Abstract
Primary Subject area
Neonatal-Perinatal Medicine
Background
Infants born at low gestational age (GA) often present with a septic shock-like picture in the neonatal intensive care unit (NICU). Some of these premature infants are noticed to exhibit inadequate cortisol levels at such a time of stress, an entity termed ‘relative adrenal insufficiency’ (RAI), which is postulated to compromise the compensatory mechanisms and further circulatory collapse.
Objectives
To review the clinical features and echocardiographic parameters of RAI in preterm infants, and their correlation with adrenocorticotropic hormone (ACTH) stimulation tests in a quaternary NICU over 5 years.
Design/Methods
This is a single centre retrospective study. Infants born at < 32 weeks GA between January 2015 to June 2019, admitted to the British Columbia Women’s Hospital NICU (Vancouver, British Columbia), were reviewed. Infants who presented with a shock-like picture with a cortisol level at this time of stress of < 250 nmol/L were included. Infants who have received corticosteroid prior to cortisol collection were excluded.
Results
There were 798 infants < 32 weeks admitted to the BCWH NICU over a 5 year period, of which 284 had a spot cortisol drawn. We identified 45 eligible infants in our study (5.6% of NICU admissions). Their median (IQR) for GA, birth weight, cortisol level, and age of onset of RAI were 25 weeks (24, 26), 690 g (590, 815), 83 (58, 127), and 13 days of life (8, 24), respectively. Among these infants, 73% developed significant hypotension or respiratory failure (Table 1). 13 infants (28.9%) had echocardiogram performed at the time of cardiopulmonary deterioration, and all had normal left ventricular (LV) fractioning shortening (median [IQR]: 42% [38-49%]) and LV output (median [IQR]: 242 mL/kg/min [155-330 mL/kg/min]). Only 19 infants (42.2%) received hydrocortisone, with a median [range] treatment duration of 2 days [1–8]. Lower cortisol level was associated with lower GA at the presentation of RAI (p=0.049), but not predictive of adverse clinical and laboratory outcomes (Table 2). ACTH stimulation tests were performed in 20 (44.5%) infants and 3 (15%) were found to be abnormal, and results were not correlated with clinical features.
Conclusion
In our cohort, we identified 5% of NICU admission with RAI, based on the cut-off of cortisol < 250 nmol/L at the time of shock-like presentation. Lower cortisol level was associated with lower GA at the presentation of RAI. Further prospective study with a well-defined protocol is needed to understand the use of cortisol and its clinical implications.
On the Term “Relative Adrenal Insufficiency”—or What Do We Really Measure with Adrenal Stimulation Tests?
