The Altered Adrenal Axis and Treatment With Glucocorticoids During Critical Illness

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Critical illness is generally hallmarked by activation of the hypothalamic- pituitary-adrenal axis. The development of very high levels of cortisol has been associated with severe illness and a raised risk of death. Likewise, a response that is inadequate relative to the degree of stress, termed relative adrenal insufficiency (also known as critical-illness-related corticosteroid insufficiency) has been associated with increased mortality.

...Both very high and very low cortisol levels have been associated with increased mortality from critical illness.^[21] This finding suggests that appropriate activation of the HPA axis is a determining factor for survival. High cortisol levels reflect severe stress, whereas low levels, at baseline and/ or upon ACTH stimulation, could point to an inability to sufficiently respond to stress.^[22] This effect is termed relative adrenal insufficiency (also known as critical-illness-related corticosteroid insufficiency)...

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The Altered Adrenal Axis and Treatment With Glucocorticoids During Critical Illness