The pancreas is a small organ found near the stomach that has two main roles in the body:

• Endocrine role – this means that it releases hormones into the bloodstream, in this case beta-cells release insulin (which lowers blood glucose) and alpha-cells release glucagon (which raises blood glucose by releasing it from stores).
• Exocrine role – this means that it releases enzymes via a duct into the small intestine for digestion of fats and proteins.  This shouldn’t affect hyperinsulinism patients unless they have a near-total pancreatectomy, in which case they will need to take enzyme-replacements with their meals.

In hyperinsulinism the endocrine function, specifically the beta-cells are affected.

In the focal form of the disease the affected cells are located together in a cluster.  This focus is generally spherical between 2-10mm but can be much bigger or even have an “octopus” shape.  If the focus is removed this should cure the hyperinsulinism.

In the diffuse form, all the beta cells in the pancreas are affected.  Therefore treatment aims to stop all of these cells from producing too much insulin.  This is done through medication.  If this fails then doctors may decide to remove most of the pancreas. However, this does not remove all the beta cells and the hyperinsulinism may persist.

What is Insulin and now does it work?

Alder Hey Patient Information leaflet:

Insulin is a hormone, which controls the level of glucose (sugar) in the blood. Insulin is released by specialised beta-cells in the pancreas.

As food is eaten, blood glucose rises and the pancreas releases insulin to keep the blood glucose in the normal range. Insulin acts by driving glucose into the cells of the body. This action of insulin has two effects:

1. Maintaining blood glucose levels
2. Storing glucose as glycogen in the liver During a fast, 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 way, whether one eats or is fasting blood glucose levels remain in the normal range and the body has access to energy at all times.

What goes wrong in CHI?

 In CHI, the close regulation of blood glucose and insulin secretion is lost. The pancreas, which is responsible for insulin secretion, is blind to the blood glucose level and continues to release insulin despite low blood glucose level.

As a result, the baby or child with CHI develops severe hypoglycemia and ends up needing large amounts of glucose to maintain normal blood glucose levels.