Anterior Pituitary Function May Predict Functional and Cognitive Outcome in Patients with Traumatic Brain Injury Undergoing Rehabilitation

Traumatic brain injury (TBI) is the leading cause of death and disability in young adults. Growth hormone-insulin-like growth factor I (GH-IGF-I) system has an important role in the recovery of the central nervous system. The aim of the study was to evaluate the relationship between pituitary function (in particular, the GH-IGF-I axis) and outcome from TBI. We studied 72 patients (56 males; mean age 37.2 +/- 1.8 years) receiving rehabilitation after TBI. According to the Glasgow Coma Scale (GCS), 10 patients had moderate and 52 severe TBI. Ten patients had growth hormone GH deficiency (GHD), 10 LH-FSH, three TSH, and three ACTH deficiency. Overall pituitary dysfunction occurred in 22 (30.5%) patients, with anterior hypopituitarism in 19 (26.4%), isolated diabetes insipidus in one, and isolated hyperprolactinemia in two. GH response to GHRH + ARG (arginine) positively correlated with Functional Independence Measure (FIM D; r = 0.267, p < 0.02) and Level of Cognitive Functioning Scale (LCFS D; r = 0.287, p < 0.01) at discharge, and negatively with Disability Rating Score at discharge (DRS D; r = -0.324, p < 0.005). Unfavorable outcome measures (FIM D, LCFS D, and DRS D) occurred in patients with hypopituitarism as compared with normal pituitary function (p < 0.05). Multiple regression analysis identified both GCS (p < 0.005) and GH peak (p < 0.05) as strong independent predictors of outcome. In conclusion, recovery after TBI may be negatively influenced by concomitant pituitary dysfunction. The GH peak value is an independent predictor of outcome, indicating that recovery during an intensive rehabilitation program after TBI may be positively influenced by normal GH secretion.