Overview of Peripheral Neuropathy
Peripheral neuropathy develops when nerves in the body’s extremities, such as the hands, feet and arms, are damaged. Diabetes is a leading cause, but neuropathy can be inherited or caused by infections, other diseases, and trauma. The symptoms depend on which nerves are affected. Nerve signalling in neuropathy is disrupted in three ways:
- loss of signals normally sent (like a broken wire)
- inappropriate signalling when there shouldn’t be any (like static on a telephone line)
- errors that distort the messages being sent (like a wavy television picture)
Symptoms can range from mild to disabling and are rarely life-threatening. The symptoms depend on the type of nerve fibres affected and the type and severity of the damage. Symptoms may develop over days, weeks, or years. In some cases, the symptoms improve on their own and may not require advanced care. Unlike nerve cells in the central nervous system, peripheral nerve cells continue to grow throughout life.
The peripheral nervous system
The peripheral nervous system is the network of nerves that exist outside the central nervous system (the brain and spinal cord). It includes different types of nerves with their own specific functions, including:
- sensory nerves – responsible for transmitting sensations, such as pain and touch
- motor nerves – responsible for controlling muscles
- autonomic nerves – responsible for regulating automatic functions of the body, such as blood pressure and bladder function
Symptoms of peripheral neuropathy
The main symptoms of peripheral neuropathy can include:
- numbness and tingling in the feet or hands
- burning, stabbing or shooting pain in affected areas
- loss of balance and coordination
- muscle weakness, especially in the feet
These symptoms are usually constant, but they may come and go.
When to see a GP
It’s important to see your GP if you experience the early symptoms of peripheral neuropathy:
- pain, tingling/loss of sensation in the feet
- loss of balance or weakness
- a cut or ulcer on your foot that’s not getting better
It’s also recommended that people at the highest risk of peripheral neuropathy, such as those with diabetes, have regular check-ups. In the UK, it is estimated almost one in ten people aged 55 or over are affected by peripheral neuropathy. A 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 health problems affecting the nervous system.
Generally, the sooner peripheral neuropathy is diagnosed, the better the chance of limiting the damage and preventing further complications.
Causes of peripheral neuropathy
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:
- physical injury to the nerves
- a viral infection, such as shingles
- a side effect of certain medicines or drinking too much alcohol
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.
Treating peripheral neuropathy
Treatment for peripheral neuropathy depends on the symptoms and underlying cause.
Not all 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 medicines called neuropathic pain agents, as standard painkillers often do not work.
If you have other symptoms associated with peripheral neuropathy, these may need to be treated individually. For example, treatment for muscle weakness may involve physiotherapy and walking aids.
Complications of peripheral neuropathy
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 is not treated, you may be at risk of developing potentially serious complications, such as a foot ulcer that becomes infected. This can lead to gangrene if untreated and, in severe cases, may mean the 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.
Different types of peripheral neuropathy
Peripheral neuropathy may affect:
- only one nerve (mononeuropathy)
- several nerves (mononeuritis multiplex)
- all the nerves in the body (polyneuropathy)
Polyneuropathy is the most common type and starts by affecting the longest nerves first, so symptoms typically begin in the feet. Over time it gradually starts to affect shorter nerves, so it feels as if it is spreading upwards, and later affects the hands.
Symptoms vary according to the type of peripheral neuropathy. It may develop quickly or slowly over time.
The main types of peripheral neuropathy include:
- sensory neuropathy – damage to the nerves that carry messages of touch, temperature, pain and other sensations to the brain
- motor neuropathy – damage to the nerves that control movement
- autonomic neuropathy – damage to the nerves that control involuntary bodily processes, such as digestion, bladder function and control of blood pressure
- mononeuropathy – damage to a single nerve outside of the central nervous system
In many cases, someone with peripheral neuropathy may have more than one of these types of peripheral neuropathy simultaneously.
A combination of sensory and motor neuropathy is particularly common (called sensorimotor polyneuropathy).
