Eosinophilia as a marker of adrenal insufficiency in the surgical intensive care unit.

Because hemodynamic instability may have several causes in critically ill patients, adrenal insufficiency may not be readily diagnosed. Eosinophilia has been described in patients with chronic adrenal insufficiency but not in critically ill patients. The goal of this study was to determine whether eosinophilia could serve as a marker of adrenal insufficiency in critically ill patients.During a 1-year period, all surgical patients admitted to the surgical intensive care unit with an eosinophil count greater than 3 percent were prospectively studied. To diagnose adrenal insufficiency, the synthetic corticotropin (cosyntropin) stimulation test was used.Eosinophilia was diagnosed in 31 patients, 7 (23 percent) of whom had adrenal insufficiency. The mean time interval to diagnosis was 13.7 days (range, 4 to 39 days). In 82 percent of the patients treated with hydrocortisone, a response was evidenced within 24 hours of treatment by a decrease in the required inotropic support by more than 50 percent, an increase in the mean arterial blood pressure of more than 25 percent, or both.New-onset eosinophilia may be a useful marker for adrenal insufficiency. Prompt testing and diagnosis may avoid the occurrence of a treatable, life-threatening condition.