Diabetes insipidus as a complication after pituitary surgery.

BACKGROUND: A 28-year-old woman presented with new-onset vertigo and diplopia that had started 2 weeks previously. An MRI scan of the brain revealed an 11 x 9 x 9 mm sellar mass that extended into the suprasellar region. Evaluation of pituitary function showed mild central hypothyroidism and secondary adrenal insufficiency. The patient underwent trans-sphenoidal resection of the mass without any significant intraoperative complications. On postoperative day 1 she abruptly developed polyuria, hypernatremia and urine hypo-osmolality. INVESTIGATIONS: Measurements of plasma and urine osmolality, urine specific gravity, and serum sodium levels. DIAGNOSIS: Postoperative diabetes insipidus with a triphasic pattern. MANAGEMENT: The patient's diabetes insipidus was initially treated with intravenous desmopressin, and her fluid status, serum sodium levels, and serum and urine osmolality were carefully monitored. During the second, antidiuretic phase, desmopressin was discontinued and the patient's fluid intake was restricted. After recurrence of diabetes insipidus during the third phase, the patient was treated with intranasal desmopressin and was discharged. She remains on desmopressin therapy for chronic diabetes insipidus.