Endocrine Abstracts

Introduction: Congenital hyperinsulinism (CHI) is a rare and important cause of neonatal hypoglycaemia characterised by hypoglycaemia secondary to inappropriate insulin secretion. Fluctuating glycaemic trends in early neonatal life and time-sensitive biochemical testing present clinical challenges. Management of CHI is complicated, requiring communication between multiple specialist teams. Early detection of hypoglycaemia prevents neurodevelopmental sequelae.

Objective: To evaluate CHI diagnosis & management in a level 3 neonatal unit, and identify practice patterns/knowledge gaps among specialists in line with 2023 UK Collaborative Consensus.

Methods: All neonates diagnosed with hyperinsulinism between March 2020 and March 2024 at Luton NICU were identified retrospectively using Badgernet database. Data included patient demographics, gestational age, birth weight, ethnicity, maternal and family history, hypoglycemia screening tests, medical interventions (glucose bolus and medications), nutritional sources, glucose infusion rate (GIR), day of life at diagnosis, genetics tests requested, glucose monitoring, dietetic reviews and neurodevelopmental follow-up.

Results: We identified 30 neonates with CHI (gestational age 27+6 weeks - 40+6 weeks), average weight was 2.69 kg (0.62 kg - 5.19 kg). The majority were full term (19/30), and boys (20/30). Insulin level was sent for 29/30 infants; average insulin level was 16.2mIU/l. First line investigations including growth hormone (0/30), lactate (24/30), and c-peptide (16/30) were frequently missed. 14/30 received 20% dextrose via central line with mean GIR 13.7 mg/kg/min (6.9-17.7 mg/kg/min). 18/30 babies were commenced on medication (diazoxide & chlorothiazide) after appropriate cardiac monitoring. One infant had a genetic cause for CHI and received early input from a CHI quaternary centre.

Conclusion: CHI is often overlooked; mean age at diagnosis was 11.7 days with average of 5 hypo-episodes/neonate recorded. Testing for C-peptide was missed in 53.3%, free fatty acids (FFA) in 40% and ketones in 36%. Importance of FFA/ketones testing should be reiterated to aid faster diagnosis, as insulin may be undetectable (20%), and levels may not correlate with hypoglycaemic severity. Amino acids (57.6%) and urine organic acids (64.7%) needed repetition due to prematurity or insufficient sampling, wasting time and resources. Developmental follow-up is crucial, as four infants(18.1%) were detected with developmental delay. Only 16.6% of infants were exclusively breastfed on discharge, highlighting need for better breastfeeding support.