Early endocrine alterations reflect prolonged stress and relate to one year functional outcome in patients with severe brain injury

OBJECTIVE: Severe brain injury poses a risk of developing acute and chronic hypopituitarism. Pituitary hormone alterations developed in the early recovery phase after brain injury may have implications for long-term functional recovery. The objective was to assess the pattern and prevalence of pituitary hormone alterations three months after severe brain injury with relation to functional outcome at one year follow-up.

DESIGN: Prospective study at a tertiary university referral centre.

METHODS: A total of 163 patients admitted to neurorehabilitation after severe traumatic (N=111) or non-traumatic (N=52) brain injury were included. Main outcome measures were endocrine alterations 3.3 months (median) after the brain injury and their relationship to functioning and ability of the patients at one year follow-up, as measured by Functional Independence Measure and Glasgow Outcome Scale-Extended.

RESULTS: Three months after the injury, elevated stress hormones (i.e. 30 min. stimulated cortisol, prolactin and/or insulin-like growth factor 1) and/or suppressed gonadal- or thyroid hormones were recorded in 68% and 32% of the patients, respectively. At one year, lower functioning level (Functional Independence Measure) and lower capability of normal life activities (Glasgow Outcome Scale-Extended) were related to both elevated stress hormones (p≤0.01) and reduced gonadal and/or thyroid hormones (p≤0.01) measured at 3 months.

CONCLUSIONS: The present study suggests that brain injury-related endocrine alterations mimicking secondary hypogonadism and hypothyroidism and with elevated stress hormones most probably reflect a prolonged stress response 2 to 5 months after severe brain injury, rather than pituitary insufficiency per se. These endocrine alterations thus seem to reflect a more severe disease state, and relate to one year functional outcome.