Hypoadrenalism is a life-threatening syndrome in critically ill patients. It can be found in patients with chronic adrenal insufficiency as well as those with adrenal suppression who are simply unable to mount the expected stress response to common conditions in the intensive care unit (ICU), including infection, sepsis, trauma, and surgery. Adrenal insufficiency can manifest as a broad number of signs and symptoms including weakness, hyponatremia, hypoglycemia, disruption of acidbase status, and hypotension (specifically hypotension refractory to therapy with pressors). Patients suffering from hypoadrenalism have significantly reduced mortality when this condition is diagnosed and therapy initiated.

The widely accepted test for primary adrenal insufficiency is the cosyntropin stimulation test. Cosyntropin is a synthetic analogue of adrenocorticotropic hormone (ACTH), consisting of the first 24 amino acids of the naturally occurring ACTH. This test consists of a baseline blood sample sent for cortisol level, followed by a single intravenous (IV) dose of 250 μg of cosyntropin, with further blood samples collected at 30 and 60 minutes after administration, although the 30-minute measure may be superfluous as the cortisol levels peak at 60 minutes. There exists some controversy over what constitutes a positive and negative stimulation test, but even the more conservative proponents seem to agree that adrenal insufficiency is not present if the baseline cortisol level is >20 μg/dL and a normal response to cosyntropin stimulation is present (i.e. the cortisol level increases by greater than 9 μg/dL in response to the above test). If a patient meets these criteria, he or she does not have adrenal insufficiency and no supplementation of adrenal hormones is necessary.