Congenital Hyperinsulinism

The human body has unique mechanisms by which it controls the blood sugar (glucose) level. All the body systems (especially the brain) are continually dependent on a normal (3.5-5.5mmol/L) circulating blood glucose level. Both high (hyperglycaemia) and low (hypoglycaemia) glucose levels can cause problems. The blood glucose level is controlled by chemicals called hormones. Insulin is one of these hormones and plays an important role in controlling the glucose level. Insulin is produced by specialised cells (called beta-cells) in the human pancreas.

Under normal conditions the beta-cells produce only the right amount of insulin in relation to the blood glucose level (to keep the blood glucose in the normal range). The blood glucose level regulates the amount of insulin the beta-cells produce. The higher the blood glucose level the more insulin will be produced and vice versa. In Congenital Hyperinsulinism (CHI) the beta-cells start producing too much and inappropriate amounts of insulin. The production of insulin becomes autonomous and is not controlled by the blood glucose level. The result of this is that there is too much insulin in the blood which lowers the blood glucose level (hypoglycaemia) to dangerous levels. The low blood glucose level is dangerous as all the body systems are dependent on a normal blood glucose level. The presence of insulin stops the body from making alternative fuels (ketone bodies) which can then be used as an alternative to glucose. The low glucose level is especially dangerous for the brain as the brain continually depends on glucose for its function. This is why these children are at an increased risk of brain damage.