You are taking care of a 35-year-old man with Crohn’s disease. His symptoms were somewhat controlled with 30 mg of oral prednisone daily, but he developed a chronic, long-segment ileal stricture that required an open ileocolectomy with primary anastomosis. You are writing his postoperative orders.
1. What is the mechanism of acute adrenal insufficiency?
2. Should you have given him a “stress” dosage of steroids at the start of the case? Why or why not?
In patients who are glucocorticosteroid dependent, insufficient amounts of corticosteroids or cortisol resistance during critical illness may lead to secondary adrenal insufficiency with eventual hypotension, shock, and death. The pathophysiological mechanism for this hypotension cascade is not entirely clear, but is likely due to enhanced prostacyclin production and its subsequent vasodilatory effects leading to hypotension and shock.
As a general rule of thumb, any patient who has received at least 20 mg of prednisone or its glucocorticoid equivalent (see Table 41-1) for greater than 5 days is at risk for hypothalamus–pituitary–adrenal (HPA) axis suppression. Inhaled glucocorticoids may or may not cause HPA suppression. Patients who are on lower dosages of glucocorticoids may require at least a month to develop HPA suppression. Following tapering of glucocorticoid therapy, it may take patients a year or longer to resume normal HPA axis responses with pituitary function being the first to normalize. If you are uncertain and time permits, these patients are often referred to an endocrinologist for an ACTH stimulation test to see if they secrete normal amounts of cortisol in response to ACTH.
Because this patient was chronically on 30 mg of prednisone, he should receive stress dose steroids postoperatively.
Although the actual incidence of adrenal insufficiency due to lack of exogenous glucocorticoids is likely low, it is a highly preventable cause of morbidity/mortality.
The risk of secondary adrenal insufficiency in glucocorticoid-dependent patients is directly related to the duration and severity of the surgical procedure. Relatively minor procedures that are less than 1 hour long or can be done under local anesthetic have a low degree of physiological stress. A dose of hydrocortisone of 25 mg or its equivalent is a sufficient “stress dosage” for minor procedures. For moderate-stress procedures such as peripheral bypass surgery or a straightforward small bowel resection and anastomosis a dose of 50 to 100 mg of hydrocortisone should be given intravenously prior to or at the time of skin incision. Finally, for high-stress procedures such as a total proctocolectomy or cardiac bypass procedure, a stress dose of 100 mg of hydrocortisone should be given at the start of the procedure.
For minor procedures, the patient should take his or her normal dosage of steroids the morning of surgery and then resume the normal home dosage postoperatively. For moderate-stress procedures, patients should receive 25 mg of hydrocortisone intravenously every 8 ...