P3C247: Neonatal Graves Disease with Transient Stress-induced Hyperinsulinism: A Case Report

Introduction: Neonatal Graves disease is the most common cause of hyperthyroidism during the newborn period. Hyperthyroidism commonly leads to hyperglycemia due to increased endogenous release of glucose. Hypoglycemia is the most common endocrinological disorder during the newborn period but most hypoglycemic episodes resolve within 24-48 hours after birth. Maternal Graves disease increases risk of intrauterine growth restriction (IUGR), small for gestational age (SGA) and neonatal Graves disease. IUGR and SGA are associated with transient hyperinsulinism. Neonatal Graves disease with transient hyperinsulinism and severe hypoglycemia has not been described.

Case Description: We present the case of a female patient born at 34 weeks and 3 days at 1.6 kg (5th percentile) to a mother with recent treatment for Graves disease. The mother did not begin hyperthyroidism medical therapy until 23 weeks and 2 days of gestation, when she presented to the emergency room with thyrotoxicosis. After the infant was born, the infant not only had symptoms of hyperthyroidism such as tachycardia and abnormal thyroid values, but also she had persistent hypoglycemia secondary to transient stress-induced hyperinsulinism. The infant was started on methimazole and propranolol for hyperthyroidism and subsequent tachycardia. She was started on diazoxide for persistent hypoglycemia. After discharge and by 6 months of age, the hyperthyroidism and transient hyperinsulinism had resolved.

Discussion: The transient stress-induced hyperinsulinism was likely due to multifactorial causes such as intrauterine growth restriction and the perinatal stress of delayed treatment of maternal Graves disease. This is the first documented case of neonatal Graves disease with severe persistent hypoglycemia due to stress-induced hyperinsulinism.

Conclusion: Pediatricians, endocrinologists, neonatologists, & OB/Gyns need to be aware of transient hyperinsulinism as a potential risk with IUGR and SGA, especially in the setting of maternal Graves disease and neonatal hyperthyroidism. It is important to diagnose neonatal Graves and stress induced hyperinsulinism early so that life threatening symptoms, such as tachycardia, heart failure, and in this case, hypoglycemia, can be immediately treated and managed long term.