Neuroendocrine consequences of traumatic brain injury

Severe to moderate traumatic brain injury (TBI) is associated with a high frequency of morbidity in survivors. The pituitary gland is vulnerable to damage following TBI and long-term neuroendocrine dysfunction is a potential complication. Until recently little has been known about the natural history, presentation and characteristics of hypothalamic-pituitary dysfunction following TBI. This article reviews the emerging body of contemporary data from adult survivors of TBI, which suggests that the prevalence of pituitary hormone problems following head injury may be much more common than previously thought. We also review the epidemiology of childhood TBI and historical case reports that show that pituitary dysfunction has been observed to occur after both mild and severe TBI and may not present clinically until many years after the event. A recent analysis of a large paediatric growth hormone (GH) deficiency patient database highlights fewer than expected registered cases of TBI-related GH deficiency, suggesting that this may be an overlooked phenomenon. This hypothesis is supported by recently published data from the first systematic studies to be carried out in the childhood TBI setting. Given the critical role of anterior pituitary hormones in the regulation of growth and pubertal and neurocognitive development in childhood, early detection of hormone abnormalities is important. We propose that a multidisciplinary approach to follow-up and endocrine assessment is required for the long-term management and rehabilitation of children and adolescents who survive moderate to severe head injury.