Prevalence of hypopituitarism and growth hormone deficiency in adults long‐term after severe traumatic brain injury

Abstract

Traumatic brain injury (TBI) has been associated with hypopituitarism and GH deficiency. However, TBI-mediated hypopituitarism may be more frequent than previously thought. The present work, performed in patients with severe TBI at least 1 year before, had three aims: (i) to evaluate the prevalence of hypopituitarism, (ii) in particular to evaluate the prevalence of GH deficiency, and (iii) to compare three different tests of GH reserve in this cohort. From a nonselected group of 249 patients admitted to our Clinical Centre for severe TBI over the last 5 years, 200 of them answered a custom made questionnaire of symptoms of hypopituitarism enclosed in the invitation letter to participate in the study. A total of 170 (99 men and 14 women), accepted to participate in the study (study cohort); 57 had normal questionnaires and were not further studied, 14 discontinued the study, and 99 attended the hospital for dynamic tests of pituitary hormone deficiencies. From these, 44 subjects with IGF-I in the lower range were tested with GHRH+GHRP-6; ITT; and glucagon tests of GH reserve, on three different occasions. Pituitary hormones plus IGF-I and target gland hormones were analysed. With regard to the initial cohort of 170 subjects (100%), three (1.7%) showed diabetes insipidus; 10 (5.8%) TSH deficiency, 11 (6.4%) ACTH deficiency and 29 (17%) gonadotrophin deficiency. In 10 subjects (5.8%), GH deficiency was diagnosed by strict criteria. Finally, 15 (8.8%) showed combined deficit of several hormones. After severe head trauma, gonadotrophin deficiency was the most common pituitary deficit. GH deficiency showed a prevalence similar to ACTH and TSH deficits, i.e. near 6% of the cohort. Taken together, 24.7% of the subjects studied showed any type of pituitary hormone deficiency.