What is Diabetes Mellitus?

Diabetes was first described over 2000 years ago. The word 'diabetes' is derived from a Greek word signifying a siphon reflecting the major symptoms - increased urine production (polyuria) and increased thirst (polydipsia). The word 'mellitus' is derived from a Greek word meaning sweet reflecting the high amounts of sugar found in the urine.

The pathological basis of the disease is due to an inadequate insulin effect either due to an insufficient release or due to a resistance to its actions. The loss of the insulin effect results in impaired glucose utilisation (due to insulin dependent glucose transport) and therefore allows the blood glucose concentration to rise. Untreated diabetes can have very severe consequences and lethal complications such as ketoacidosis and hyperosmolar coma can result.

There are two main types of diabetes mellitus which are known as Type I (also known as insulin dependent diabetes mellitus and juvenile onset) and Type II (also known as late onset and non-insulin dependent). Another type of diabetes is gestational diabetes which occurs in pregnancy in about 5% of women with an increased risk of subsequently developing Type II diabetes. A table to compare the main two types of Diabetes is shown below:

The aim of the treatment of diabetes is to replace the insulin. A common complication of treating diabetes with insulin is hypoglycaemia (low blood sugar). Even under tight blood glucose control, the patient is predisposed to heart disease, renal failure, nerve damage (neuropathy) and eye problems (retinopathy). The key to the treatment of diabetes is to minimise these problems.