Diabetic neuropathy (nerve damage)

Neuropathy (or nerve damage) is a common complication of diabetes.

Key points about diabetic neuropathy

  1. Diabetic neuropathy (nerve damage) can affect 3 types of nerves: sensory, motor and autonomic.
  2. It usually causes pain and/or numbness.
  3. Your feet are often affected.
  4. The exact cause of nerve damage is not known, but it is linked to high blood glucose (sugar) levels over a long period.
  5. To help prevent nerve damage, try to keep your blood glucose and blood pressure at your target levels, don't smoke and don't drink too much alcohol.

What are nerves?

Your nerves are a key part of your nervous system, which sends signals between different parts of your body. It has 2 parts: the central nervous system and the peripheral nervous system.  

Your central nervous system is made up of your brain and spinal cord. The peripheral nervous system is made up of the nerves outside of your brain and spinal cord. These are called peripheral nerves. They are long fibres that connect your brain and spinal cord to the rest of your body.

There are 3 types of peripheral nerves:

  • sensory nerves – these carry signals such as pain from your body to your brain, eg, 'ouch, I am standing on a pin!'
  • motor nerves – these carry the signal back from your brain to your muscles, eg, 'move your foot quickly and get off that pin!'
  • autonomic nerves – these automatically control things like your heart beat, blood pressure and breathing, which means they happen by themselves without you needing to feel or do anything about them.

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

What causes nerve damage?

It is not yet known exactly what causes the nerve damage that occurs in diabetes. However, 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 we don't know 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:

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

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. Nearly all these conditions affect your peripheral nerves.

The symptoms are different depending on which nerve type is 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 when they are 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.

Look after your feet

If you have diabetes and nerve damage in your feet, you are at much higher risk of getting a foot infection or foot ulcer, which can be very serious. Make sure you look after your feet carefully and see your doctor as soon as possible if you notice any foot problems. Read more about how to take care of your feet when you have diabetes

What treatment is available for nerve damage caused by diabetes?

Treatment aims to reduce symptoms of neuropathy and make life more comfortable, as there is no way to cure neuropathy yet. Improving your blood glucose levels may improve early neuropathy and reduce the chances of it getting worse.

Painful neuropathy can be very difficult to live with and you may be at risk of depression. Talk to your GP if this is the case for you.

The good news is that painful neuropathy usually follows a clear pattern: it starts, it goes on and then it ends, usually within a few months to a year.

Self-care

People with long term pain often find it easier to live with their condition if they make a management plan with their healthcare provider that includes the following:

  • trying to improve sleep
  • healthy eating
  • keeping up regular activity – physical and social, doing things you enjoy
  • planning your daily activities to avoid too much tiredness
  • talking to other people about how you are feeling – friends, family/whānau or support groups

Support is also available by referral to specialist professionals such as physiotherapists, occupational therapists or counsellors/psychologists. 

Read more here about long term (chronic) pain.

Medicine

There are a range of medicines that may help relieve neuropathy pain. Many of them were originally designed for another medical condition but over the years have been found also to work for nerve pain.

Some of the options are:

Some people have found pain relief from 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 

Nerve damage Diabetes NZ

Reviewed by

Dr Alice Miller trained as a GP in the UK and has been working in New Zealand since 2013. She has undertaken extra study in diabetes, sexual and reproductive healthcare, and skin cancer medicine. She is looking forward to further study with Otago University in public health to learn about how we can reduce preventable disease and inequalities.
Credits: Health Navigator Editorial Team. Reviewed By: Dr Alice Miller, FRNZCGP, Wellington Last reviewed: 19 Apr 2021