Endocrine Abstracts

Introduction: Congenital hyperinsulinism (CHI) is a rare genetic disorder that is characterised by persistent hypoglycaemia in infants and children. We are reporting a rare case of diffuse CHI who was also found to have hypopituitarism and several other congenital anomalies. A similar association has not been reported in literature.

Case: A female baby was born at 42 weeks gestation with a birth weight of 4.185 kg (1.72 SDS). She suffered shoulder dystocia and was ventilated for 12 days. Her persistent hypotension, hyponatraemia, and hypoglycaemia triggered further investigations. She was noted to have low free T₄ (5.3 pmol/l), undetectable TSH (<0.03 mU/l), and plasma cortisol (<50 nmol/l). She was commenced on levothyroxine and hydrocortisone. Her glucose requirement remained high at 20 mg/kg per min and the hypoglycaemia screen revealed raised insulin (90 pmol/l) and suppressed free fatty acids and ketones during hypoglycaemia confirming CHI. The hypoglycaemia was initially managed with high concentration dextrose infusion and i.v. glucagon. She was subsequently started on diazoxide but developed cardiac failure; therefore it was replaced by s.c. octreotide injections. This was later discontinued due to liver dysfunction. Genetic analysis was negative for ABCC8, KCNJ11, and HNF4A mutations and microarray was normal. She was also noted to have pulmonary stenosis requiring balloon dilatation, unilateral choroidal coloboma, and facial dysmorphic features including single median incisor. MRI brain showed hypoplastic anterior pituitary gland with absent posterior pituitary and the ¹⁸F-DOPA PET–CT scan showed a diffuse pancreatic lesion. She is now 3-year-old and manages with continuous gastrojejunostomy feeds, hydrocortisone, levothyroxine, and GH.

Conclusion: We report a rare association of diffuse persistent CHI and hypopituitarism in a patient with several other associated anomalies with probably an unidentified genetic aetiology. The described case highlights the importance of maintaining a high degree of suspicion for alternative diagnoses in infants diagnosed with hypopituitarism but have persistent hypoglycaemia.