Prevalence of Anterior Pituitary Dysfunction in Patients following Traumatic Brain Injury in a German Multi-centre Screening Program

Abstract

We determined the prevalence of anterior pituitary dysfunction in a multi-centre screening program across five German endocrine centres in patients rehabilitating from TBI (GCS<13). 246 patients (39+/-14 yrs; 133 males, 12+/-8 months after TBI) underwent a series of baseline endocrine tests with central assessment of TSH, free T4, prolactin, LH, FSH, testosterone (m), estradiol (f), cortisol, GH, and IGF-I. If IGF-I was <-2 SDS dynamic testing was performed. GHD was defined according to BMI-dependent cut-off values for GH response to GHRH+arginine of <4.2, <8.0 and <11.5 ng/ml in obese, overweight and lean subjects, respectively, or <3 micro g/l in ITT. Hypocortisolism was suggested when basal cortisol was <200 nmol/l and confirmed by ITT (peak<500 nmol/l). In TBI patients some degree of impaired pituitary function was shown in 21% (n=52/246). Total, multiple and isolated deficits were present in 1%, 2% and 18%, respectively. 19% had an IGF-I of <-1 SDS, 9% of <-2 SDS. In 5% GHD was confirmed. 9% had hypogonadism. 4% had hypocortisolism and 1% of patients had confirmed ACTH-deficiency. 12% had TSH-deficiency. In summary, in this large series carried out on an unselected group of TBI survivors we have found hypopituitarism in every fifth patient with predominantly secondary hypogonadism and hypothyreosis. Regarding somatotrope insufficiency IGF-I is decreased in 50% of GHD patients. These findings strongly suggest that patients who suffer head trauma should routinely undergo endocrine evaluation.