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Plasma proinsulin and C-peptide concentrations in children with hyperinsulinaemic hypoglycaemia
Insights
Elevated proinsulin and C-peptide levels are common in children with severe hypoglycemia and high insulin. However, these markers do not reliably indicate the specific pancreatic cause of the condition.
Area of Science:
- Pediatric Endocrinology
- Metabolic Disorders
- Pancreatic Pathophysiology
Background:
- Severe hypoglycemia in children can be linked to elevated insulin levels.
- Understanding the role of pancreatic B-cell products is crucial for diagnosing the cause of hypoglycemia.
Purpose of the Study:
- To investigate plasma proinsulin and C-peptide levels in children with hypoglycemia and elevated immunoreactive insulin (IRI).
- To determine if these B-cell product profiles correlate with specific pancreatic abnormalities.
Main Methods:
- Measurement of plasma proinsulin and C-peptide concentrations in five children with severe hypoglycemia and elevated IRI.
- Comparison of results with 13 normal infants.
- Analysis of pancreatic tissue in four children who underwent pancreatectomy.
Main Results:
- All children exhibited markedly elevated plasma proinsulin concentrations.
- Highest proinsulin levels were observed in cases of isolated adenoma and nesidioblastosis with microadenoma.
- Elevated C-peptide concentrations were noted, though their levels varied and were sometimes inappropriately high during hypoglycemia.
Conclusions:
- Elevated proinsulin and C-peptide are consistently found in children with hypoglycemia and increased IRI.
- The specific profile of proinsulin and C-peptide concentrations is not a reliable diagnostic marker for the underlying pancreatic abnormality in these cases.
Abstract:
Plasma concentrations of proinsulin and C-peptide were measured in five children presenting with severe hypoglycaemia associated with elevated plasma levels of immunoreactive insulin (IRI) in order to determine whether the profile of circulating B-cell products related to the underlying pathophysiology of the pancreas. Results were compared with data from 13 normal infants. Four children, three neonates and a nine year old girl, were subjected to partial or total pancreatectomy. The neonates had nesidioblastosis, nesidioblastosis with a microadenoma, and a functional abnormality without histological derangement respectively; the older child had a localised adenoma. The remaining child, a neonate, had transient hypoglycaemia and elevated IRI levels associated with hyperlactataemia and hyperalaninaemia. All the children had markedly elevated plasma proinsulin concentrations; the highest levels were seen in the child with an isolated adenoma and in the neonate with nesidioblastosis and a microadenoma. Both of these children also had substantially elevated plasma C-peptide concentrations. The remaining three neonates had plasma C-peptide levels, which although in the normal range for normoglycaemia were inappropriately elevated during hypoglycaemia. It is concluded that elevated proinsulin and C-peptide concentrations are seen in children with hypoglycaemia associated with increased plasma IRI levels and that the profile of the concentrations does not provide a reliable marker for the nature of the underlying pancreatic abnormality.