Peripheral neuropathy

Overview

Peripheral neuropathy happens when the nerves that are located outside of the brain and spinal cord (peripheral nerves) are damaged. This condition often causes weakness, numbness and pain, usually in the hands and feet. It also can affect other areas and body functions including digestion and urination.

The peripheral nervous system sends information from the brain and spinal cord, also called the central nervous system, to the rest of the body through motor nerves. The peripheral nerves also send sensory information to the central nervous system through sensory nerves.

Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes and exposure to toxins. One of the most common causes of neuropathy is diabetes.

People with peripheral neuropathy usually describe the pain as stabbing, burning or tingling. Sometimes symptoms get better, especially if caused by a condition that can be treated. Medicines can reduce the pain of peripheral neuropathy.

Symptoms

Every nerve in the peripheral system has a specific job. Symptoms depend on the type of nerves affected. Nerves are divided into:

• Sensory nerves that receive sensation, such as temperature, pain, vibration or touch, from the skin.
• Motor nerves that control muscle movement.
• Autonomic nerves that control functions such as blood pressure, sweating, heart rate, digestion and bladder function.

Symptoms of peripheral neuropathy might include:

• Gradual onset of numbness, prickling, or tingling in your feet or hands. These sensations can spread upward into your legs and arms.
• Sharp, jabbing, throbbing or burning pain.
• Extreme sensitivity to touch.
• Pain during activities that shouldn't cause pain, such as pain in your feet when putting weight on them or when they're under a blanket.
• Lack of coordination and falling.
• Muscle weakness.
• Feeling as if you're wearing gloves or socks when you're not.
• Inability to move if motor nerves are affected.

If autonomic nerves are affected, symptoms might include:

• Heat intolerance.
• Excessive sweating or not being able to sweat.
• Bowel, bladder or digestive problems.
• Drops in blood pressure, causing dizziness or lightheadedness.

Peripheral neuropathy can affect one nerve, called mononeuropathy. If it affects two or more nerves in different areas, it's called multiple mononeuropathy, and if it affects many nerves, it's called polyneuropathy. Carpal tunnel syndrome is an example of mononeuropathy. Most people with peripheral neuropathy have polyneuropathy.

When to see a doctor

Seek medical care right away if you notice unusual tingling, weakness, or pain in your hands or feet. Early diagnosis and treatment give you the best chance for controlling your symptoms and preventing further damage to your peripheral nerves.

Causes

Peripheral neuropathy is nerve damage caused by several different conditions. Health conditions that can cause peripheral neuropathy include:

• Autoimmune diseases. These include Sjogren's syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and vasculitis. Also, some cancers related to the body's immune system can cause polyneuropathy. These are a form of autoimmune disorder called paraneoplastic syndrome.
• Diabetes and metabolic syndrome. This is the most common cause. Among people with diabetes, more than half will develop some type of neuropathy.
• Infections. These include certain viral or bacterial infections, including Lyme disease, shingles, hepatitis B and C, leprosy, diphtheria, and HIV.
• Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathy that run in families.
• Tumors. Cancerous growths, also called malignant, and noncancerous growths, also called benign, can grow on or press on nerves.
• Bone marrow disorders. These include a protein in the blood that isn't usually there, called monoclonal gammopathies, a rare form of myeloma that affects the bones, lymphoma and the rare disease amyloidosis.
• Other diseases. These include metabolic conditions such as kidney disease or liver disease, and an underactive thyroid, also known as hypothyroidism.

Other causes of neuropathies include:

• Alcohol use disorder. Unhealthy dietary choices made by people with alcohol use disorder, also known as alcoholism, and poor absorption of vitamins can lead to low amounts of essential vitamins in the body.
• Exposure to poisons. Toxic substances include industrial chemicals and heavy metals such as lead and mercury.
• Medicines. Certain medicines, especially chemotherapy used to treat cancer, can cause peripheral neuropathy.
• Injury or pressure on the nerve. Injuries, such as from motor vehicle accidents, falls or sports injuries, can sever or damage peripheral nerves. Nerve pressure can result from having a cast or using crutches or repeating a motion such as typing many times.
• Low vitamin levels. B vitamins, including B-1, B-6 and B-12, as well as copper and vitamin E are crucial to nerve health.

In some cases, no cause can be identified. This is called idiopathic peripheral neuropathy.

