Full recovery from extreme hypernatremia in an elderly woman with hyperosmolar hyperglycemic syndrome and abnormal electroencephalogram.

Background: Hyperosmolar hyperglycemic state is a life-threatening endocrine disorder that most commonly affects adults with type 2 diabetes mellitus. The condition results from an osmotic diuresis-induced loss of water exceeding that of sodium. Altered mental status, hypernatremia and hyperglycemia are characteristic features at presentation. Abnormal electroencephalogram findings have been reported. Successful therapy requires judicious fluid replacement and close monitoring.

Case: A 78-year-old Hispanic female with a significant past medical history of type 2 diabetes mellitus was admitted with altered mental status, severe hypernatremia and hyperglycemia. She was diagnosed with hyperosmolar hyperglycemic state, and fluid therapy was started. A continuous electroencephalogram revealed left frontocentral and temporal periodic lateralized epileptiform discharges that resolved as her hypernatremia and dehydration were treated. She survived and was discharged after 1 week of treatment.

Conclusion: Abnormal electroencephalogram findings consistent with nonconvulsive seizure activity may be temporary and reversible and do not suggest a poor prognosis in an elderly patient suffering from hyperosmolar hyperglycemic state and altered mental status.