What causes exogenous corticosteroid related perioperative adrenal insufficiency?
The administration of exogenous corticosteroids can interfere with the normal function of the hypothalamic–pituitary–adrenal (HPA) axis and blunt endogenous cortisol excretion. With stress, the adrenal output blunted by exogenous corticosteroids may become inadequate to support physiologic demands, which include vascular tone and maintenance of blood pressure. The following patients are at risk for corticosteroid-related adrenal insufficiency:
• Patients with features of Cushing’s syndrome (e.g., moon faces, buffalo hump).
• Patients on a prednisone dose (or equivalent of another corticosteroid) of: ≥20 mg daily for ≥5 days or >5 mg daily for ≥30 days.
If there is any concern about whether clinically-important adrenal insufficiency may occur, an adrenal stimulation test should be performed or the patient should receive stress-dose steroids empirically. Patients who become adrenally insufficient during stress (infection, trauma) usually become hypotensive (systolic <90 mm Hg) in spite of fluid resuscitation. These patients should be placed on intravenous (IV) hydrocortisone 100 mg every 8 hours with subsequent tapering once the stress resolves. Tapering is best achieved by lowering the dose and not the frequency (i.e., every 8 hours) of hydrocortisone.