Severe Cerebral Salt Wasting Complicating Arginine Vasopressin Deficiency After Traumatic Brain Injury.

Disturbances of water and sodium homeostasis may occur after traumatic brain injury. We report a 20-month-old girl who had a disturbance of water balance consisting of arginine vasopressin deficiency (AVP-D), extreme cerebral salt wasting (CSW), and finally permanent AVP-D following severe traumatic head injury. Magnetic resonance imaging of the brain showed transection of the pituitary stalk and the absence of a posterior pituitary bright spot. Her fluid balance disorder was also complicated by ACTH and TSH deficiency. The CSW phase was characterized by severe hyponatremia with dramatic polyuria and natriuresis and required aggressive fluid replacement with hypertonic saline in addition to vasopressin infusion and fludrocortisone. This case highlights the dynamic nature of fluid balance disorders after brain injury, the importance of recognizing the distinctive patterns of plasma and urine parameters in each condition, and the aggressive management required to treat severe cerebral salt wasting.