Symptoms of sensory neuropathy can include:
- pins and needles in the affected body part
- numbness and less ability to feel pain or changes in temperature, particularly in your feet
- a burning or sharp pain, usually in the feet
- feeling pain from something that should not be painful at all, such as a very light touch
- loss of balance or coordination caused by less ability to tell the position of the feet or hands
Symptoms of motor neuropathy can include:
- twitching and muscle cramps
- muscle weakness or paralysis affecting one or more muscles
- thinning (wasting) of muscles
- difficulty lifting the front part of your foot and toes, particularly noticeable when walking (foot drop)
Symptoms of autonomic neuropathy can include:
- constipation or diarrhoea, particularly at night
- feeling sick, bloating and belching
- low blood pressure, which can make you feel faint or dizzy when you stand up
- rapid heartbeat (tachycardia)
- excessive sweating or a lack of sweating
- problems with sexual function, such as erectile dysfunction in men
- difficulty emptying your bladder of urine
- loss of bowel control
Depending on the specific nerve affected, symptoms of mononeuropathy can include:
- altered sensation or weakness in the fingers
- double vision or other problems with focusing your eyes, sometimes with eye pain
- weakness of one side of your face (Bell’s palsy)
- foot or shin pain, weakness or altered sensation
The most common type of mononeuropathy is carpal tunnel syndrome. The carpal tunnel is a small ‘tunnel’ in your wrist.
In carpal tunnel syndrome, 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. Other health conditions and certain medicines can also cause neuropathy. No cause can be identified in some cases – 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 sugar in your blood damaging the tiny blood vessels that supply your nerves. Peripheral neuropathy becomes more likely the longer you have had diabetes.
Up to one in four 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:
- regularly drink large amounts of alcohol
- are over 40 years old
If you have diabetes, examine your feet regularly to check for open wounds or sores (ulcers) 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:
- excessive alcohol drinking for years
- low levels of vitamin B12 or other vitamins
- physical damage to the nerves, such as from an injury or during surgery
- an underactive thyroid gland
- certain infections, such as shingles, Lyme disease, diphtheria, botulism and HIV
- inflammation of the blood vessels
- chronic liver disease or chronic kidney disease
- the presence of an abnormal protein in the blood (monoclonal gammopathy of undetermined significance, or MGUS)
- certain types of cancer, such as lymphoma, a cancer of the lymphatic system, and multiple myeloma, a type of bone marrow cancer
- Charcot-Marie-Tooth (CMT) disease and other types of hereditary motor sensory neuropathy, genetic conditions that cause nerve damage, particularly in the feet
- having high levels of toxins in your body, such as arsenic, lead or mercury
- Guillain-Barré syndrome – a rare condition that causes rapid onset of paralysis within days
- amyloidosis, a group of rare but serious health conditions caused by deposits of abnormal protein called amyloid in tissues and organs throughout the body
- health conditions caused by overactivity of the immune system, such as rheumatoid arthritis, lupus, Sjögren’s syndrome or coeliac disease
A few medicines may sometimes cause peripheral neuropathy as a side effect in some people.
- some types of chemotherapy for cancer, especially for bowel cancer, lymphoma or myeloma
- some antibiotics, if taken for months, such as metronidazole or nitrofurantoin
- phenytoin (used to treat epilepsy) if taken for a long time
- amiodarone and thalidomide
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.
Confirming if you have a neuropathy
Some people may need to see a neurologist, a specialist in health conditions affecting the nervous system, in hospital for further tests. These may include:
- a nerve conduction test (NCS), where small metal wires called electrodes are placed on your skin that release tiny electric shocks to stimulate your nerves; the speed and strength of the nerve signal is measured
- electromyography (EMG), where a small needle is inserted through your skin into your muscle and used to measure the electrical activity of your muscles
NCS and EMG are usually carried out at the same time.
Identifying the cause of a neuropathy
Your GP can usually identify the underlying cause of peripheral neuropathy. If diabetes is suspected, they can generally make a confident diagnosis based on your symptoms, a physical examination, and checking the levels of sugar in your blood and urine.
