treated with hypertonic saline, with complete resolution of the neurologic symptoms. We describe high water intake and hypoxia related to decreased partial pressure of oxygen in the cabin as the two main risk factors for thiazide-induced acute hyponatremia in this case.