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.
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 your GP
It’s important to see your GP if you experience the early symptoms of peripheral neuropathy, such as:
- pain, tingling or loss of sensation in the feet
- loss of balance or weakness
- a cut or ulcer on your foot that isn’t getting better
It’s also recommended that people at the 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.
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 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 now described.
Symptoms of sensory neuropathy can include:
- prickling and tingling sensation in the affected body part (pins and needles)
- numbness and less of an 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 (allodynia)
- loss of balance or co-ordination caused by less ability to tell the position of the feet or hands (sensory ataxia)
Symptoms of motor neuropathy can include:
- twitching and muscle cramps
- muscle weakness or paralysis affecting one or more muscles
- thinning (wasting) of muscles (atrophy)
- foot drop– difficulty lifting up the front part of your foot and toes, particularly noticeable when walking
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:
- constipation or diarrhoea, particularly at night
- feeling sick, bloating and belching
- low blood pressure(postural or orthostatic hypotension), which can make you feel faint or dizzy when standing up
- rapid heartbeat (tachycardia)
- excessive sweating or a lack of sweating
- problems with sexual function, such as erectile dysfunction in men
- difficulty fully emptying your bladder of urine
- bowel incontinence (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 (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.
Causes of peripheral neuropathy
In Nigeria, diabetes (both type 1 and type 2) is the most common cause of peripheral neuropathy.
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 medications 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.
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 associated with peripheral neuropathy, these may need to be treated individually. For example, treatment for muscle weakness may involve physiotherapy and the use of 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 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.
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 feels as if it’s spreading upwards, later affecting the hands.
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 conditions affecting the nervous system) in hospital for further tests such as:
- a nerve conduction test (NCS) – where small metal wires called electrodes are placed on your skin which release tiny electric shocks that 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 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:
- 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 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.
Treating the underlying cause
There are many different possible 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 medication you’re taking may improve if the medication is stopped
Some less common types of peripheral neuropathy may be treated with medication, such as:
- corticosteroids– powerful anti-inflammatory medication
- immunosuppressants – medications that reduce the activity of the immune system
- injections of immunoglobulin – mixture of blood proteins called antibodies made by the immune system
However, the underlying cause may not always be treatable.
Treating other symptoms
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:
Alternative and Complementary Treatments
As peripheral neuropathy can be a very painful and troublesome condition that may only partly be relieved by medication, some people may be tempted to try other treatments, such as:
- herbal medicine
- benfotiamine (a form of vitamin B1) supplements
- alpha-lipoic acid (an antioxidant) supplements
However, while some people may find these helpful, the evidence for them isn’t always clear. It’s advisable to speak 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 and heart rhythm changes, and blood circulation problems.
These complications vary depending on the underlying cause of the condition.
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 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)
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:
- an inability to exercise for more than a very short period of time
- orthostatic hypotension – a type of low blood pressure that can make you feel dizzy or faint when you stand up
You may be able to control the symptoms of orthostatic hypotension by using a number of self care techniques, such as:
- 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, medication may be required to treat orthostatic hypotension.
Two widely used medications are:
- 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.
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.