Congenital hyperinsulinism is a
rare disease, but is the most frequent cause of persistent and severe hypoglycaemia in early childhood. Hypoglycaemia caused by excessive and dysregulated insulin secretion (
hyperinsulinism) from disordered pancreatic β cells can often lead to irreversible brain damage with lifelong neurodisability. Although
congenital hyperinsulinism has a genetic cause in a significant proportion (40%) of children, often being the result of mutations in the genes encoding the
KATP channel (ABCC8 and KCNJ11), not all children have severe and persistent forms of the disease. In approximately half of those without a genetic mutation,
hyperinsulinism may resolve, although timescales are unpredictable. From a histopathology perspective,
congenital hyperinsulinism is broadly grouped into diffuse and focal forms, with surgical lesionectomy being the preferred choice of treatment in the latter. In contrast, in diffuse
congenital hyperinsulinism, medical treatment is the best option if
conservative management is safe and effective. In such cases, children receiving treatment with drugs, such as
diazoxide and
octreotide, should be monitored for side effects and for signs of reduction in disease severity. If hypoglycaemia is not safely managed by medical
therapy, subtotal
pancreatectomy may be required; however, persistent hypoglycaemia may continue after surgery and diabetes is an inevitable consequence in later life. It is important to recognize the negative cognitive impact of early-life hypoglycaemia which affects half of all children with
congenital hyperinsulinism. Treatment options should be individualized to the child/young person with
congenital hyperinsulinism, with full discussion regarding efficacy, side effects, outcomes and later life impact.