Necrotizing Enterocolitis in Neonates With Hyperinsulinemic Hypoglycemia Treated With Diazoxide

Variability in Diagnosis and Management of Hypoglycemia in Neonatal Intensive Care Unit

OBJECTIVE

 Hypoglycemia, the most common metabolic derangement in the newborn period remains a contentious issue, not only due to various numerical definitions, but also due to limited therapeutical options which either lack evidence to support their efficacy or are increasingly recognized to lead to adverse reactions in this population. This study aimed to investigate neonatologists' current attitudes in diagnosing and managing transient and persistent hypoglycemia in newborns admitted to the Neonatal Intensive Care Unit (NICU).

METHODS

 A web-based electronic survey which included 34 questions and a clinical vignette was sent to U.S. neonatologists.

RESULTS

 There were 246 survey responses with most respondents using local protocols to manage this condition. The median glucose value used as the numerical definition of hypoglycemia in first 48 hours of life (HOL) for symptomatic and asymptomatic term infants and preterm infants was 45 mg/dL (2.5 mmol/L; 25-60 mg/dL; 1.4-3.3 mmol/L), while after 48 HOL the median value was 50 mg/dL (2.8 mmol/L; 30-70 mg/dL; 1.7-3.9 mmol/L). There were various approaches used to manage transient and persistent hypoglycemia that included dextrose gel, increasing caloric content of the feeds using milk fortifiers, using continuous feedings, formula or complex carbohydrates, and use of various medications such as diazoxide, glucocorticoids, and glucagon.

CONCLUSION

 There is still large variability in current practices related to hypoglycemia. Further research is needed not only to provide evidence to support the values used as a numerical definition for hypoglycemia, but also on the efficacy of current strategies used to manage this condition.

KEY POINTS

· Numerical definition of glucose remains variable.. · Strategies managing transient and persistent hypoglycemia are diverse.. · There is a need for further research to investigate efficacy of various treatment options..

Neonatal hyperinsulinism: a retrospective study of presentation and management in a tertiary neonatal intensive care unit in the UK

OBJECTIVE

Reports of hyperinsulinism typically focus on infants managed by highly specialised services. However, neonates with hyperinsulinism are initially managed by neonatologists and often not referred to specialists. This study aimed to characterise the diversity in presentation and management of these infants.

SETTING

Level 3 neonatal intensive care.

PATIENTS

Neonates with hyperinsulinism, defined as blood glucose <2.8 mmol/mL and insulin level >6 pmol/L.

DESIGN

7-year retrospective study (January 2015-December 2021).

RESULTS

99 cases were identified: severe-treated with diazoxide (20%), moderate-clinically concerning hyperinsulinism not treated with diazoxide (30%), mild-biochemical hyperinsulinism (50%). Birth weight z-score was -1.02±2.30 (mean±SD), 42% were preterm, but neither variable correlated with clinical severity. The severe group received a higher concentration of intravenous glucose (27±12%) compared with the moderate (15±7%) and mild (16±10%) groups (p<0.001). At diagnosis, the intravenous glucose intake was similar in the severe (7.43±5.95 mg/kg/min) and moderate (5.09±3.86 mg/kg/min) groups, but higher compared with the mild group (3.05+/2.21 mg/kg/min) (p<0.001). In the severe group, term infants started diazoxide earlier (9.9±4.3 days) compared with preterm (37±26 days) (p=0.002). The national congenital hyperinsulinism service was consulted for 23% of infants, and 3% were transferred.

CONCLUSIONS

This study highlights the diversity in clinical presentation, severity and prognosis of neonatal hyperinsulinism, irrespective of birth weight and gestational age. More infants were small rather than large for gestational age, and the majority had transient hyperinsulinism and were not referred to the national centre, or treated with diazoxide. Further research is required to understand the breadth of neonatal hyperinsulinism and optimal management.

Low-dose diazoxide is safe and effective in infants with transient hyperinsulinism

OBJECTIVE

Transient hyperinsulinism (THI) is the most common form of recurrent hypoglycaemia in neonates beyond the first week of life. Although self-resolving, treatment can be required. Consensus guidelines recommend the lower end of the diazoxide 5-15 mg/kg/day range in THI to reduce the risk of adverse events. We sought to determine if doses <5 mg/kg/day of diazoxide can be effective in THI.

DESIGN, PATIENTS, MEASURMENTS

Infants with THI (duration <6 months) were treated with low-dose diazoxide from October 2015 to February 2021. Dosing was based on weight at diazoxide start: 2 mg/kg/day in infants 1000-2000 g (cohort 1), 3 mg/kg/day in those 2000-3500 g (cohort 2) and 5 mg/kg/day in those >3500 g.

