Beyond BRUE (Brief Resolved Unexplained Event): Recurrent Unexplained Events Revealing Congenital Hyperinsulinism in Infancy.

Brief resolved unexplained events (BRUEs) are uncommon yet clinically significant presentations in infancy that require careful risk stratification, as recurrent episodes may herald serious occult pathology. We report a four-month-old term female infant with a notable family history of sudden unexplained sibling deaths who was admitted to and later discharged from our institution twice for recurrent BRUE episodes following an initially unrevealing workup. She subsequently presented again with vomiting, diarrhea, dehydration, metabolic acidosis, and persistent hypoglycemia, necessitating admission to the pediatric intensive care unit (PICU).  During PICU admission, the infant developed recurrent hypoglycemia despite escalating intravenous glucose infusion rates (GIRs). Critical sampling demonstrated inappropriately detectable insulin and C-peptide, absent ketonuria, suppressed β-hydroxybutyrate, and a diagnostically significant glycemic response to glucagon, confirming hyperinsulinemic hypoglycemia (HH) consistent with congenital hyperinsulinism (CHI). She responded promptly to diazoxide and hydrochlorothiazide, allowing successful weaning from intravenous glucose and transition to full oral feeds. This case compellingly demonstrates how seemingly benign recurrent BRUE episodes may, in fact, constitute the earliest clinical clue to a serious yet treatable occult disorder.