Endocrine Abstracts

Background: Traumatic brain injury (TBI) is a major cause of disability and death, and a cause of neuroendocrine dysfunction. Partial or complete pituitary dysfunction is a frequent event occurring in 25–50% of subjects after a TBI as result from damage to either the pituitary or the hypothalamus. This large variability depends on the screening methods and on the difficulty to predict the effects of the trauma on pituitary. Growth hormone deficiency and gonadotropin deficiency are the most frequently documented pituitary dysfunctions after TBI. Also hyperprolactinemia has been documented as result of hypothalamic-pituitary stalk damage.

Aim of the study: Aim of our study was to determine the incidence of pituitary dysfunctions following mild to moderate TBI.

Methods and patients: All subjects followed at the emergency room of our institution 12–6 months before were invited to a screening of pituitary function by measuring: FSH, LH, TSH, IGF-1, Testosterone (T) in (man), 17-beta-estradiol (in women) and PRL. When IGF-1 was below the reference range a GHRH + Arginine test was performed to document a GH deficency. LHRH test was performed when FSH and LH and T or 17-beta-estradiol were below the reference range to document gonadotropin deficiency.

Results: Forty-five subjects aged 18–63 years joined the screening. Single or multiple pituitary failure was found in 14 patients (31%). Hypogonadotropic hypogonadism was documented in 3 males (6.8%), low IGF-1 in 10 patients (22%) and GH insufficiency documented in 3 of 4 patients tested by GHRH + Arginine (7%). One patient displayed a concomitant GH insufficiency and low TSH level while in another subject we found GH deficit and low FSH, LH and testosterone values even if his gonadotropin response was normal after LHRH test. Surprisingly, none of the patients displayed altered PRL values.

Conclusions: Mild to moderate TBI was followed by pituitary dysfunction documented in 13.3% of subjects. Higher frailty of GH and gonadotropin secretion by pituitary was confirmed, while altered PRL secretion was not documented.