Conjugated hyperbilirubinemia among infants with hyperinsulinemic hypoglycemia.

From clinical practice, we noted that a subset of neonates with hyperinsulinism develop conjugated hyperbilirubinemia. A relationship between these two conditions has not been previously described. We aimed to assess the incidence of cholestasis in a cohort of neonates with hyperinsulinism and describe their clinical characteristics. In a retrospective cohort of 63 neonates with hyperinsulinism, 48% developed cholestasis (conjugated bilirubin > 17 μmol/L) with a median maximum conjugated bilirubin of 81 [21 to 191] μmol/L. A history of fetal distress (RR 2.3 [1.24-4.45], p < 0.01) and prematurity (RR 2.0 [1.23-3.26], p <0.01) was associated with the development of cholestasis, but not parental nutrition or other pharmacological treatments. An underlying etiology for the cholestasis was only found in 1 patient, and in all cases the cholestasis spontaneously improved.Conclusions: A significant percentage of infants with hyperinsulinism develop idiopathic, spontaneously resolving, conjugated hyperbilirubinemia. The association with a history of fetal distress potentially suggests that intrauterine factors leading to hyperinsulinism may also predispose towards conjugated hyperbilirubinemia. While the presence of neonatal cholestatic jaundice warrants timely investigations to exclude important underling etiologies, if validated, these findings may support a less invasive diagnostic workup of conjugated hyperbilirubinemia in infants with co-existent hyperinsulinism. What is Known: • Hyperinsulinism and conjugated hyperbilirubinemia are two common presentations in neonates. • A clinical association between the two conditions has not been described. What is New: • A significant proportion of infants with hyperinsulinism develop idiopathic, spontaneously resolving conjugated hyperbilirubinemia. • Increased risk for cholestasis in this patient population is associated with fetal distress and prematurity but not parental nutrition.