[Spinal anesthesia for empty sella syndrome associated with diabetes insipidus--a case report]

A 60-year-old woman was admitted to our hospital for surgical treatment of the left inguinal hernia. She had suffered from diabetes insipidus for ten years, and hormonal study revealed low plasma level of vasopressin. She has been taking nasally desmopressin acetate 5 micrograms twice a day and urinary output has been well controlled around 1200-1400 ml.day-1. CT-scan showed empty sella without any pituitary tumors. There were no evidences of increased intracranial pressure and neurological deficit. Following nasal instillation of desmopressin acetate 5 micrograms one hour before anesthesia, spinal anesthesia was performed with tetracaine 10 mg. Cephalad sensory block assessed by pinprick spread to T6 within 10 minutes. Systolic blood pressure gradually decreased from 120 to 90 mmHg, although no vasoconstrictors were needed. Arterial blood pressure was stable during the surgery. The operation lasted 80 minutes with 650 ml of fluid replacement, blood loss of 50 g and urinary output of 25 ml. She had no postspinal headache nor neurological deficit after surgery. Empty sella syndrome associated with diabetes insipidus is rare. Low spinal anesthesia can be performed safely whenever there is no evidence of increased intracranial pressure, although care should be taken for perioperative fluid and circulatory management.