RESULTS

A total of 73 infants with THI (77% male, 33% preterm, 52% small-for-gestational age) were commenced on diazoxide at a median age of 11 days (range 3-43) for a median duration of 4 months (0.3-6.8), with no difference between cohorts. The mean effective diazoxide dose was 3 mg/kg/day (range 1.5-10); 35% (26/73) required an increase from their starting dose, including 60% (9/15) of cohort 1. There was no association between perinatal stress risk factors or treatment-related characteristics and dose increase. Adverse events occurred in 13 patients (18%); oedema (12%) and hyponatraemia (5%) were the most common. Two infants developed suspected necrotising enterocolitis (NEC); none had pulmonary hypertension.

CONCLUSION

Diazoxide doses <5 mg/kg/day are effective in THI. While the nature of the association between diazoxide and NEC was unclear, other adverse events were mild. We suggest considering starting doses as low as 2-3 mg/kg/day in THI to balance the side effect risk while maintaining euglycaemia.

Standardised practices in the networked management of congenital hyperinsulinism: a UK national collaborative consensus

Congenital hyperinsulinism (CHI) is a condition characterised by severe and recurrent hypoglycaemia in infants and young children caused by inappropriate insulin over-secretion. CHI is of heterogeneous aetiology with a significant genetic component and is often unresponsive to standard medical therapy options. The treatment of CHI can be multifaceted and complex, requiring multidisciplinary input. It is important to manage hypoglycaemia in CHI promptly as the risk of long-term neurodisability arising from neuroglycopaenia is high. The UK CHI consensus on the practice and management of CHI was developed to optimise and harmonise clinical management of patients in centres specialising in CHI as well as in non-specialist centres engaged in collaborative, networked models of care. Using current best practice and a consensus approach, it provides guidance and practical advice in the domains of diagnosis, clinical assessment and treatment to mitigate hypoglycaemia risk and improve long term outcomes for health and well-being.

Watchful waiting versus pharmacological management of small-for-gestational-age infants with hyperinsulinemic hypoglycemia

Introduction

Given that reports on severe diazoxide (DZX) toxicity are increasing, we aimed to understand if the short-term clinical outcomes of small-for-gestational-age (SGA) infants with hyperinsulinemic hypoglycemia (HH) managed primarily by supportive care, termed watchful waiting (WW), are different from those treated with DZX.

Method

A real-life observational cohort study was conducted from 1 September 2014 to 30 September 2020. The WW or DZX management decision was based on clinical and biochemical criteria. We compared central line duration (CLD), postnatal length of stay (LOS), and total intervention days (TIDs) among SGA-HH infants treated with DZX versus those on a WW approach. Fasting studies determined the resolution of HH.

Result

Among 71,836 live births, 11,493 were SGA, and 51 SGA infants had HH. There were 26 and 25 SGA-HH infants in the DZX and WW groups, respectively. Clinical and biochemical parameters were similar between groups. The median day of DZX initiation was day 10 of life (range 4-32), at a median dose of 4 mg/kg/day (range 3-10). All infants underwent fasting studies. Median CLD [DZX, 15 days (6-27) vs. WW, 14 days (5-31), P = 0.582] and postnatal LOS [DZX, 23 days (11-49) vs. WW, 22 days (8-61), P = 0.915] were comparable. Median TID was >3-fold longer in the DZX than the WW group [62.5 days (9-198) vs. 16 days (6-27), P < 0.001].

Conclusion

CLD and LOS are comparable between WW and DZX groups. Since fasting studies determine the resolution of HH, physicians should be aware that clinical intervention of DZX-treated SGA-HH patients extends beyond the initial LOS.

Diazoxide for Neonatal Hyperinsulinemic Hypoglycemia and Pulmonary Hypertension

Hypoglycemia in neonates is associated with long-term neurodevelopmental effects. Hyperinsulinemic hypoglycemia (HH) is the most common cause of persistent hypoglycemia in neonatal intensive care units. Diazoxide is the only medication that is currently recommended for treatment of HH in neonates. However, the use of diazoxide in neonates is associated with pulmonary hypertension as an adverse effect. In this article, we review the literature on the mechanism of action and adverse effects with the use of diazoxide in neonatal hyperinsulinism. We then present a case series of neonates treated with diazoxide in our neonatal intensive care unit over a 5-year period. Among 23 neonates who received diazoxide, 4 developed pulmonary hypertension and 1 died. All infants who developed pulmonary hypertension were born preterm at less than 36 weeks gestation and had pre-existing risk factors for pulmonary hypertension. HH in preterm neonates, with pre-existing pulmonary hypertension or with risk factors for pulmonary hypertension requires thoughtful management.

Oral diazoxide versus placebo for severe or recurrent neonatal hypoglycaemia: Neonatal Glucose Care Optimisation (NeoGluCO) study - a randomised controlled trial

INTRODUCTION

Infants with severe or recurrent transitional hypoglycaemia continue to have high rates of adverse neurological outcomes and new treatment approaches are needed that target the underlying pathophysiology. Diazoxide is one such treatment that acts on the pancreatic β-cell in a dose-dependent manner to decrease insulin secretion.

