Peripheral neuropathy is damage to the peripheral nerves. These are the nerves that connect your spinal cord to the rest of your body.
Peripheral Nerves of the Foot
Many diseases and conditions can cause peripheral neuropathy. The damage may occur due to:
- Hereditary syndromes
- Unknown causes
Diseases that can damage peripheral nerves include (but are not limited to):
- Diabetes ( ]]>type 1]]> or ]]>type 2]]> )
- ]]>Lyme disease]]>
- ]]>Rheumatoid arthritis]]>
- Uremia from chronic ]]>kidney failure]]>
- Autoimmune disorders
- Viral infections (such as ]]>hepatitis]]> )
Compression commonly occurs when nerves are pinched or trapped somewhere along their course, such as:
- ]]>Carpal tunnel syndrome]]> (nerve in the wrist)
- ]]>Sciatica]]> (nerve roots forming the sciatic nerve in the back of the legs as they exit the spine)
Toxins that can damage the peripheral nerves include:
- Organic solvents (hexacarbons)
- Pesticides (organophosphates)
- Carbon disulfide
- ]]>Diphtheria]]> toxin
Many medicines can lead to peripheral neuropathy. A partial list includes:
- ]]>Chemotherapeutic agents]]> to treat cancer (eg, ]]>vincristine]]> , ]]>paclitaxel]]> , ]]>cisplatin]]> , suramin)
- Anti-HIV medications (eg, ]]>didanosine]]> , zalcitabine)
- Anti- ]]>tuberculosis]]> medications (eg, ]]>isoniazid]]> , ]]>ethambutol]]> )
- Other antimicrobial drugs (eg, ]]>dapsone]]> , ]]>metronidazole]]> , chloroquine, ]]>chloramphenicol]]> )
- Psychiatric medications (eg, ]]>lithium]]> )
- Other medications (eg, ]]>amiodarone]]> , aurothioglucose, ]]>phenytoin]]> , ]]>thalidomide]]> , ]]>colchicine]]> , ]]>cimetidine]]> , ]]>disulfiram]]> , ]]>hydralazine]]> , high levels of ]]>vitamin B6]]> )
Other causes of peripheral nerve damage include:
- Vitamin deficiencies ( ]]>thiamin]]> and ]]>B12 deficiency]]> , often related to alcoholism, and ]]>vitamin E]]> deficiency)
- A tumor pressing on a nerve
- Exposure to cold or radiation
- Acute or chronic demyelinating polyneuropathy
- Paraneoplatic syndromes
- Genetic disorders ( ]]>Charcot-Marie-Tooth disease]]> , Dejerine-Sottas disease, and Refsum’s disease)
- Prolonged treatment in the intensive care unit
These factors increase your chance of developing this condition. Tell your doctor if you have any of these risk factors:
- Diabetes (about 60% of people with diabetes have peripheral neuropathy)
- Alcohol abuse
- Autoimmune diseases, such as rheumatoid arthritis]]> or ]]>celiac sprue]]>
- Family member with peripheral neuropathy
- Exposure to toxins or medications known to cause neuropathy
- Vitamin deficiency (thiamin and vitamin B12)
- ]]>HIV infection]]>
- Pressure on a nerve (may occur with repetitive stress injuries)
- Hospitalization treatment in the intensive care unit
Damage to the peripheral nerves often results in sensory (feeling) and motor (strength) symptoms in the:
Other parts of the body can also be affected. Symptoms depend on which nerves are involved. They can range from mild to severe and may seem worse at night. Sensations and pain may occur in the upper or lower limbs and move toward the trunk (eg, from the feet to the calves).
- Numbness or reduced sensation
- Pain, often a burning or sharp, cutting sensation
- Sensitivity to touch
- Muscle twitches
- Muscle weakness
- Muscle cramping
- Difficulty with walking
- Loss of coordination or balance
If untreated, peripheral neuropathy can lead to:
- Loss of reflexes and muscle control
- Muscle atrophy (loss of muscle bulk)
- Foot deformities
- ]]>Foot ulcers]]>
- Injuries to the feet that go unnoticed and become infected
- Autonomic dysfunction (sweating, bowel and bladder dysfunction, cardiovascular effects)
- Difficulty breathing
The doctor will ask about your symptoms and medical history. She will also do a physical exam, which may include:
- Muscle strength
- Ability to feel vibration, temperature, and light touch
- Semmes-Weinstein monofilaments test—measures sensation in the feet using a fine flexible wire
Additional tests may also include:
- Blood tests (including glucose, vitamin B12 level, and thyroid function tests)
- Electromyography (EMG)]]> —measures and records electrical activity generated in muscle in response to nerve stimulation
- ]]>Nerve conduction studies (NCS)]]> —measures the speed and degree of electrical activity in a nerve to determine if it is functioning normally
- Serum/urine electrophoresis (protein analysis)
- Genetic testing
- Evaluation of family members
- ]]>Spinal tap]]> (lumbar puncture, LP)
- Nerve or muscle ]]>biopsy]]> (rarely)
Treatment may include:
Treatment for the Underlying Illness or Exposure
Treating the underlying illness can decrease or eliminate symptoms. For instance, if it is caused by diabetes, controlling blood sugar levels may help. In some cases, neuropathy caused by medications or toxins is completely reversed when these substances are stopped or avoided. Correction of vitamin B12 deficiency often improves symptoms.