Risk factors

Peripheral neuropathy risk factors include:

• Diabetes, especially if your sugar levels are not controlled well.
• Alcohol misuse.
• Low levels of vitamins in the body, especially vitamin B-12.
• Infections, such as Lyme disease, shingles, hepatitis B and C, and HIV.
• Autoimmune diseases, such as rheumatoid arthritis and lupus, in which the immune system attacks your own tissues.
• Kidney, liver or thyroid disorders.
• Exposure to toxins.
• Repetitive motion, such as those performed for certain jobs.
• Family history of neuropathy.

Complications

Complications of peripheral neuropathy can include:

• Burns, skin injuries and wounds on the feet. You might not feel temperature changes or pain on parts of your body that are numb.
• Infection. Your feet and other areas that lack sensation can become injured without your knowing. Check these areas regularly, wear close-toed, well-fitting shoes and treat minor injuries before they become infected, especially if you have diabetes.
• Falls. Weakness and loss of sensation may be associated with lack of balance and falling. Installing handrails in the bathroom, using canes or walkers when needed, and ensuring that you are walking only in well-lit rooms can decrease fall risk.

Prevention

Manage underlying conditions

The best way to prevent peripheral neuropathy is to manage medical conditions that put you at risk.

Make healthy lifestyle choices

These habits support your nerve health:

• Eat a diet rich in fruits, vegetables, whole grains and lean protein to keep nerves healthy. Protect against low levels of vitamin B-12 by eating meats, fish, eggs, low-fat dairy foods and fortified cereals. If you're vegetarian or vegan, fortified cereals are a good source of vitamin B-12, but talk to your health care professional about B-12 supplements.
• Exercise regularly. With a health care professional's OK, try to get at least 30 minutes to one hour of exercise at least three times a week.
• Avoid factors that may cause nerve damage. These factors can include repetitive motions, exposure to toxic chemicals, smoking and drinking too much alcohol.

Diagnosis

Peripheral neuropathy has many possible causes. Besides a physical exam, which may include blood tests, diagnosis usually requires:

• A full medical history. Your health care professional will look at your medical history. The history will include your symptoms, lifestyle, exposure to toxins, drinking habits and a family history of nervous system, or neurological, diseases.
• Neurological exam. Your care professional might check your tendon reflexes, muscle strength and tone, ability to feel certain sensations, and balance and coordination.

Tests

A health care professional may order tests, including:

• Blood tests. These can detect low levels of vitamins, diabetes, signs of inflammation or metabolic issues that can cause peripheral neuropathy.
• Imaging tests. CT or MRI scans can look for herniated disks, pinched nerves, also called compressed nerves, growths or other problems affecting the blood vessels and bones.

• Nerve function tests. Electromyography (EMG) measures and records electrical activity in your muscles to find nerve damage. A thin needle (electrode) is inserted into the muscle to measure electrical activity as you contract the muscle.

  During an EMG, a nerve conduction study is typically also done. Flat electrodes are placed on the skin and a low electric current stimulates the nerves. A health care professional will record how the nerves respond to the electric current.

• Other nerve function tests. These might include an autonomic reflex screen. This test records how the autonomic nerve fibers work. Other tests can include a sweat test that measures your body's ability to sweat and sensory tests that record how you feel touch, vibration, cooling and heat.
• Nerve biopsy. This involves removing a small portion of a nerve, usually a sensory nerve, to try to find the cause of the neuropathy.
• Skin biopsy. A small portion of skin is removed to look at the number of nerve endings.

Treatment

Treatment goals are to manage the condition causing your neuropathy and to improve symptoms. If your lab tests show no condition that's causing the neuropathy, your health care professional might recommend watchful waiting to see if your neuropathy stays the same or gets better.

Medicines

Medicines can be used to treat conditions associated with peripheral neuropathy. There also are medicines used to improve peripheral neuropathy symptoms. These medicines include:

• Pain relievers. Medicines available without a prescription, such as nonsteroidal anti-inflammatory drugs, can improve mild symptoms.
• Anti-seizure medicines. Medicines such as gabapentin (Gralise, Neurontin, Horizant) and pregabalin (Lyrica), developed to treat epilepsy, often improve nerve pain. Side effects can include drowsiness and dizziness.

• Topical treatments. Lidocaine cream that is available without a prescription can be applied to the skin.

  Lidocaine patches are another treatment you apply to the skin to improve pain. Side effects can include drowsiness, dizziness and numbness at the site of the patch.

