Assessment of hypothalamo-pituitary axis in early phase of severe cranioencephalic brain injury

To assess early pituitary function in a sequential cohort of critical care patients after severe traumatic brain injury (TBI). This was a prospective observational study. The pituitary function was always tested on the third day after TBI. Neurocritical intensive care unit (ICU) in a University hospital. A total of 136 adult patients with severe TBI (range, 16-65 years) enrolled over a 2 year and 9 month period having a stay in the ICU treated than 48 hours. None. MEASUREMENTS AND DATA COLLECTED: The following data were recorded within the first 72 hours after injury: demographic variables, injury severity, neuromonitoring data, systemic secondary brain insults, use of vasoactive drugs and type of TBI according to the computerized tomography (CT) scan findings. Pituitary function was evaluated by measurement of both the pituitary and target organ hormones, with the exception of the somatotrophic function, which was assessed by measurement of basal serum values of insulin-like growth factor-I (IGF-I). Pituitary dysfunction was observed in 101 patients (74.2%). Seventy-nine patients (58%) had impairment of only one pituitary axis, the axes being affected as follows: gonadotropic 63.7% (87 patients), thyrotropic 8.8% (12 patients) and corticotropic 0.7% (1 patient). Low IGF-1 plasmatic levels in accordance to the patient's age were observed in 90 patients (66.7%). However, only 26 of them had a value below 90 ng/ml. Our data show that pituitary dysfunction occurs early and with high frequency after severe TBI, but the real significance of these findings still needs to be elucidated.