METHODS AND ANALYSIS

Phase IIB, double-blind, two-arm, parallel, randomised trial of diazoxide versus placebo in neonates ≥35 weeks' gestation for treatment of severe (blood glucose concentration (BGC)<1.2 mmol/L or BGC 1.2 to <2.0 mmol/L despite two doses of buccal dextrose gel and feeding in a single episode) or recurrent (≥3 episodes <2.6 mmol/L in 48 hours) transitional hypoglycaemia. Infants are loaded with diazoxide 5 mg/kg orally and then commenced on a maintenance dose of 1.5 mg/kg every 12 hours, or an equal volume of placebo. The intervention is titrated from the third maintenance dose by protocol to target BGC in the range of 2.6-5.4 mmol/L. The primary outcome is time to resolution of hypoglycaemia, defined as the first point at which the following criteria are met concurrently for ≥24 hours: no intravenous fluids, enteral bolus feeding and normoglycaemia. Groups will be compared for the primary outcome using Cox's proportional hazard regression analysis, expressed as adjusted HR with a 95% CI.

ETHICS AND DISSEMINATION

This trial has been approved by the Health and Disability Ethics Committees of New Zealand (19CEN189). Findings will be disseminated in peer-reviewed journals, to clinicians and researchers at local and international conferences and to the public.

TRIAL REGISTRATION NUMBER

ACTRN12620000129987.

Safety and efficacy of low-dose diazoxide in small-for-gestational-age infants with hyperinsulinaemic hypoglycaemia

OBJECTIVES

Diazoxide (DZX) is the drug of choice for treating hyperinsulinaemic hypoglycaemia (HH), and it has potentially serious adverse effects. We studied the safety and efficacy of low-dose DZX in small-for-gestational-age (SGA) infants with HH.

DESIGN

An observational cohort study from 1 September 2014 to 31 September 2020.

SETTING

A tertiary Women's and Children's Hospital in Singapore.

PATIENTS

All SGA infants with HH.

INTERVENTION

Diazoxide, at 3-5 mg/kg/day.

MAIN OUTCOME MEASURES

Short-term outcomes; adverse drug events and fasting studies to determine 'safe to go home' and 'resolution' of HH.

RESULTS

Among 71 836 live births, 11 493 (16%) were SGA. Fifty-six (0.5%) SGA infants with HH were identified, of which 27 (47%) with a mean gestational age of 36.4±2 weeks and birth weight of 1942±356 g required DZX treatment. Diazoxide was initiated at 3 mg/kg/day at a median age of 10 days. The mean effective dose was 4.6±2.2 mg/kg/day, with 24/27 (89%) receiving 3-5 mg/kg/day. Generalised hypertrichosis occurred in 2 (7.4%) and fluid retention in 1 (3.7%) infant. A fasting study was performed before home while on DZX in 26/27 (96%) cases. Diazoxide was discontinued at a median age of 63 days (9-198 days), and resolution of HH was confirmed in 26/27 (96%) infants on passing a fasting study.

CONCLUSION

Our study demonstrates that low-dose DZX effectively treats SGA infants with HH as measured by fasting studies. Although the safety profile was excellent, minimal adverse events were still observed with DZX, even at low doses.

Asymptomatic Hyperinsulinemic Hypoglycemia and Grade 4 Intraventricular Hemorrhage in a Late Preterm Infant

Hyperinsulinemic hypoglycemia (HH) has the potential to cause acute neurologic dysfunction and neurodevelopmental impairment. Parieto-occipital neuronal injuries have been reported in hypoglycemic infants, but intraparenchymal hemorrhage is rare. On day 5 of life, a late preterm infant was transferred to our care with recurrent asymptomatic hypoglycemia. Prior to arrival, plasma glucose levels were at a median of 1.25 mmol/L (22.5 mg/dL) in the first 6 hours of life, and he required a glucose infusion rate (GIR) of 22.6 mg/kg/min. Hyperinsulinism was confirmed in the presence of detectable insulin, low ketones, and fatty acid when hypoglycemic. A left grade 4 intraventricular hemorrhage (IVH) was noted in the cranial ultrasound scan during the workup for sepsis on the day of admission. However, magnetic resonance imaging of the brain on day 7 of life revealed extensive bilateral IVH. On day 9, he was initiated on diazoxide, and HH resolved within 48 to 72 hours, allowing increment of feeds while weaning GIR. Ventricular drain for post-hemorrhagic ventriculomegaly was advised but not performed. At 3 months, post-hemorrhagic ventriculomegaly was stable, and there were early signs of neurodevelopmental delay. After discontinuing diazoxide at 4 months of age, he passed an 8-hour fasting study confirming the resolution of HH. Severe hypoglycemia has been associated with cerebral hyperperfusion in preterm infants and potentially could cause IVH. Close monitoring and prompt intervention in preterm infants to prevent severe hypoglycemia are paramount. In addition to long-term neurodevelopmental follow-up, infants with recurrent hypoglycemia may benefit from neuroimaging and thereby early intervention if required.