The neuroendocrine response to critical illness is a dynamic process.

Striking alterations in the hypothalamic-anterior pituitary-peripheral hormone axes hallmark the state of critical illness, their severity being associated with high risk for morbidity and mortality. Early endocrine intervention strategies aimed to correct the hormone balance have been shown ineffective or even harmful because of lack of thorough pathophysiologic understanding of these neuroendocrine changes. Extensive research, however, has provided crucial insights, with the demonstration of the biphasic response of the anterior pituitary to the severe stress of critical illness.