Diabetic neuropathy is long-term damage to the nerve fibres.
It happens when high blood glucose levels are present over several years.
In diabetes, the form it usually first takes is reduced sensation in the feet.
The nerve damage affects each foot equally and eventually spreads up the legs.
Poor sensation in your feet makes them more prone to injury. Combined with poor circulation this can easily lead to ulcers and infections.
The nerve damage can be short term (acute) or long term (chronic).
Neuropathy is a common name for complications affecting the nervous system.
- Acute neuropathy (neuritis) usually disappears once the diabetes is under control. It often presents as a burning sensation in the feet and is especially bad at night and can interrupt sleep.
- Chronic neuropathy has more serious implications.
Because this complication is caused by poor blood sugar control, people who don't take enough care in controlling their diabetes stand a higher risk of developing nerve damage.
How does it affect the nervous system?
An early sign of diabetic neuropathy is a lack of ability to feel vibrations, for example from a tuning fork. This test can be carried out during your annual diabetes check-up.
The same sort of nerve damage can occur in the hands. This is uncommon, and is always accompanied by problems in the feet and legs.
Unfortunately, this type of nerve damage is permanent. Once it's happened, it isn't improved by better control of diabetes.
Other types of nerve damage seen in diabetes include paralysis involving single nerves and some painful types of neuralgia (nerve pain). These nerve conditions can be improved by good diabetes control.
Damage to the autonomic nervous system
The autonomic nervous system works in the background and controls things such as blood pressure, temperature, breathing, pulse rate and the digestive system, as well as erectile function in men.
The fibres of the autonomic system reach every part of the body and are connected to the brain and spinal cord.
Long-term diabetes can damage these nerve fibres and cause many consequences, depending on which body system is involved:
- in the digestive system it can cause diarrhoea, which is usually intermittent and can be controlled with medicines to slow the bowels. It can also cause damage to the stomach nerves, leading to fullness after meals – sometimes with nausea and vomiting.
- it can cause the loss of the normal reflexes that increase our blood pressure when we stand up. This can result in dizziness on standing, sometimes enough to cause fainting.
- it can cause erectile dysfunction (ED or impotence). An erection is a complex process that involves many steps from the brain to the penis and its blood supply via the spinal cord and nerves – all of which can be affected in diabetes.
How is diabetic neuropathy treated?
The mainstays of treatment are controlling the blood sugar level and checking your feet daily to prevent foot sores developing. A podiatrist can advise you on good foot care.
The pain associated with touch can be controlled by a number of different treatments.
- Mild painkillers, such as paracetamol (Panadol) or aspirin (eg Disprin).
- Antidepressant drugs such as amitriptyline may improve the pain.
- Gabapentin (eg Neurontin), pregabalin (eg Lyrica) and duloxetine (eg Cymbalta) are licensed for nerve pain.
- Opioid painkillers, such as tramadol (eg Zydol) or dextropropoxyphene. They may be useful if other treatments have failed.
- Capsaicin cream (Zacin) applied to the feet may relieve discomfort.
- An electrical stimulator (TENS machine) provided by hospital pain clinics can help in more severe cases.
Compression stockings may help treat dizziness from standing up too quickly.
Nausea and vomiting can be treated with anti-emetics. Codeine phosphate or other antidiarrhoeal medicines may also be tried.
Ways to help yourself
- Keep blood sugar levels as normal as possible.
- Inspect your feet regularly by a qualified podiatrist.
- Have an annual foot inspection.
- See a chiropodist when necessary.
- Buy well-fitting shoes.
- Take special care when cutting toenails.
- See your GP if you have any infections, blisters or cuts that are slow to heal.
- The best way to prevent diabetic neuropathy is to keep the blood sugar level as near normal as possible.
- Neuropathy is most common in the feet, so inspect them regularly. The poor sensation it causes can mean minor injuries to your feet - and sometimes major ones - go unnoticed.
- As well as your regular checking, an annual foot inspection should be a routine part of your care by the diabetes team. It should also include access to a chiropodist if necessary.
- Well-fitting shoes are a must.
- If you do have poor sensation, you need to take special care to avoid injury, including when cutting toenails.
- Any cuts, blisters or infections that are slow to heal should be checked by your diabetes nurse or doctor.
In the long term
Acute neuropathy is less common and usually goes away in a matter of weeks or months after the blood sugar level has been normalised.
Chronic neuropathy does not disappear, but can be kept under control by good management of blood sugar levels and regular foot checks by a chiropodist.
Based on a text by Dr Jan Erik Henriksen, Dr Ole Hother Nielsen, Professor Henning Beck-Nielsen
Last updated 15.09.2008