Two threats in early life: congenital hyperinsulinemic hypoglycemia and thrombosis.

Background: Congenital persistent hyperinsulinemic hypoglycemia (HH) is a rare disorder that can lead to severe and recurrent hypoglycemic episodes in neonates and infants. Management often requires intensive glucose infusion via central venous catheters (CVCs), which may increase the risk of thrombosis. While case reports suggest thrombosis can occur in HH, the incidence, risk factors, severity, and outcomes remain poorly understood. Objectives: This study aimed to determine the incidence of thrombosis in children with persistent HH and to evaluate potential risk factors associated with thrombotic complications. Design: A descriptive, retrospective cohort study of patients with persistent HH followed at a university pediatric endocrinology clinic between January 2000 and December 2025. Methods: Twenty patients with persistent HH were included. Data on demographics, clinical characteristics, laboratory results, treatment protocols, CVC use, timing and location of thrombosis were collected. Patients who developed thrombosis were compared with those who did not to identify risk factors. Results: Among 20 patients, 55% were male, with a median age at diagnosis of 1 day. A total of 23 CVCs were placed in 15 patients, with a median dwell time of 38 days. Thrombosis occurred in nine patients (45%), including six catheter-related and three catheter-independent intracranial thrombosis. Median age at thrombosis detection was 74 days. Patients who developed thrombosis experienced significantly more hypoglycemic episodes and more days with hypoglycemia ( Conclusion: Thrombosis is a frequent and clinically significant complication in persistent HH. Recurrent and severe hypoglycemic episodes are major risk factors. Routine thrombosis screening, particularly in patients with CVCs, may allow early detection and treatment even in asymptomatic cases.