Периферическая невропатия

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 almost 1 in 10 people aged 55 or over are affected by peripheral neuropathy.

The peripheral nervous system

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:

• 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 co-ordination
• muscle weakness, especially in the feet

These symptoms are usually constant, but may come and go.

When to see a GP

It's important to see a GP if you experience the early symptoms of peripheral neuropathy.

These include:

• pain, tingling or 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 highest risk of peripheral neuropathy, such as people with diabetes, have regular check-ups.

A GP will ask about your symptoms and may arrange some tests to help identify the underlying cause.

You may be referred to 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 1 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 feels as if it's spreading upwards, and later affects the hands.

 Symptoms Peripheral neuropathy 

Symptoms vary according to the type of peripheral neuropathy and may develop quickly or slowly.

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 at the same time.

A combination of sensory and motor neuropathy is particularly common (sensorimotor polyneuropathy).

Sensory neuropathy

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 co-ordination caused by less ability to tell the position of the feet or hands

Motor neuropathy

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 up the front part of your foot and toes, particularly noticeable when walking (foot drop)

Autonomic neuropathy

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

Mononeuropathy

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.

 Causes Peripheral neuropathy 

Diabetes is the most common cause of peripheral neuropathy in the UK.

Neuropathy can also be caused by other health conditions and certain medicines.

In some cases, no cause can be identified and this is termed idiopathic neuropathy.

Diabetes

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 1 in 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:

• smoke
• 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.

Other causes

As well as diabetes, there are many other possible causes of peripheral neuropathy.

Health conditions

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

Medicines

A few medicines may sometimes cause peripheral neuropathy as a side effect in some people.

These include:

• 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

 Diagnosis Peripheral neuropathy 

A number of tests may be used to diagnose peripheral neuropathy and its underlying cause.

When you see a GP, they'll ask about your symptoms and examine the affected area of your body. This may involve testing sensation, strength and reflexes.

The GP may also arrange blood tests, especially to check for causes such as diabetes or vitamin B12 deficiency.

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 

The 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 sugar in your blood and urine.

If you're taking a medicine known to cause peripheral neuropathy, the 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 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. But nerve biopsies are rarely needed.

You may also need a scan to look for any underlying cause of your neuropathy, such as:

• an X-ray
• a CT scan
• an MRI scan

 Treatment Peripheral neuropathy 

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 at least stop it getting worse.

Treating the underlying cause

There are many different causes of peripheral neuropathy, some of which can be treated in different ways.

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, with the dose gradually increased until you notice an effect.

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.

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 a GP as it may be possible to change to a different medicine 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 the doctor suspects you're depressed.

The main medicines recommended for neuropathic pain include:

• amitriptyline – also used for treatment of headaches and depression
• duloxetine – also used for 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.

Capsaicin cream and patch

You may benefit from using capsaicin, which comes as a cream or a patch you wear on your skin.

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.

Side effects of capsaicin cream and patch can include skin irritation and a burning or itching sensation in the treated area. It might also affect your heart rate and blood pressure.

Do not use capsaicin products on broken or inflamed skin, and always wash your hands after applying cream. The patches are usually put on at a clinic, by a doctor or nurse.

 Capsaicin shortages 

There are currently supply problems with capsaicin cream. If it is not available, talk to your doctor about other treatments that may help you.

Tramadol

Tramadol is a powerful painkiller related to morphine that can be used to treat neuropathic pain that does not respond to other treatments a 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
• dizziness
• constipation

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:

• erectile dysfunction
• constipation
• the slow movement of food through your stomach (gastroparesis)

In some cases, you may need more invasive treatment, such as:

• botulinum toxin injections for excessive sweating (hyperhidrosis) 
• a urinary catheter if you have problems emptying your bladder

Alternative and complementary therapies

As peripheral neuropathy can be a very painful and troublesome problem that may only partly be relieved by standard treatments, you may be tempted to try other therapies.

These may include:

• acupuncture
• 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.

Speak to a doctor before trying these treatments in case they could interfere with your ongoing treatment.

 Complications Peripheral neuropathy 

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 the 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 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.

Gangrene

If you get a wound infection in one of your feet as a result of 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, a medical professional (also known as a chiropodist) who specialises in foot care.

Read more about preventing gangrene and taking care of your feet if you have diabetes.

Heart and blood circulation problems

Cardiovascular autonomic neuropathy (CAN) is a potentially serious heart and blood circulation problem that's 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 2 main noticeable symptoms of CAN are:

• an inability to exercise for more than a very short period of time
• low blood pressure that can make you feel dizzy or faint when you stand up

Treating CAN

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 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'll probably need to have regular check-ups so your heart function can be monitored.