What Is Peripheral Neuropathy?

Today's post from gloshospitals.nhs.uk (see link below) is another general article describing peripheral neuropathy, its causes and its treatments. It's very useful as a starting point for people new to the condition; or family members and friends, trying to understand what's happening to the patient. It's compiled by a hospital group in the UK and can be trusted although there just isn't room in this sort of article for 100% coverage of the disease (people love to point out the smallest details that are missing from this sort of piece). Worth a read for everybody coming into contact with neuropathy.

Painful Peripheral Neuropathy
Pain Service Website, Gloucestershire Hospitals NHS Foundation Trust
Webmaster Dr J G de Courcy, Consultant in Pain Medicine and Anaesthesia 
What is it?

Peripheral neuropathy, a result of nerve damage, is a common cause of numbness and pain in the hands and feet. In some cases this can also be associated with pain which can be very distressing. People typically describe the pain of peripheral neuropathy as tingling or burning, while they may compare the loss of sensation to the feeling of wearing a thin stocking or glove. Because the nerve fibres affected include those involved in telling us where our joints are in space (proprioception) people with peripheral neuropathy often describe problems with balance and may have a tendency to fall.

One of the most common causes is diabetes. Peripheral neuropathy can also sometimes result from problems such as traumatic injuries, infections, metabolic problems such as vitamin deficiencies and exposure to toxins including some drugs: however, in non-diabetic patients it is most common that no other cause can be identified and it can best be described as an ageing process of the nerves. The longest nerve fibres are most readily affected, which is why the feet and hands are most commonly affected.

In many cases, peripheral neuropathy symptoms improve with time — especially if the condition is caused by an underlying condition that can be treated. A number of medications often are used to reduce the painful symptoms of peripheral neuropathy.

What symptoms can it cause?

The nerves of your peripheral nervous system carry information from your brain and spinal cord (central nervous system) to and from all other parts of your body. Several groups of nerves may be affected by peripheral neuropathy:
Sensory nerves that carry sensations back to your Central Nervous System such as heat, pain or touch
Motor nerves that carry impulses to make your muscles contract
Autonomic nerves that control functions such as blood pressure, heart rate, digestion and bladder function

Most commonly, peripheral neuropathy starts in the longest nerve fibres — the ones that reach to your toes. Symptoms vary, depending on which types of nerves are affected. Signs and symptoms may include:
Gradual onset of numbness and tingling in your feet or hands, which may spread upward into your legs and arms. This may be insidious in its onset so that many patients may not be aware of it.
Burning pain
Sharp, jabbing or electric shock-like pain
Extreme sensitivity to touch, even light touch (termed allodynia)
Lack of coordination and balance
Muscle weakness or paralysis if motor nerves are affected
Bowel or bladder problems if autonomic nerves are affected

Peripheral neuropathy may affect one nerve (mononeuropathy), two or more nerves in different areas (multiple mononeuropathy) or many nerves (polyneuropathy).

Causes

Apart from Diabetes, in many patients it is not possible to identify a cause for cause of peripheral neuropathy. Despite this, a number of factors that can cause neuropathies should be considered:
Alcoholism. This may relate both to the alcohol and because many alcoholics also have vitamin deficiencies.
Autoimmune diseases. These include lupus, rheumatoid arthritis and Guillain-Barre syndrome.
Diabetes. When damage occurs to several nerves, the cause frequently is diabetes. At least half of all people with diabetes develop some type of neuropathy.
Exposure to poisons. These may include some toxic substances, such as heavy metals, and certain medications — particularly those used in cancer chemotherapy.
Infections. Certain viral or bacterial infections can cause peripheral neuropathy, including Lyme disease, shingles (varicella-zoster), Epstein-Barr, hepatitis C and HIV/AIDS, and the leprosy bacillus.
Inherited disorders.
Trauma or pressure on the nerve. Traumas and injuries (including surgery) can injure peripheral nerves. Nerve pressure can result from using a cast or crutches..
Tumours. Growths can form directly on the nerves themselves, or tumours can exert pressure on surrounding nerves. Both cancerous (malignant) and noncancerous (benign) tumours can contribute to peripheral neuropathy.
Vitamin deficiencies. B vitamins — B-1, B-6 and B-12 — are particularly important to nerve health. Vitamin E and niacin also are crucial to nerve health.
Other diseases. Kidney disease, liver disease and an underactive thyroid (hypothyroidism) also can cause peripheral neuropathy.
Drugs. A number of drugs, notably some of those used in cancer chemotherapy, can cause peripheral neuropathy.