If you’re taking a medicine 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 blood tests to check:
- whether you have a rare acquired cause that may be responsible
- whether you have a genetic abnormality, such as Charcot-Marie-Tooth disease
You may need a lumbar puncture to test a clear, colourless fluid that surrounds and supports the brain and spinal cord (cerebrospinal fluid) for inflammation.
BIOPSY AND SCANS
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 for examination under a microscope. It’s then checked for changes that could signify certain types of peripheral neuropathy. But 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 symptoms. Treatment may be more successful for certain underlying causes. For example, ensuring diabetes is well controlled may help improve neuropathy or stop it from getting worse.
Treating the underlying cause
There are several different causes of peripheral neuropathy, some of which can be treated differently from others. For example:
- diabetes can sometimes be controlled by lifestyle changes, such as stopping smoking, cutting down on alcohol, maintaining a healthy weight and exercising regularly
- vitamin B12 deficiency can be treated with B12 injections or tablets
- peripheral neuropathy caused by a medicine you’re taking may improve if the medicine is stopped
Some less common types of peripheral neuropathy may be treated with medicines, such as:
- steroids – powerful anti-inflammatory medicines
- immunosuppressants – medicines that reduce the activity of the immune system
- injections of immunoglobulin – a mixture of blood proteins called antibodies made by the immune system
But the underlying cause may not always be treatable.
Relieving nerve pain
You may also require medicine to treat any nerve pain (neuropathic pain) you’re experiencing.
Unlike most other types of pain, neuropathic pain does not usually get better with common painkillers, such as paracetamol and ibuprofen, and other medicines are often used. These should usually be started at the minimum dose, gradually increasing until you notice an effect. Higher doses may better manage 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.
Do not 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 medicine. But 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 medicine tried does not help, others may.
Many of these medicines may also be used for treating other health 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 does not mean your doctor suspects you’re depressed.
The main medicines recommended for neuropathic pain include:
- amitriptyline – also used for the treatment of headaches and depression
- duloxetine – also used for the treatment of bladder problems and depression
- pregabalin and gabapentin – also used to treat epilepsy, headaches or anxiety
There are also some additional medicines that you can take to relieve pain in a specific area of your body or to relieve particularly severe pain for short periods.
If your pain is confined to a particular area of your body, 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. Rub a pea-sized amount of capsaicin cream on the painful area of skin 3 or 4 times a day.
Side effects of capsaicin cream can include skin irritation and a burning sensation in the treated area at the start of treatment. Do not use capsaicin cream on broken or inflamed skin, and always wash your hands after applying it.
Tramadol is a powerful painkiller related to morphine that can be used to treat neuropathic pain that does not respond to other treatments your GP can prescribe.
Like all opioids, tramadol can be addictive if it’s taken for a long time. It’ll 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:
- feeling sick or vomiting
Treating other symptoms
In addition to treating pain, you may also require treatment to help you manage other symptoms.
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 medicines. For example:
In some cases, you may need more invasive treatment, such as:
- botulinum toxin injections for hyperhidrosis
- a urinary catheter if you have problems emptying your bladder
Alternative and complementary therapies
As peripheral neuropathy can be a painful and troublesome problem that may only be partially relieved by standard treatments, you may be tempted to try other therapies. These may include:
- herbal medicine
- benfotiamine (a form of vitamin B1) supplements
- alpha-lipoic acid (an antioxidant) supplements
But while some people may find these helpful, the evidence for them is not always clear. It would be best if you spoke to your doctor before trying these treatments in case they could interfere with your ongoing treatment.
Peripheral neuropathy can sometimes cause other medical problems, such as foot ulcers, heart rhythm changes and blood circulation problems. These complications vary depending on the underlying cause of peripheral neuropathy.
Diabetic foot ulcer
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 come on if you unknowingly develop a blister caused by badly fitting shoes. If you do not feel any pain, you may continue walking without protecting the blister. If the cut or blister worsens, 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 get a wound infection in one of your feet due to peripheral neuropathy, there’s a risk this could lead to gangrene. If gangrene does develop, you may need surgery to remove the damaged tissue 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 (also known as a chiropodist) who specialises in foot care.
