Diabetic neuropathy

Diabetic neuropathy is a term, which is used to cover a number of manifestations of nerve disease in diabetes.

Once again it is useful to know the abnormal physiology behind nerve damage so that we can understand the processes and principles of prevention and treatment. If you need a reminder have a look at the A&P of the nerves of the body- we are most interested in the effect of diabetes in the peripheral nervous system.

Current evidence shows that the main reason why nerve damage occurs is the essential feature of hyperglycaemia, which leads to decreased nerve function and synapse transmission.

Have a look at this animation, which demonstrates nerve anatomy and normal nerve function. It also indicates the main nerve components which current research identifies as being abnormally affected by hyperglycaemia.

Explanation of Animation

The animation shows a representation of the nervous system. Then the animation demonstrates the detailed structure of a nerve fibre. Possible sites of nerve damage are indicated for blood vessels, connective tissue, schwann cells and axons.

Although we know that nerve damage is caused by a number of factors, scientists are still as yet unclear as to the precise patho-physiological mechanism. Research is currently being carried out into damage to the blood supply to nerves ( this is similar to the capilliary damage you have already studied in relation to retinopathy); the neuro peptide involvement; the sorbitol nerve induction pathway and affects on myelin substances.

The sorbitol pathway theory involves the swelling of the Swann cells which form the sheath of the nerves, which is caused by increased levels of sorbitol which in turn has been caused by the increased levels of blood glucose.

This process leads to two main types of diabetic neuropathy which are classified as progressive, non-reversible- symmetrical sensory neuropathy and autonomic neuropathy.