Endocrine Abstracts

Pituitary hormone abnormalities have been reported in up to 50% of survivors of traumatic brain injury (TBI), tested several months or longer after the event. No information is available on the frequency of hypopituitarism in the immediate post-TBI period.

We studied 50 consecutive patients who were admitted to the neurosurgical unit with severe or moderate TBI [initial Glasgow Coma Scale (GCS) score 3-13]. Testing was performed at a median of 12 days post TBI (range 7-20). Growth hormone (GH) and adreno-corticotrophin hormone (ACTH) reserves were assessed using the glucagon stimulation test (GST). Baseline thyroid function, prolactin, IGF-1, gonadotrophins, testosterone or estradiol, plasma sodium, plasma and urine osmolalities or standard water deprivation test were performed. 31 matched controls underwent GST for GH and cortisol responses; other parameters were compared to local reference ranges.

In controls, a normal response was a stimulated GH peak of more than 5 microgram per litre (μg/l) and cortisol greater than 450 nanomole per litre (nmol/l) following glucagon stimulation. Nine TBI patients had GH response less than 5 μg/l, 3 with severe GH deficiency (less than 3 μg/l). 8 patients had cortisol responses less than 450 nmol/l, including 2 with basal cortisol values less than 50 nmol/l. GH and cortisol deficiencies were not related to age, body-mass index, computerised tomography appearance, GCS score or IGF-1 (p > 0.05). 40 patients had gonadotrophins deficiency. In males testosterone level correlated positively with GCS (r = + 0.32, p = 0.04). 1 patient had thyrotrophin deficiency. Hyperprolactinemia was present in 28 patients. Thirteen patients had cranial diabetes insipidus and 7 had SIADH.

Our findings show that pituitary hormone abnormalities occur early and frequently following TBI. These abnormalities may have implications for recovery and rehabilitation. A follow-up of this cohort is in progress to determine the natural history of post-traumatic hypopituitarism.