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Hyperinsulinemic hypoglycemia is the common cause of persistent hypoglycemia in the newborn.
Mutations in the ABCC8 and KCNJ1 genes are most common and impact the function of the ATP – Potassium Channel in the Beta cell of the islet.
Medical therapy includes treatment with continuous feedings, diazoxide and somatostatin analogs.
The 2 primary manifestations of the disease are focal and diffuse.
Patients with diffuse disease failing medical therapy are treated with 95% pancreatectomy.
Patients with focal disease failing medical therapy are treated with complete enucleation of the lesion.
Minimally invasive approaches to surgery have been described.
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Hyperinsulinemic Hypoglycemia of Infancy
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Hypoglycemia is a common finding in neonates, infants, and children and is most commonly a secondary response to other systemic conditions such as sepsis, central nervous system pathology, congenital heart disease, drug effects, and asphyxia or anoxia. Most of these episodes are transient and very few patients require evaluation for persistent or intermittent hypoglycemia. In approximately 1% to 2% of all newborns with hypoglycemia, low serum glucose levels persist despite high rates of infusion of intravenous glucose. Within this very small subgroup, one must consider several possible etiologies including metabolic disease due to inborn errors of metabolism, hormonal deficiencies related to pituitary aplasia or hypoplasia, and persistent hyperinsulinemic hypoglycemia of infancy (HHI).
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Despite its rarity, HHI is the most common cause of persistent hypoglycemia in the newborn. The incidence is reported to be 1:50,000 in the general population although it can be significantly more common in some in-bred populations. Gray and Feemster first described the condition in 1924 and in 1938 Laidlaw coined the term nesidioblastosis to describe the histologic findings of an overabundance of islets in the pancreas. Since then a number of different histologic manifestations of beta-cell abnormalities have been described and over the past 2 decades we have gained a more complete understanding of the underlying genetic and molecular processes that characterize the various subtypes of the disease. This chapter will outline our current understanding of the disease variants and the medical and surgical approaches to treatment.
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Dysregulation of beta-cell production and release of insulin is the primary abnormality resulting in persistent hypoglycemia. The current understanding of the basis for the dysregulation began with the cloning of the sulfonylurea receptor gene, SUR1, in 1995. SUR1 is closely linked functionally to a potassium channel (Kir6.2) and the genes for both SUR1 and Kir6.2 are in close proximity on chromosome 11. Mutations in the ATP-regulated potassium channel alter the calcium dependent release of insulin from storage granules in the beta-cell resulting in various forms of the disease.
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Beta-cell dysfunction can be diffused throughout the pancreas or can be present as a focal lesion related to clonal expansion of a single beta-cell defect. In large series, diffuse disease is far more common and accounts for about ...