A 48-year-old man with a history of asthma treated with intermittent steroids, and a history of kidney stones, is admitted to the ICU with urosepsis. He is intubated, started on antibiotics, and fluid resuscitated with 30 mL/kg of normal saline. Despite this therapy he becomes increasingly hypotensive requiring escalating vasopressor doses. An ACTH stimulation test is performed revealing a baseline cortisol of 10 µg/dL and a 30-minute peak of 16 µg/dL.
Which of the following interventions is most appropriate given the ACTH test results?
A. Administer corticosteroids, she is adrenally insufficientCorrect Answer: A
Administering ACTH (cosyntropin) is a way of interrogating the hypothalamic-pituitary-adrenal axis to determine its function in response to systemic stress. The ACTH stimulation test involves measuring a baseline (random) cortisol level, administering 250 µg of ACTH, and measuring the rise in serum cortisol after 30 to 60 minutes. A peak cortisol of 18 to 20 µg/dL is considered a normal response to ACTH stimulation and excludes primary and nearly all cases of secondary adrenal insufficiency. In critical illness an incremental increase of less than 9 µg/dL is the most sensitive and specific cutoff of identify nonresponders. Thus, in this patient a peak level of 16 µg/dL and rise of only 6 µg/dL indicate adrenal insufficiency, and she would likely benefit from corticosteroids. There is no indication that repeat testing is necessary as long as the peak levels are drawn at the appropriate time. The 250 µg cosyntropin stimulation tests raised the ACTH concentration to 60,000 pg/mL, which dwarfs the physiologic 100 pg/mL of ACTH needed to maximally stimulate the adrenal cortex. However, it is possible that patients who respond to these supra-maximal doses may still be adrenally insufficient when this stimulus is removed. Corticosteroid administration has been shown to be useful in shock reversal in patients with critical illness–related corticosteroid insufficiency.
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