What is Peripheral Neuropathy?
Your peripheral nervous system sends information from your brain and spinal cord (central nervous system) to the rest of your body. Peripheral neuropathy occurs due to damage to your peripheral nerves. It often causes weakness, numbness and pain, usually in your hands and feet. It can also affect other areas of your body.
People with peripheral neuropathy generally describe the pain as stabbing, burning or tingling. In many cases, symptoms improve, especially if caused by a treatable condition. Medications can reduce the pain of peripheral neuropathy.
What are the Causes?
Peripheral neuropathy is not a single disease, but rather is nerve damage caused by a number of conditions. Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes and exposure to toxins. One of the most common causes is diabetes mellitus.
Other Causes of Neuropathies Include:
- Alcoholism. Poor dietary choices made by people with alcoholism can lead to vitamin deficiencies.
- Autoimmune diseases. These include Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and necrotizing vasculitis.
- Diabetes. More than half the people with diabetes develop some type of neuropathy.
- Exposure to poisons. Toxic substances include heavy metals or chemicals.
- Medications. Certain medications, especially those used to treat cancer (chemotherapy), can cause peripheral neuropathy.
- Infections. These include certain viral or bacterial infections, including Lyme disease, shingles, Epstein-Barr virus, hepatitis C, leprosy, diphtheria and HIV.
- Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of 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 for long periods of time.
- 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 paraneoplastic syndrome.
- Vitamin deficiencies. B vitamins — including B-1, B-6 and B-12 — vitamin E and niacin are crucial to nerve health.
- Bone marrow disorders. These include abnormal protein in the blood (monoclonal gammopathies), a form of bone cancer (osteosclerotic myeloma), lymphoma and amyloidosis.
- Other diseases. These include kidney disease, liver disease, connective tissue disorders and an underactive thyroid (hypothyroidism).
What are the Symptoms?
Every nerve in your peripheral system has a specific function. Therefore, symptoms depend on the type of nerves affected. Nerves have the following classifications:
- 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, heart rate, digestion and bladder
Signs and symptoms of peripheral neuropathy might include:
Gradual onset of numbness, prickling or tingling in your feet or hands, which can spread upward into your legs and arms
- Sharp, jabbing, throbbing, freezing or burning pain
- Extreme sensitivity to touch
- Lack of coordination and falling
- Muscle weakness or paralysis if motor nerves are affected
If autonomic nerves are affected, signs and symptoms might include:
- Heat intolerance and altered sweating
- Bowel, bladder or digestive problems
- Changes in blood pressure, causing dizziness or lightheadedness
Peripheral neuropathy can affect one nerve (mononeuropathy), two or more nerves in different areas (multiple mononeuropathy) or many nerves (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 offer the best chance for controlling your symptoms and preventing further damage to your peripheral nerves.
What are the Treatments?
The goals of treatment 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.
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 non-steroidal 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) 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 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 may include dry mouth, nausea, drowsiness, dizziness, decreased appetite and constipation.
A variety of therapies and procedures might help ease the signs and symptoms of peripheral neuropathy. For example:
- 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.
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.