6181 Hyperinsulinism in the NICU: a spectrum of disease

Objectives Hypoglycaemia is a common finding in the newborn and may be associated with hyperinsulinism (HI). Congenital HI is a rare cause of neonatal hypoglycaemia and is associated with severe neurodevelopmental impairment.¹ Previous reports on neonatal HI focus on congenital HI rather than the more commonly presenting transient HI. The primary objective of this study is to describe a cohort of neonates with hyperinsulinism from a neonatal, rather than a supra-specialist perspective. Methods We conducted a service evaluation of the management of neonatal hyperinsulinism in a level 3 Neonatal Intensive Care Unit, over seven years (1/2015 – 12/2021). We collected demographic data, maternal health details, information regarding clinical care, associated conditions and follow-up. The cohort was subdivided into subgroups based on clinical severity, gestational age and growth. Clinical severity was defined as: (1) Severe: treated with diazoxide, (2) Moderately severe: clinically worrying HI without diazoxide, (3) Mild: biochemical evidence of HI without clinically worrying criteria. Results 99 cases identified – Severe(n=20), Moderately-severe(n=30), Mild(n=49). 77% were born locally. Hypoglycaemia was the primary reason for admission in 58% of locally born and 30% of transferred from other hospitals. 12% of infants were Large for gestational age (LGA), 35% Small for Gestational Age (SGA), 42% preterm (<37 weeks), and 17% had diabetic mothers. Birthweight z-score, gestational age, and maternal diabetes did not influence clinical severity. When exploring subgroups of clinical severity, age on diagnosis was lower in Mild infants, compared to Severe (p=0.008). Length of admission was longer for Severe and Moderate compared to Mild(p<0.001). Severe infants received a higher maximum strength of dextrose compared to Moderate and Mild(p<0.001). Glucose requirement on diagnosis was higher in Severe(9.0 ± 5.0mg/kg/min) and Moderate(7.4 ± 3.6mg/kg/min), compared to Mild (5.3 ± 2.3mg/kg/min)(p<0.001). Severe infants had not established full enteral feeds when started on diazoxide, with a mean glucose requirement of 13.2±4.8mg/kg/min. The Severe group achieved full enteral feeds on day 26±15, significantly later than the Moderate group (11±7, p<0.0001). Conclusion This study highlights the diversity of infants with HI cared for in the NICU. SGA, LGA and preterm infants may be at increased risk from both HI and limited availability of alternative fuels.² Management of HI is challenging, as the decision to treat with diazoxide is not straightforward and is influenced by multiple objective and subjective variables. Further research is needed into larger cohorts from different centres to explore the range of clinical practice, and long-term outcomes of this diverse group of infants. References Martino, Sartorelli, Gragnaniello, Burlina. Congenital hyperinsulinism in clinical practice: from biochemical pathophysiology to new monitoring techniques, 23 September 2022. Stanley, Thornton, De Leon. New approaches to screening and management of neonatal hypoglycemia based on improved understanding of the molecular mechanism of hypoglycemia, 10 March 2023.