Diabetic neuropathy

Neuropathy, or nerve damage, is a common complication of diabetes.

Key points

  1. Diabetic neuropathy (nerve damage) is a range of disorders that can affect three types of nerves (sensory, motor, and autonomic).
  2. It causes pain and/or numbness. Feet are often affected.
  3. The exact cause of nerve damage is not known, but high blood glucose levels over a long period are thought to be involved.
  4. To help prevent nerve damage, experts recommend you try to maintain healthy blood glucose and blood pressure levels, not smoke and avoid excess alcohol.

The nervous system

The nervous system consists of the brain and the nerves. The central core of the nervous system is the spinal cord and brain. The nerves that are outside the brain and the spinal cord are called peripheral nerves.

There are three types of peripheral nerves:

  • sensory nerves which carry signals such as pain from the body to the brain (eg, 'ouch, I am standing on a pin!')
  • motor nerves that carry the signal back from the brain to the muscles ('move your foot quickly and get off that pin!')
  • autonomic nerves which control things like heart beat, blood pressure, and breathing, automatically (you don't need to feel these or do anything about them, they happen by themselves).

Damage to your nerves can interrupt the signals to and from the brain.

What causes nerve damage?

Researchers do not yet know precisely what causes the neuropathy that occurs in diabetes. Blood glucose levels play a role. Neuropathy is more likely to affect people who have had diabetes for a long time or whose blood glucose levels have been high over a long period of time.

But no one is sure how high glucose levels must be, and for how long, before nerve damage happens.

Neuropathy can be caused by a number of other things as well as diabetes:

  • too much alcohol over a long period of time
  • severe vitamin B deficiency or overdose
  • injury
  • some medications.

What are the symptoms of nerve damage caused by diabetes?

There are a range of different neuropathies (or forms of nerve damage) that people with diabetes can develop. Virtually all of these conditions affect the peripheral nerves.

The symptoms vary with the type of nerve fibre being affected:

  • motor – if the loss of nerve fibres affects the motor fibres, it can cause weakness in your muscles
  • sensory – if loss of nerve fibres affects the sensory fibres, it can cause loss of feeling
  • autonomic – if the loss of nerve fibres affects autonomic fibres, it can cause loss of functions not normally under conscious control, like digestion.

You may experience symptoms when your nerves are damaged, or healing. These symptoms include prickling, tingling, burning, aching, or sharp jabs of needle-like pain. These are signs of the increased nerve activity that occurs in damaged or healing nerves.

What treatment is available for nerve damage caused by diabetes?

Health professionals and researchers are still looking for a way to heal nerves damaged by neuropathy. Right now, treatment aims to make the symptoms of neuropathy better. Improving your blood glucose levels may improve early neuropathy.

Painful neuropathy can be very disabling. In fact, a lot of people with painful neuropathy can get seriously depressed. The good news is that painful neuropathy usually follows a distinct course. It starts, it goes on, and then it ends. It usually ends within several months to a year.

Medication

There are a range of medications available that can help relieve the pain of a painful neuropathy. Some of the options are:

  • non-steroidal anti-inflammatory agents (NSAIDs), eg: ibuprofen
  • tricyclic antidepressant drugs, eg: amitriptyline
  • analgesics, eg: tegretol.

Some people have found relief through using capsaicin cream or a therapy called TENS (transcutaneous electrical nerve stimulation). This therapy is often available through hospital specialists who specialise in pain management.

If you have a painful neuropathy, see a diabetes specialist as soon as possible. You may also need referral to a doctor who specialises in pain.

Learn more 

See the Health Navigator Diabetes page
Visit Diabetes NZ website

Credits: Original material provided by Diabetes New Zealand, 2008. Reviewed By: Health Navigator Team