In people who survived a severe head injury, about 6% have a genuine lack of growth hormone, similar to other pituitary hormone problems. The researchers used a combo of GHRH and GHRP‑6 to test how much GH the pituitary can still make, and compared it with other standard tests.

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.