Syndrome of inappropriate secretion of antidiuretic hormone and hyponatremia after spinal surgery.

Hyponatremia caused by an inappropriately high level of antidiuretic hormone secretion after spinal surgery is an uncommon and self-limiting phenomenon that resolves within 2 or 3 weeks. During the early postoperative period, the patient's urine output and serum level of sodium should be monitored closely to prevent possible serious complications of the syndrome of inappropriate secretion of antidiuretic hormone. Symptoms vary depending on the severity of the hyponatremia and can range from mild headache, muscle cramps, nausea, and vomiting to convulsions, coma, and death. Treatment options include fluid restriction, oral intake of salt, and hypertonic saline. It is important that spine surgeons recognize this phenomenon early and treat it appropriately and conservatively to prevent possible serious complications.