Endocrine Abstracts

Introduction: Congenital hyperinsulinism (CHI) typically presents in the neonate, however a minority of cases (~ 35%) present later in infancy and childhood. We report the challenging case of an older infant presenting with hypoglycaemia, diagnosed with CHI and managed entirely within a secondary care setting.

Case report: A 9-month-old macrosomic (99th centile) infant presented to the Children’s Emergency Department with hypoglycaemia and a 1 week history of seizure-like episodes. Parents reported a voracious appetite, and distress with delayed feeds, but no significant medical background. Hypoglycaemia was confirmed and initially two incomplete hypoglycaemia screens were performed. Prompt central venous access enabled controlled induction of hypoglycaemia (2.6 mmol/l) allowing a full panel of investigations, with the safety of prompt treatment with secure intravenous access. Although intravenous glucose requirements were 6–7 mg/kg per min, which is borderline for CHI, the results (glucose 2.6 mmol/l, insulin 51 pmol/l and β-hydroxybutyrate 0.1 mmol/l) confirmed CHI. Other endocrine and metabolic investigations were normal. Genetics for ABCC8/KCNJ11 were negative. Results are awaited for other genes responsible for CHI and Beckwith–Wiedemann. The patient responded to diazoxide at a dose of 5 mg/kg per day. He was discharged with regular follow-up, including long-term neuro-developmental assessment due to the week-long delay in presentation.

Conclusion: Following this case, a local non-diabetic hypoglycaemia guideline (including a ‘hypo screen’ pack containing the relevant blood bottles) was developed, advising clinicians of the differentials, essential investigations and initial management, and indications for urgent central access. This case highlights the diagnostic challenges of an uncommon presentation of CHI in later infancy to secondary care. The safe diagnosis (controlled induction of hypoglycaemia), and management exclusively in secondary care, was permitted by the expertise of a paediatrician with a special interest in hypoglycaemia, and local facilities to place secure central venous access, avoiding untreatable hypoglycaemia with long term neuro-developmental sequelae.