Introduction: 
Hyponatremia is a common electrolyte disturbance encountered in the postoperative period. However, severe hyponatremia, defined as serum sodium <120 mmol/L, following surgery is rare.1 If untreated it can lead to serious neurologic complications including encephalopathy, seizures, and death.  Conversely, a rapid correction of sodium levels may result in a major neurological sequalae due to osmotic demyelination syndrome.1 Thus, it is important for perioperative clinicians to be familiar with the appropriate management of severe hyponatremia. Here, we present a patient who developed neurological dysfunction due to severe hyponatremia following carotid endarterectomy (CEA) surgery. Using this case example, we describe the pathophysiological mechanisms that place these patients at a higher risk for the development of this complication and review the clinical management of severe hyponatremia.
HIPPA Authorization: A written HIPAA authorization consent was obtained from the patient for the publication of this manuscript.