Hypothalamic-pituitary dysfunction in critically ill patients with traumatic and nontraumatic brain injury

Background: A significant number of studies have shown that critically ill patients with brain injury (BI) frequently exhibit abnormal pituitary hormonal responses during the immediate postinjury period. Discussion: The elucidation of endocrine alterations depends on the criteria used, the diagnostic tests applied, and the timing of testing in relation to BI. The pattern of the detected hormonal abnormalities shows considerable variability. Altered endocrine responses are due mostly to hypothalamic changes rather than to pituitary dysfunction. Several studies have examined the correlation between hormonal alterations and BI severity, but the results are inconsistent. Furthermore, it remains currently unclear whether and how pituitary abnormalities adversely affect the clinical course of BI patients during the period of critical illness. On the basis of current knowledge, with the exception of clinically significant relative adrenal deficiency and diabetes insipidus, the other endocrine alterations do not seem to require any therapeutic intervention in severely ill BI patients. It is also uncertain whether hormonal abnormalities detected in the early post-BI period persist for the rest of these patients' lives. Conclusions: In view of current evidence indicating a high incidence of pituitary dysfunction even years following BI it is recommended that repetition of endocrine evaluation should be performed during the rehabilitation phase in all patients.