Peripheral neuropathy

Not a single disease, peripheral neuropathy is nerve damage caused by a number of 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.
• Diabetes. More than half the people with diabetes develop some type of neuropathy.
• Infections. These include certain viral or bacterial infections, including Lyme disease, shingles, Epstein-Barr virus, hepatitis B and C, leprosy, diphtheria, and HIV.
• Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathy.
• Tumors. Growths, cancerous (malignant) and noncancerous (benign), can develop on the nerves or press nerves. Also, polyneuropathy can arise as a result of some cancers related to the body's immune response. These are a form of a degenerative disorder called paraneoplastic syndrome.
• Bone marrow disorders. These include an abnormal protein in the blood (monoclonal gammopathies), a form of bone cancer (myeloma), lymphoma and the rare disease amyloidosis.
• Other diseases. These include kidney disease, liver disease, connective tissue disorders and an underactive thyroid (hypothyroidism).

Other causes of neuropathies include:

• Alcoholism. Poor dietary choices made by people with alcoholism can lead to vitamin deficiencies.
• Exposure to poisons. Toxic substances include industrial chemicals and heavy metals such as lead and mercury.
• Medications. Certain medications, especially those used to treat cancer (chemotherapy), can cause peripheral neuropathy.
• Trauma or pressure on the nerve. Traumas, 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.
• Vitamin deficiencies. B vitamins — including B-1, B-6 and B-12 — vitamin E and niacin are crucial to nerve health.

In a number of cases, no cause can be identified (idiopathic).

Risk factors

Peripheral neuropathy risk factors include:

• Diabetes, especially if your sugar levels are poorly controlled
• Alcohol abuse
• Vitamin deficiencies, particularly B vitamins
• Infections, such as Lyme disease, shingles, Epstein-Barr virus, hepatitis B and C, and HIV
• Autoimmune diseases, such as rheumatoid arthritis and lupus, in which your 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 and skin trauma. You might not feel temperature changes or pain on parts of your body that are numb.
• Infection. Your feet and other areas lacking sensation can become injured without your knowing. Check these areas regularly 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.

Prevention

Manage underlying conditions

The best way to prevent peripheral neuropathy is to manage medical conditions that put you at risk, such as diabetes, alcoholism or rheumatoid arthritis.

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 vitamin B-12 deficiency 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 doctor about B-12 supplements.
• Exercise regularly. With your doctor'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, including repetitive motions, cramped positions that put pressure on nerves, exposure to toxic chemicals, smoking and overindulging in alcohol.

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

• A full medical history. Your doctor will review your medical history, including your symptoms, your lifestyle, exposure to toxins, drinking habits and a family history of nervous system (neurological) diseases.
• Neurological examination. Your doctor might check your tendon reflexes, your muscle strength and tone, your ability to feel certain sensations, and your posture and coordination.

Tests

Your doctor may order tests, including:

• Blood tests. These can detect vitamin deficiencies, diabetes, abnormal immune function and other indications of conditions that can cause peripheral neuropathy.
• Imaging tests. CT or MRI scans can look for herniated disks, tumors or other abnormalities.

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

  At the same time as an electromyogram, your doctor or an EMG technician typically performs a nerve conduction study. Flat electrodes are placed on the skin and a low electric current stimulates the nerves. Your doctor will record your nerves' responses to the electric current.

• Other nerve function tests. These might include an autonomic reflex screen that records how the autonomic nerve fibers work, 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 look for abnormalities.
• Skin biopsy. Your doctor removes a small portion of skin to look for a reduction in nerve endings.

Treatment goals are to manage the condition causing your neuropathy and to relieve symptoms. If your lab tests indicate no underlying condition, your doctor might recommend watchful waiting to see if your neuropathy improves.

Medications

Besides medications used to treat conditions associated with peripheral neuropathy, medications used to relieve peripheral neuropathy signs and symptoms include:

• Pain relievers. Over-the-counter pain medications, such as nonsteroidal anti-inflammatory drugs, can relieve mild symptoms. For more-severe symptoms, your doctor might prescribe painkillers.

  Medications containing opioids, such as tramadol (Conzip, Ultram) or oxycodone (Oxycontin, Roxicodone, others), can lead to dependence and addiction, so these drugs generally are prescribed only when other treatments fail.

• Anti-seizure medications. Medications such as gabapentin (Gralise, Neurontin, Horizant) and pregabalin (Lyrica), developed to treat epilepsy, may relieve nerve pain. Side effects can include drowsiness and dizziness.

• Topical treatments. Capsaicin cream, which contains a substance found in hot peppers, can cause modest improvements in peripheral neuropathy symptoms. You might have skin burning and irritation where you apply the cream, but this usually lessens over time. Some people, however, can't tolerate it.

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

• Antidepressants. Certain tricyclic antidepressants, such as amitriptyline, doxepin (Silenor, Zonalon) and nortriptyline (Pamelor), 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 duloxetine (Cymbalta) and the extended-release antidepressant venlafaxine (Effexor XR) also might ease the pain of peripheral neuropathy caused by diabetes.

  Side effects of antidepressants may include dry mouth, nausea, drowsiness, dizziness, decreased appetite and constipation.

Therapies

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

• Transcutaneous electrical nerve stimulation (TENS). Electrodes placed on the skin deliver a gentle electric current at varying frequencies. TENS should be applied for 30 minutes daily for about a month.

• Plasma exchange and intravenous immune globulin. These procedures, which help suppress immune system activity, might benefit people with certain inflammatory conditions.

  Plasma exchange involves removing your blood, then removing antibodies and other proteins from the blood and returning the blood to your body. In immune globulin therapy, you receive high levels of proteins that work as antibodies (immunoglobulins).

• Physical therapy. If you have muscle weakness, physical therapy can help improve your movements. You may also need hand or foot braces, a cane, a walker, or a wheelchair.
• Surgery. If you have neuropathies caused by pressure on nerves, such as pressure from tumors, you might need surgery to reduce the pressure.

Alternative medicine

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

• Acupuncture. Inserting thin needles into various points on your body might reduce peripheral neuropathy symptoms. You might need multiple sessions before you notice improvement. Acupuncture is generally considered safe when performed by a certified practitioner using sterile needles.
• Alpha-lipoic acid. This has been used as a treatment for peripheral neuropathy in Europe for years. Discuss using alpha-lipoic acid with your doctor because it can affect blood sugar levels. Other side effects can include stomach upset and skin rash.
• Herbs. Certain herbs, such as evening primrose oil, might help reduce neuropathy pain in people with diabetes. Some herbs interact with medications, so discuss herbs you're considering with your doctor.
• 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 reduce neuropathy pain, improve muscle strength and help control blood sugar levels. Gentle routines such as yoga and tai chi might also help.
• Quit smoking. Cigarette smoking can affect circulation, increasing the risk of foot problems and other neuropathy complications.
• Eat healthy meals. Good nutrition is especially important to ensure that you get essential vitamins and minerals. Include fruits, vegetables, whole grains and lean protein in your diet.
• Avoid excessive alcohol. Alcohol can worsen peripheral neuropathy.
• Monitor your blood glucose levels. If you have diabetes, this will help keep your blood glucose under control and might help improve your neuropathy.