Heart and blood circulation problems
Cardiovascular autonomic neuropathy (CAN) is a potentially serious heart and blood circulation problem common in people with diabetic polyneuropathy.
CAN happens 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:
- an inability to exercise for very long
- low blood pressure that can make you feel dizzy or faint when you stand up
You may be able to control the symptoms of low blood pressure by:
- standing or sitting up slowly and gradually
- drinking plenty of fluids to increase the volume of your blood and raise your blood pressure
- wearing compression stockings to help prevent blood from falling back down into your legs
- tilting your bed by raising it at the head end
In some cases, you may need to take medicine for low blood pressure. These are most likely to be:
- fludrocortisone, which works by increasing the volume of your blood
- midodrine, which works by tightening your blood vessels
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.
You may be prescribed medicine to help regulate the beating of your heart, such as flecainide, beta-blockers or amiodarone, to prevent this.
If you have CAN, you will probably need regular medical check-ups to monitor your heart function.
Charcot Foot and Diabetes
When you have diabetes and peripheral neuropathy (nerve damage), you’re more at risk of developing something called Charcot foot – it is a serious foot complication about which you should be aware. It can be difficult to deal with, but having treatment as early as possible can reduce your risk of further problems, like developing a foot ulcer or needing an amputation.
Diabetes UK: Symptoms of Charcot foot
The signs and symptoms of Charcot foot may include:
- warmth – the affected foot feels warmer than the other
- change in foot colour
- change in foot shape.
If you notice any of these symptoms in your feet, take the weight off that foot immediately and talk to your doctor, foot care team or local health service for more information and advice.
How to prevent Charcot foot
If you have lived with diabetes for a long time, or if you have nerve damage in your feet, you are at an increased risk of developing Charcot foot. But the good news is there are things you can do to reduce this risk. Checking your feet every day can help you spot the symptoms or any unusual changes to your foot. You may also be able to get support from your foot specialist if you have neuropathy.
Stopping smoking and keeping your blood sugar levels, blood fats, and blood pressure within your target range can also prevent Charcot foot from developing. And it’s important to avoid big changes to the amount of day to day physical activity you do.
Treatment for Charcot foot
If you are diagnosed with Charcot foot, there are two treatment types available to you.
- Non-surgical treatment: Non-surgical treatment involves keeping the foot as still as possible. This means you will not be able to put any weight on your affected foot. To help you to cope, your foot will be placed in a plaster cast, or you will be given a protective boot. Your foot care team may also give you a wheelchair or crutches, as you’ll need them to move around. The process can take several months or longer, depending on your individual diagnosis. You may also be given custom shoes after your treatment to keep your foot protected and prevent a foot ulcer from developing. Keeping your foot still is really important as it will give the bone time to heal.
- Surgical treatment: If non-surgical treatment is not an option for you, you may need to have surgery. Your foot care team will discuss this with you. The type of surgery you will need depends on your individual diagnosis, and you may need to have more than one operation. Your doctor will be able to talk you through this, along with the risks and benefits involved in the surgery.
Depending on the damage to your foot, you may need to have it reshaped so that you can start to bear weight on it again over time. This type of surgery may mean you need to have the bones and joints in your foot all moved into their original place. If reshaping the foot and constant rest doesn’t help, you may need an amputation. Your diabetes team will support you through this. We know that this type of treatment can be worrying, but in most cases, Charcot foot doesn’t have to result in surgery or an amputation. Regularly checking your feet for the symptoms and getting treatment as soon as possible can help prevent these complications from developing.
Sources and Further Reference
Caution: Nothing in this paper should be construed or is intended as advice. No articles published by us, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician/medical practitioner.
- Except where otherwise noted, the text for this section excerpted from NHS, © Crown Copyright acknowledged. See sources for hyperlink. ↑
- Source: https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Peripheral-Neuropathy-Fact-Sheet ↑
- Charcot foot text excerpted from Diabetes UK – see Sources for hyperlink. © acknowledged ↑