In hyperinsulinism (thesaurus synonyms: Beta-cell hyperplasia of the islets of Langerhans; beta-cell hyperplasia; B-cell hyperplasia; ectopic hyperinsulinism; encephalopathy due to hyperinsulinism; encephalopathy due to hypoglycemic coma; functional hypoglycemia, without increase in insulin levels; functional hyperinsulinism; glucopenia; hyperinsulinemia; hyperinsulinism; infantile hypoglycemia; nondrug-induced reactive hypoglycemia; posthypoglycemic encephalopathy; postoperative hypoglycemia; ICD-10-GM E16. 1: Other hypoglycemia) is the presence of elevated insulin levels in the blood (fasting insulin > 17 mU/l). Hyperinsulinism may be caused by increased secretion of insulin by the pancreas or by a disturbance in the breakdown of insulin. The former may be due to peripheral insulin resistance (e.g., in the presence of metabolic syndrome or type 2 diabetes mellitus). Tumors (insulinomas, rare mostly benign tumors) can also lead to an overproduction of insulin.
A distinction is made between acquired hyperinsulinism and congenital hyperinsulinism. In this case, insulin secretion by the beta cells of the pancreas is pathologically (abnormally) increased.
Congenital hyperinsulinism can be divided into the following forms:
- Focal congenital hyperinsulinism – secretion is impaired in a limited tissue area.
- Global congenital hyperinsulinism – secretion is globally, diffusely disturbed.
- Atypical congenital hyperinsulinism – assignment from the first two forms is not possible.
Frequency peak: hyperinsulinism can occur at any age, either temporary (intermittent) or persistent. Congenital hyperinsulinism manifests immediately after birth or within the first year of life.
The incidence (frequency of new cases) of congenital hyperinsulinism is estimated to be approximately 1 case per 40,000 population per year (in Northern Europe).
Course and prognosis: Hyperinsulinism leads to hypoglycemia (low blood sugar) if left untreated. Without counter-regulation (i.e., intake of monosaccharides/simple carbohydrates, usually glucose (dextrose)), hypoglycemic coma (hypoglycemia with severe loss of consciousness) may result. Therapy for hyperinsulinism depends on the underlying disease.
