Peripheral neuropathy develops when nerves in the body's extremities – such as the hands, feet and arms – are damaged. The symptoms depend on which nerves are affected.
In the UK, it's estimated that almost 1 in 10 people aged 55 or over are affected by some degree of peripheral neuropathy.
The peripheral nervous system is the network of nerves that lie outside the central nervous system (the brain and spinal cord).
It includes different types of nerves with their own specific functions, including:
The main symptoms can include:
These symptoms are usually constant, but may come and go.
It's recommended that people at highest risk of peripheral neuropathy, such as people with diabetes, have regular check-ups.
Your GP will ask about your symptoms and may arrange some tests to help identify the underlying cause. You may be referred to a hospital to see a neurologist (a specialist in conditions affecting the nervous system).
Generally, the sooner peripheral neuropathy is diagnosed, the better the chance of limiting the damage and preventing further complications.
In the UK, diabetes (both type 1 and type 2) is the most common cause of peripheral neuropathy.
Over time, the high blood sugar levels associated with diabetes can damage the nerves. This type of nerve damage is known as diabetic polyneuropathy.
Peripheral neuropathy can also have a wide range of other causes. For example, it can be caused by:
People who are known to be at an increased risk of peripheral neuropathy may have regular check-ups so their nerve function can be assessed.
Treatment for peripheral neuropathy depends on the symptoms and underlying cause.
Only some of the underlying causes of neuropathy can be treated. For example, if you have diabetes it may help to gain better control of your blood sugar level, stop smoking, and cut down on alcohol.
Nerve pain may be treated with prescribed medications called neuropathic pain agents, as standard painkillers are often ineffective.
If you have other symptoms, these may need to be treated individually. For example, treatment for muscle weakness may involve physiotherapy and the use of walking aids.
The outlook for peripheral neuropathy varies, depending on the underlying cause and which nerves have been damaged.
Some cases may improve with time if the underlying cause is treated, whereas in some people the damage may be permanent or may get gradually worse with time.
If the underlying cause of peripheral neuropathy isn't treated, you may be at risk of developing potentially serious complications, such as a foot ulcer that becomes infected. This can lead to gangrene (tissue death) if untreated, and in severe cases may mean the affected foot has to be amputated.
Peripheral neuropathy may affect the nerves controlling the automatic functions of the heart and circulation system (cardiovascular autonomic neuropathy). You may need treatment to increase your blood pressure or, in rare cases, a pacemaker.
Symptoms vary according to the type of peripheral neuropathy and may develop quickly or slowly.
The main types of peripheral neuropathy include:
In many cases, someone with peripheral neuropathy may have more than one of these types at the same time.
A combination of sensory and motor neuropathy is particularly common (sensorimotor polyneuropathy).
The symptoms of the main types of peripheral neuropathy are described below.
Symptoms of sensory neuropathy can include:
Symptoms of motor neuropathy can include:
Damage to the autonomic nerves can result in a wide range of symptoms depending on where in the body the damage occurs.
Symptoms of autonomic neuropathy can include:
Depending on the specific nerve affected, symptoms of mononeuropathy can include:
The most common type of mononeuropathy is carpal tunnel syndrome (CTS). The carpal tunnel is a small tunnel in your wrist.
In CTS, the median nerve becomes compressed where it passes through this tunnel, which may cause tingling, pain or numbness in the fingers.
Diabetes is the most common cause of peripheral neuropathy in the UK.
Neuropathy can also be caused by other health conditions and certain medications. In some cases, no cause can be identified and this is termed idiopathic neuropathy.
Peripheral neuropathy caused by either type 1 diabetes or type 2 diabetes is called diabetic polyneuropathy. It's probably caused by high levels of glucose in your blood damaging the tiny blood vessels that supply your nerves.
Peripheral neuropathy becomes more likely the longer you've had diabetes. Up to 1 in every 4 people with the condition experience some pain caused by nerve damage.
If you have diabetes, your risk of polyneuropathy is higher if your blood sugar is poorly controlled or you:
If you have diabetes, you should examine your own feet regularly to check for ulcers (open wounds or sores) or chilblains.
As well as diabetes, there are many other possible causes of peripheral neuropathy.
Some of the health conditions that can cause peripheral neuropathy include:
A few medications may sometimes cause peripheral neuropathy as a side effect in some people. These include:
A number of tests may be used to diagnose peripheral neuropathy and its underlying cause.
When you see your GP, they'll ask about your symptoms and examine the affected area of your body. This may involve testing sensation, strength and reflexes.
Your doctor may also arrange blood tests, especially to check for causes such as diabetes or vitamin B12 deficiency.
Some people may need to see a neurologist (a specialist in conditions affecting the nervous system) in hospital for further tests such as:
NCS and EMG are usually carried out at the same time.
Your GP can usually identify the underlying cause of a peripheral neuropathy.
If diabetes is suspected, they can usually make a confident diagnosis based on your symptoms, a physical examination and checking the levels of glucose in your blood and urine.
If you're taking a medication known to cause peripheral neuropathy, your GP may temporarily stop or reduce your dose to see whether your symptoms improve.
If the cause is uncertain, you may be referred to a neurologist for more extensive blood tests to check:
You may need a lumbar puncture to test the cerebrospinal fluid (a clear, colourless fluid that surrounds and supports the brain and spinal cord) for inflammation.
Occasionally, a nerve biopsy may be carried out as part of your diagnosis. This is a minor surgical procedure where a small sample of a peripheral nerve is removed from near your ankle so it can be examined under a microscope.
