The syndrome of inappropriate secretion of antidiuretic hormone in the maxillofacial trauma patient.

The maxillofacial trauma patient whose neurologic status undergoes a rapid and serious deterioration may have a severe hyponatremia secondary to the inappropriate secretion of antidiuretic hormone (SIADH). Other causes of hyponatremia must be ruled out, especially posttraumatic cerebral salt wasting, which necessitates a different mode of therapy. A case of SIADH is reported, and the work-up and differential diagnosis of posttraumatic hyponatremia are discussed.