Certain exercises may help stretch shortened or contracted muscles and increase joint flexibility. In long-standing cases, splinting the joint may be required to protect and rest it, while maintaining proper alignment.
Orthotics (supports and braces) may help with:
- Balance issues
- Muscle weakness
Maintaining physical activity is also key.
Prescription and over-the-counter (OTC) pain medicines are often used to ease discomfort.
Drugs to treat depression]]> and prevent convulsions sometimes relieve neuropathy symptoms. These medicines are often given at lower dosages. Commonly used antidepressants include:
- ]]>Amitriptyline]]> (Elavil)
- ]]>Nortriptyline]]> (Pamelor)
- ]]>Desipramine]]> (Norpramin)
- ]]>Imipramine]]> (Tofranil)
- ]]>Duloxetine]]> (Cymbalta)
Commonly used anticonvulsants may include:
- ]]>Gabapentin]]> (Neurontin)
- According to the Food and Drug Administration (FDA), patients of Asian ancestry who have a certain gene, called HLA-B*1502, and take carbamazepine are at risk for dangerous or even fatal skin reactions. If you are of Asian descent, the FDA recommends that you get tested for this gene before taking carbamazepine. If you have been taking this medication for a few months with no skin reactions, then you are at low risk of developing these reactions. Talk to your doctor before stopping this medication. ]]>*¹]]>
- ]]>Pregabalin]]> (Lyrica)—recently approved for peripheral neuropathy
For severe and potentially life-threatening cases (such as ]]>Guillain-Barre syndrome]]> ), treatment includes:
- Steroids (such as ]]>prednisone]]> )
- Intravenous immunoglobulins
These therapies are aimed at reducing symptoms and may include:
Surgery can relieve the pressure on nerves. For example, surgeons commonly release fibrous bands in the wrist to treat ]]>carpal tunnel syndrome]]> .
- Manage chronic medical conditions with the help of your doctor. If you have diabetes, visit a podiatrist for yearly exams.
- Eat a healthful diet]]> , one that is low in saturated fat and rich in whole grains, fruits, and vegetables.
- Be sure to get the right amounts of thiamin and vitamin B12.
- Limit your alcohol intake to a moderate level. This means two or fewer drinks per day for men and one or fewer for women.
- Toxic chemicals
- Repetitive movements
- Prolonged pressure on joints, especially elbows and knees
American Chronic Pain Association
The Neuropathy Association
Canadian Diabetes Association
Diabetic neuropathies: the nerve damage of diabetes. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health website. Available at: http://www.niddk.nih.gov/ .
Dyck PJ, Thomas PK, Dyck PJ, Thomas PK, eds. Peripheral Neuropathy . 4th ed. Philadelphia, PA: Saunders; 2004.
Fermaglich J. Merritt's Neurology . 11th ed. Chicago, IL: Lippincott Williams & Wilkins; 2005.
NINDS peripheral neuropathy information page. National Institute of Neurological Disorders and Stroke, National Institutes of Health website. Available at: http://www.ninds.nih.gov/ .
Peripheral neuropathy. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Accessed May 12, 2008.
Samuels MA, Feske SK. Office Practice of Neurology . Philadelphia, PA: Churchill Livingstone; 2003.
Williams O. Introduction to and clinical evaluation of peripheral neuropathies. In: Gilman S, ed. MedLink Neurology. San Diego, CA: MedLink Corporation.
12/20/2007 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : 2007 safety alerts for drugs, biologics, medical devices, and dietary supplements: Carbamazepine (marketed as Carbatrol, Equetro, Tegretol and generics). Medwatch. US Food and Drug Administration website. Available at: http://www.fda.gov/medwatch/safety/2007/safety07.htm#carbamazepine .
10/5/2009 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Feng Y, Schlösser FJ, Sumpio BE. The Semmes Weinstein monofilament examination as a screening tool for diabetic peripheral neuropathy. J Vasc Surg. 2009;50:675-682,682.
Last reviewed January 2010 by ]]>Rimas Lukas, MD]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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