It's then checked for changes that could be a sign of certain types of peripheral neuropathy. However, nerve biopsies are rarely needed.
You may also need a scan to look for any underlying cause of your neuropathy, such as:
Treatment for peripheral neuropathy may include treating any underlying cause or any symptoms you're experiencing.
Treatment may be more successful for certain underlying causes. For example, ensuring diabetes is well controlled may help improve neuropathy or at least stop it getting worse.
There are many different possible causes of peripheral neuropathy, some of which can be treated in different ways. For example:
Some less common types of peripheral neuropathy may be treated with medication, such as:
However, the underlying cause may not always be untreatable.
You may also require medication to treat any nerve pain (neuropathic pain) you're experiencing.
Unlike most other types of pain, neuropathic pain doesn't usually get better with common painkillers, such as paracetamol and ibuprofen and other medications are often used.
These should usually be started at the minimum dose, with the dose gradually increased until you notice an effect, because the ideal dose for each person is unpredictable. Higher doses may be better at managing the pain, but are also more likely to cause side effects.
The most common side effects are tiredness, dizziness or feeling "drunk". If you get these, it may be necessary to reduce your dose. Don't drive or operate machinery if you experience drowsiness or blurred vision. You also may become more sensitive to the effects of alcohol.
The side effects should improve after a week or two as your body gets used to the medication. However, if your side effects continue, tell your GP as it may be possible to change to a different medication that suits you better.
Even if the first medication tried doesn't help, others may.
Many of these medications may also be used for treating other conditions, such as depression, epilepsy, anxiety or headaches. If you're given an antidepressant, this may treat pain even if you're not depressed. This doesn't mean your doctor suspects you're depressed.
The main medications recommended for neuropathic pain include:
There are also some additional medications that can be used to relieve pain in a specific area of the body or to relieve particularly severe pain for short periods. These are described below.
If your pain is confined to a particular area of your body and you can't, or would prefer not to, take the medications above, you may benefit from using capsaicin cream.
Capsaicin is the substance that makes chilli peppers hot and is thought to work in neuropathic pain by stopping the nerves sending pain messages to the brain.
A pea-sized amount of capsaicin cream is rubbed on the painful area of skin three or four times a day.
Side effects of capsaicin cream can include skin irritation and a burning sensation in the treated area when you first start treatment.
Don't use capsaicin cream on broken or inflamed skin and always wash your hands after applying it.
This is a large sticking plaster that contains a local anaesthetic. It's useful when pain affects only a small area of skin. It's stuck over the area of painful skin and the local anaesthetic is absorbed into the skin that's covered.
Tramadol is a powerful painkiller related to morphine that can be used to treat neuropathic pain that doesn't respond to other treatments your GP can prescribe.
Like all opioids, tramadol can be addictive if it's taken for a long time. It will usually only be prescribed for a short time. Tramadol can be useful to take at times when your pain is worse.
Common side effects of tramadol include:
In addition to treating pain, you may also require treatment to help you manage other symptoms you're experiencing as a result of peripheral neuropathy.
For example, if you have muscle weakness, you may need physiotherapy to learn exercises to improve your muscle strength. You may also need to wear splints to support weak ankles or use walking aids to help you get around.
Other problems associated with peripheral neuropathy may be treatable with medication, such as:
In some cases, you may need more invasive treatment, such as botulinum toxin injections for hyperhidrosis or urinary catheterisation if you have problems emptying your bladder.
Peripheral neuropathy can sometimes cause other medical problems, such as foot ulcers and heart rhythm changes, and blood circulation problems.
These complications vary depending on the underlying cause of the condition.
A diabetic foot ulcer is an open wound or sore on the skin that's slow to heal. These are common in people with diabetic polyneuropathy.
If you have numb feet, it's easy to cut your foot by stepping on something sharp.
An ulcer can also occur if you unknowingly develop a blister caused by badly fitting shoes. If you don't feel any pain, you may continue walking without protecting the blister. If the cut or blister gets worse, it may develop into an ulcer.
High blood sugar can damage your blood vessels, causing the blood supply to your feet to become restricted. A reduced blood supply to the skin on your feet means it receives a lower number of infection-fighting cells, which can mean wounds take longer to heal and can lead to gangrene.
If you do develop a wound infection in one of your feet as a result of peripheral neuropathy, there's a risk this could lead to gangrene (death of part of the skin or underlying tissues).
If gangrene does develop, you may need surgery to remove the damaged tissue (known as debridement) and antibiotics to treat any underlying infection. In severe cases your toe or foot may need to be amputated.
If you have diabetes, you should take extra care of your feet. Get your feet checked regularly by a podiatrist (a medical professional, also known as a chiropodist, who specialises in foot care).
Cardiovascular autonomic neuropathy (CAN) is another potentially serious problem that's common in people with diabetic polyneuropathy.
CAN occurs when damage to the peripheral nerves disrupts the automatic functions that control your blood circulation and heartbeat.
The two main noticeable symptoms of CAN are:
You may be able to control the symptoms of orthostatic hypotension by using a number of self care techniques, such as:
In some cases, medication may be required to treat orthostatic hypotension.
Two widely used medications are:
A more serious concern with CAN is that your heart may suddenly develop an abnormal pattern of beating (arrhythmia), which could lead to a cardiac arrest, where your heart stops beating altogether.
To prevent this, you may be prescribed medication to help regulate the beating of your heart, such as flecainide, beta-blockers or amiodarone.
If you have CAN, you'll probably need to have regular check-ups so your heart function can be monitored.