The challenge of defining relative adrenal insufficiency

Abstract

Defining relative adrenal insufficiency in preterm infants remains a significant challenge for neonatologists. The phenomenon of relative adrenal insufficiency in adults and children has been well described, with normal basal levels of cortisol, yet inadequate response to stress as documented by a blunted response to adrenocorticotropin hormone (ACTH) stimulation.1, 2, 3 In preterm infants, numerous confounding factors make the definition more elusive. Preterm infants developmentally may have low basal cortisol levels in the absence of symptomatology,4 and it is less clear what constitutes an appropriate stress response in the face of an acute illness, such as respiratory distress syndrome or sepsis.5, 6 Similarly, many of the symptoms of relative adrenal insufficiency, such as hypotension and electrolyte abnormalities, are common in this population, with many possible underlying etiologies.