• Antidepressants. Certain tricyclic antidepressants, such as amitriptyline and nortriptyline (Pamelor), can help improve pain. These medicines interfere with chemical processes in the brain and spinal cord that cause you to feel pain.

  The serotonin and norepinephrine reuptake inhibitor duloxetine (Cymbalta) and the extended-release antidepressants venlafaxine (Effexor XR) and desvenlafaxine (Pristiq) also might improve peripheral neuropathy pain caused by diabetes.

  Side effects of antidepressants may include dry mouth, nausea, drowsiness, dizziness, changes in appetite, weight gain and constipation.

Therapies

Various therapies and procedures might help with the symptoms of peripheral neuropathy.

• Scrambler therapy. This treatment uses electrical impulses to send nonpain messages to the brain. These messages replace the pain messages the nerves send to the brain. The goal is to retrain the brain to think there is no pain.
• Spinal cord stimulation. This type of therapy works through devices put into the body. These devices are called neurostimulators. They send low-level electrical impulses that can block pain signals from reaching the brain.
• Plasma exchange, steroids and intravenous immune globulin. These treatments are often used if inflammation or autoimmune conditions are causing neuropathy with weakness, numbness or imbalance. These therapies are not used to treat pain alone.
• Physical therapy. If you have muscle weakness or issues with balance, physical therapy can help improve your ability to move. You also may need hand or foot braces, a cane, a walker, or a wheelchair.
• Surgery. Neuropathies caused by pressure on nerves, such as from tumors, might require surgery.

Alternative medicine

Some people with peripheral neuropathy try complementary treatments for relief. Researchers haven't studied these techniques as thoroughly as they have most medicines. But the following therapies have shown some promise:

• Acupuncture. Inserting thin needles into various points on your body might lower peripheral neuropathy symptoms. You might need multiple sessions before you see improvement. Acupuncture is generally considered safe when done by a certified practitioner using sterile needles.
• Alpha-lipoic acid. This has been used as a treatment for peripheral neuropathy in Europe for years and there is some evidence that it can be helpful in those with painful diabetic neuropathy. Discuss using alpha-lipoic acid with your health care professional because it can affect blood sugar levels. Other side effects can include stomach upset and skin rash.
• Amino acids. Amino acids, such as acetyl-L-carnitine, might benefit people who have undergone chemotherapy and people with diabetes. Side effects might include nausea and vomiting.

Lifestyle and home remedies

To help you manage peripheral neuropathy:

• Take care of your feet, especially if you have diabetes. Check daily for blisters, cuts or calluses. 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. Regular exercise, such as walking three times a week, can lower neuropathy pain, improve muscle strength and help control blood sugar levels. Gentle routines such as yoga and tai chi also might help. If you have painful neuropathy in your feet, you may want to try pool-based exercise such as swimming.
• Quit smoking. Cigarette smoking can cause problems with circulation. This increases the risk of foot problems and other neuropathy complications.
• Eat healthy meals. Good nutrition is especially important to make sure that you get important vitamins and minerals. Include fruits, vegetables, whole grains and lean protein in your diet.
• Avoid excessive alcohol. Alcohol can make peripheral neuropathy worse.
• Monitor your blood sugar levels. If you have diabetes, this will help keep your blood sugar under control and might help improve your neuropathy.

Preparing for an appointment

You're likely to start by seeing your health care professional. You may then be referred to a doctor trained in nervous system disorders, also called a neurologist.

Here's information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fasting for a specific test. Make a list of:

• Your symptoms, including any that may seem like they're not related to your reason for scheduling the appointment.
• Key personal information, including recent stresses or major life changes, family medical history and alcohol use.
• All medicines, vitamins or other supplements you take, including doses.
• Questions to ask your health care professional.

Take a family member or friend along, if possible, to help you remember the information you're given.

For peripheral neuropathy, basic questions to ask include:

• What's the most likely cause of my symptoms?
• Are there other possible causes?
• What tests do I need?
• Is this condition temporary or long lasting?
• What treatments are available, and which do you recommend?
• What side effects can I expect from treatment?
• Are there alternatives to the approach you're suggesting?
• I have other health conditions. How can I best manage them together?
• Do I need to limit activities?
• Are there brochures or other printed material I can take? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your health care professional is likely to ask you questions, such as:

• Do you have health conditions, such as diabetes or kidney disease?
• When did your symptoms begin?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• Does anything seem to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• Does anyone in your family have symptoms similar to yours?
• Have you fallen in the past year?
• Have you had any injuries to your feet?