Effects of Head Trauma and Brain Injury on Neuroendocrinologic Function

Patients with traumatic injury, admitted within 48 hours of their accident were studied to determine the association between the severity of injury assessed by standard techniques and sympathetic nervous function in order to determine weather catecholamine levels can be used to predict patient outcome, excessive catecholamine release contributes to morbidity and mortality, and brain injury andor sympathetic nervous system activation contributes to pituitary dysfunction. The conclusion of the investigation of the catecholamine response to brain injury revealed that in 61 traumatically brain-injured patients into those universally improved and those who were very likely to have minimal or no improvement or who died. Evaluation of the effects of brain injury on pituitary function demonstrated that the severity of hypogonadism is dependent upon the degree of neurologic impairment, that there is a significant negative correlation between changes in testosterone levels, and finally, that the steroid precursors involved in the testosterone, but not in the cortisol, pathways also becomes subnormal. Investigation of the thyroid dysfunction is also dependent upon the degree of neurologic impairment and that thyroid function abnormalities reflect ultimate outcome. The significant association with catecholamines suggest a role of sympathetic nervous system activation in causing the thyroid function, which is independent of the generalized stress responses.