Management strategy for congenital hyperinsulinism with atrial septal defect and diazoxide-induced pulmonary hypertension

Congenital hyperinsulinism (CHI) is characterized by hypoglycemia caused by excessive insulin secretion. CHI is classified into two types: transient CHI, which resolves within 3-4 mo of birth, and persistent CHI, which persists beyond this period. Diazoxide, the first-line treatment for CHI, may cause pulmonary hypertension (PH) as a side effect. Here, we report the case of a 2-mo-old girl with CHI and an atrial septal defect who initially responded well to diazoxide but developed dose-dependent PH. Diazoxide was discontinued, and treatment was switched to octreotide, glycogen storage disease milk, and glucagon. However, maintaining stable blood glucose levels remained challenging. Surgical intervention is typically required when medical management is ineffective; however, such procedures are limited to specialized facilities. Additionally, pancreatic resection carries a high risk of postoperative diabetes. To enable the safe reintroduction of diazoxide, we surgically closed the atrial septal defect with a left-to-right shunt and combined diazoxide therapy with anti-PH medication. This approach successfully controlled PH and achieved good glycemic control.