Complications

Complications of peripheral neuropathy may include:
Risk of injury. Because parts of your body may be numb, you may be less likely to feel temperature changes or pain. This can make you more susceptible to burns or skin injury.
Infection. Make sure to check your feet, as well as any other areas lacking usual sensation, regularly so that you can treat minor injuries before they become infected. This is especially important for people with diabetes, who tend to heal more slowly.

Potential treatments

One goal of treatment is to manage the condition causing your neuropathy. If the underlying cause is corrected, the neuropathy often improves on its own. Another goal of treatment is to relieve the painful symptoms.

Medications
 
Many types of medications can be used to relieve the pain of peripheral neuropathy, including:
Simple analgesics. Mild symptoms may be relieved by over-the-counter pain medications. We would normally be cautious about using strong opioid type pain medications because of potential side-effects, though sometimes these may be tried. Opioid drugs may have some benefit but this has to be considered against the potential adverse effects of these drugs.
Anti-epileptic medications. Drugs such as gabapentin, pregabalin and carbamazepine were originally developed to treat epilepsy. However, doctors often also prescribe them for nerve pain. Side effects may include drowsiness and dizziness.
Capsaicin. A cream containing this naturally occurring substance found in chilli peppers can cause modest improvements in peripheral neuropathy symptoms. This is further discussed at the linked page.
Lidocaine patch. More details are given on a linked page on our site.
Antidepressants. Tricyclic antidepressant medications, such as amitriptyline and nortriptyline, were originally developed to treat depression. However, they have been found to help relieve pain by interfering with chemical processes in your brain and spinal cord that cause you to feel pain. The serotonin and norepinephrine reuptake inhibitor (SNRI) duloxetine also has proved effective for peripheral neuropathy caused by diabetes. Side effects may include nausea, drowsiness, dizziness, decreased appetite and constipation.

Therapies
 
Transcutaneous electrical nerve stimulation (TENS) may help to relieve symptoms. TES is discussed further at the linked page.

The following suggestions can help you manage peripheral neuropathy:
Take care of your feet, especially if you have diabetes. Check your feet daily for signs of blisters, cuts or calluses. Tight shoes and socks can worsen pain and tingling and may lead to sores that won't heal. Wear soft, loose cotton socks and padded shoes. You can use a semicircular hoop, which is available in medical supply stores, to keep bedcovers off hot or sensitive feet.
Exercise. Ask your doctor about an exercise routine that's right for you. Regular exercise may reduce neuropathy pain and can help control blood sugar levels.
Stop smoking. Cigarette smoking can affect circulation, increasing the risk of foot problems and possibly amputation.
Eat healthy meals. If you're at high risk of neuropathy or have a chronic medical condition, healthy eating is especially important to ensure that you get essential vitamins and minerals. Emphasize low-fat meats and dairy products and include lots of fruits, vegetables and whole grains in your diet. Drink alcohol in moderation, if at all.
Avoid prolonged pressure. Don't keep your knees crossed or lean on your elbows for long periods of time. Doing so may cause new nerve damage.

Links

a good summary page on different aspects of peripheral neuropathy is given at the National Institute of Neurological Disorders and Stroke website.

You may also find the www.patient.co.uk page on diabetic neuropathy helpful, as well as the page on the NHS Chices site on this topic.

The Foundation for Peripheral Neuropathy website.

For professionals, the American Academy of Neurologists have published guidelines on the Treeatment of Painful Diabetic Neuropathy. A detailed BMJ review of Painful Diabetic Neuropathy is a useful resource.

http://www.gloshospitals.nhs.uk/en/Wards-and-Departments/Departments/Pain-Management/Different-Pains/Nerve-Pain/Types-of-Nerve-Pain/Painful-Peripheral-Neuropathy/