FRI350 Prolonged Transient Central Diabetes Insipidus Induced By Traumatic Brain Injury

Disclosure: R. Marques: None. S. Sharma: None. B.S. Flores Chang: None. A. Sajan: None. Introduction: Central diabetes insipidus (CDI) is a rare complication of traumatic brain injury (TBI). Most cases of CDI due to TBI are transient and resolve within 2-5 days. We report a patient with prolonged transient CDI which lasted for 35 days after sustaining a gunshot wound to the head. Case Description: A 17-year-old male with no past medical history presented after gunshot wound in the head. He had comminuted fractures of the right temporal bone, right zygomatic arch, greater and lesser rings of sphenoid bone, right maxillary sinus, right medial orbital wall, right orbital floor and bilateral frontal sinuses. A computerized tomography of head showed subarachnoid haemorrhage of the frontal lobes as well as subdural haemorrhage of right parietal lobe, right falx cerebri and left cerebral hemisphere. On hospital day 2, he had an intracranial pressure monitor placed which was unremarkable. He underwent right hemicraniectomy with debridement and washout on hospital day 3. Shortly afterwards, his urine output increased to >500 cc/hr with serum sodium of 172 mEq/L [135-145], serum osmolality 307 mOsmol/kg [270-295], and urine osmolality of 117 mOsm/kg [300-900]; consistent with CDI. He was acutely treated with intravenous desmopressin with resolution of hypernatremia. During the next five weeks of his 3-month hospitalization, he continued to have polyuria with specific gravity as low as 1.003 [1.005-1.030], and occasional hypernatremia, with a peak serum sodium of 150 mEq/L. Intranasal desmopressin as well as free water supplementation were given daily to alleviate his polyuria and hypernatremia. Evaluation of anterior pituitary function was normal except for decreased gonadotrophins. His polyuria resolved after five weeks, and labs showed urine osmolality of 530 mOsm/kg with serum sodium 138 mEq/L and urine specific gravity 1.010, consistent with resolution of CDI. Intranasal desmopressin was discontinued. His serum sodium remained stable without desmopressin for the next 7 weeks with serum sodium at discharge of 141 mEq/L. Discussion: The damage of the hypothalamic vasopressin-producing neurons, their axons or the posterior pituitary results in permanent post-TBI CDI. In cases of transient CDI, the pathogenesis is likely related to small vessel damage or inflammatory edema rather than direct neuronal damage. In our case, the patient initially developed hypernatremia and polyuria from acute CDI due to hemicraniectomy with debridement and washout. He continued to have prolonged transient CDI due to the extensive intracranial hemorrhage and edema. The CDI resolved with desmopressin (both intravenous and intranasal) and fluid replacement. Transient CDI is a rare complication intracranial haemorrhage. Our case highlights that the severity of TBI may correlate with the duration of transient CDI. Presentation: Friday, June 16, 2023