Delayed onset arginine vasopressin deficiency after traumatic brain injury.

Summary: Delayed arginine vasopressin deficiency (AVP-D) can present in patients following traumatic brain injury (TBI) and may occur years after the trauma, presenting with nonspecific symptoms. The objective of this case is to highlight the importance of considering the delayed onset AVP-D in patients with a history of TBI. We report a case of a patient who had sustained severe traumatic brain injury 8 years before and who presented with polydipsia, behavioural disorder and frequent falls during the last 3 months. The diagnosis of AVP-D was confirmed by water restriction with a positive response to desmopressin, and pituitary MRI showed an absent spontaneous posterior hyperintensity on T1WI. Follow-up confirmed permanent diabetes insipidus as well as a suspected anterior pituitary deficiency. Pituitary dysfunction occurs following TBI and is correlated with severity. As in our case, symptoms are generally non-specific and are difficult to explore given the patient's neurologic sequelae. MRI 8 years post trauma showed changes in pituitary morphology. Some authors have proposed the need for active screening of post-TBI patients. This case highlights the need for clinicians to be aware that AVP-D can occur years after traumatic brain injury.

Learning Points: Delayed onset post-traumatic arginine vasopressin deficiency may occur in patients with TBI and is correlated with the severity. The clinical picture is usually non-specific and diagnosis of AVP-D is challenging in non-verbal patients. An active screening for pituitary dysfunction is warranted in TBI patients and should be extended should one hormone deficit be identified.