Delayed presentation of prolonged hyperinsulinaemic hypoglycaemia in a preterm small-for-gestational age neonate

Area of Science:

• Neonatology
• Pediatric Endocrinology
• Medical Genetics

Background:

• Hyperinsulinemic hypoglycemia (HH) typically manifests within the first 48 hours of life in small-for-gestational age (SGA) infants.
• SGA infants are at increased risk for various metabolic complications, including hypoglycemia.

Observation:

• A preterm, SGA female infant born at 32(+6) weeks gestation presented with hyperinsulinemic hypoglycemia on postnatal day 13.
• The infant exhibited lethargy, hypoglycemia, hyperinsulinism, hypoketonaemia, and hypofattyacidaemia, requiring a high glucose infusion rate.
• Initial septic and metabolic screens were negative, and there was no immediate response to diazoxide therapy. Genetic testing for ABCC8 and KCNJ11 mutations was also negative.

Findings:

• The infant showed a delayed but eventual positive response to diazoxide, with complete resolution of hypoglycemia by 5 months of age.
• This case demonstrates a rare presentation of late-onset hyperinsulinemic hypoglycemia in a preterm SGA infant.
• Negative genetic studies for common HH mutations suggest potential alternative genetic or epigenetic factors.

Implications:

• Highlights the importance of prolonged glucose monitoring in preterm SGA infants until full feeds and weight gain are achieved.
• Underscores the need for early recognition and management of hypoglycemia to prevent adverse neurodevelopmental outcomes.
• Suggests considering diazoxide therapy even in cases with initial non-response and negative genetic testing for common HH-associated genes.