The syndrome of inappropriate secretion of antidiuretic hormone in the pharyngeal flap operation.

A prospective study was undertaken to determine whether there was a relationship between the pharyngeal flap operation and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). From August 1982 to November 1983, 25 patients underwent pharyngeal flap procedures. They were compared to a control group made up of five patients who underwent major cleft lip revisions. Twelve of the twenty-five patients (48%) who underwent pharyngeal flap procedures had inappropriately elevated serum ADH levels, low serum osmolality, and hyponatremia in the postoperative period. There was a statistically significant (p less than 0.001) drop in the serum sodium levels in the pharyngeal flap group from the preoperative to postoperative period. There was neither a statistically significant change in the serum sodium levels nor inappropriate elevation of ADH levels in the control group. Two patients who underwent pharyngeal flap procedures developed SIADH. To our knowledge this complication has not been reported in association with the pharyngeal flap operation. No specific causes were found that would explain why SIADH developed.