Important It is possible that the main title of the report Congenital Hyperinsulinism is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
islet cell dysregulation syndrome
persistent hyperinsulinemic hypoglycemia of infancy (PHHI)
exercise induced HI
GDH HI or HI/HA
focal KATP HI
diffuse KATP HI
Congenital hyperinsulinism (HI) is the most frequent cause of severe, persistent hypoglycemia in newborn babies and children. In most countries it occurs in approximately 1/25,000 to 1/50,000 births. About 60% of babies with HI are diagnosed during the first month of life. An additional 30% will be diagnosed later in the first year and the remainder after that. With early treatment and aggressive prevention of hypoglycemia, brain damage can be prevented. However, brain damage can occur in children with HI if the condition is not recognized or if treatment is ineffective in the prevention of hypoglycemia.
Insulin is the most important hormone for controlling the concentration of glucose in the blood. As food is eaten, blood glucose rises and the pancreas secretes insulin to keep blood glucose in the normal range. Insulin acts by driving glucose into the cells of the body. This action of insulin maintains blood glucose levels and stores glucose as glycogen in the liver. Once feeding is completed and glucose levels fall, insulin secretion is turned off, allowing the stores of glucose in glycogen to be released into the bloodstream to keep blood glucose normal. In addition, with the switching off of insulin secretion, protein and fat stores become accessible and can be used instead of glucose as sources of fuel. In this manner, whether one eats or is fasting blood glucose levels remain in the normal range and the body has access to energy at all times.
This close regulation of blood glucose and insulin secretion does not occur normally in people who have HI. The beta cells in the pancreas, which are responsible for insulin secretion, are blind to the blood glucose level and secrete insulin regardless of the blood glucose concentration. As a result, the baby or child with HI can develop hypoglycemia at any time but particularly when fasting. In the most severe form of HI this glucose blindness causes frequent, random episodes of hypoglycemia.
HI causes a particularly damaging form of hypoglycemia because it denies the brain of all the fuels on which it is critically dependent. These fuels are glucose, ketones, and lactate. The usual protective measures against hypoglycemia, such as conversion of protein to glucose (called gluconeogenesis) and conversion of fat into ketones (called fatty acid oxidation and ketogenesis) are prevented by insulin. Once the brain cells are deprived of these important fuels, they cannot make the energy they need to work and so they stop working. The lack of appropriate fuel to the brain may result in seizures and coma and if prolonged may result in death of the cells. It is this cell damage which can manifest as a permanent seizure disorder, learning disabilities, cerebral palsy, blindness or even death.
This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".
The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.
It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report
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Last Updated: 1/25/2013 Copyright 2013 National Organization for Rare Disorders, Inc.
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