BSPED2014 Oral Communications Oral Communications 4 (9 abstracts)
1University Hospital Southampton, Southampton, UK; 2Queen Alexandra Hospital, Portsmouth, UK.
Introduction: Adrenal insufficiency is rare in the neonatal period and if unrecognised may cause life-threatening circulatory collapse. The initial investigations taken at the time of presentation, and prior to the institution of hydrocortisone, are a key step in the diagnostic pathway, and aid the clinician to distinguish adrenal insufficiency from mineralocorticoid resistance or renal tubulopathy. A cortisol measurement at the time of illness is useful to evaluate the adrenal glucocorticoid reserve. Here, we present four cases of neonates presenting with an adrenal crisis where the cortisol result was misleading and could have caused delayed diagnosis or lead to inappropriate discontinuation of hydrocortisone.
Case series: Four male term babies presented with a salt-wasting crisis during the neonatal period. The diagnosis of congenital adrenal hyperplasia secondary to 21-hydroxylase deficiency was subsequently confirmed in each. The table shows the initial biochemical results at presentation and the cortisol assay used. 17-OHP results were available >24 h after presentation.
Case | Age at presentation (days) | Na (135144 mmol/l) | K (3.55.0 mmol/l) | Cortisol (nmol/l) | 17-OHP (nmol/l) | Cortisol assay |
1 | 16 | 116 | 10.4 | 624 | >200 | CBIA |
2 | 17 | 111 | 9.2 | 498 | >800 | CBIA |
3 | 27 | 108 | 10.0 | 687 | >2000 | OSSA |
4 | 12 | 110 | 7.2 | 882 | 44a | OSSA |
CBIA, competitive binding immunoenzymatic assay; OSSA, one-site sandwich assay. | ||||||
aSample taken following hydrocortisone commenced. |
Conclusion: Assay interference from cross-reactivity with adrenal fetal zone steroids is likely to have caused the apparent elevated cortisol measurements. The use of tandem mass spectrometry may address this issue, although new reference ranges will need to be established with this technology. In the interim, the clinician should rely on clinical suspicion and the results of all of the investigations taken at the time of presentation to inform the subsequent management.