Peripheral Neuropathy

Chemotherapeutic agents to treat cancer ( vincristine , paclitaxel , cisplatin , suramin) Anti-HIV medications ( didanosine , zalcitabine ) Anti-tuberculosis medications ( isoniazid , ethambutol ) Other antimicrobial drugs ( dapsone , metronidazole , chloroquine, chloramphenicol ) Psychiatric medications ( lithium ) Other medications ( 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)InjuryA tumor pressing on a nerveExposure to cold or radiationLeprosyAcute or chronic demyelinating polyneuropathyPorphyriaParaneoplatic syndromes Genetic disorders ( Charcot-Marie-Tooth disease, Dejerine-Sottas disease, and Refsums disease) Prolonged treatment in the intensive care unit (usually associated with having a tube inserted for a long time and taking medications that paralyze muscles) Risk Factors A risk factor is something that increases your chance of getting a disease or condition.Risk factors for peripheral neuropathy include:

Diabetes (about 60% of people with diabetes have peripheral neuropathy) Alcohol abuse Autoimmune diseases, such as rheumatoid arthritis or celiac sprueFamily member with peripheral neuropathyExposure to toxins or medications known to cause neuropathyVitamin deficiency (thiamin and vitamin B12)HIV infectionPressure on a nerve (may occur with repetitive stress injuries) Hospitalization treatment in the intensive care unit SymptomsDamage to the peripheral nerves often results in sensory (feeling) and motor (strength) symptoms in the arms, legs, hands, and feet. However, it can affect any part of the body. Symptoms vary, depending on which nerves are involved.Symptoms may 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). Symptoms include: Numbness or reduced sensationTinglingPain, often a burning or sharp, cutting sensationSensitivity to touchMuscle twitchesMuscle weaknessMuscle crampingDifficulty with walkingLoss of coordination or balance Paralysis If untreated, peripheral neuropathy can lead to: Loss of reflexes and muscle controlMuscle atrophy (loss of muscle bulk)Foot deformitiesFoot ulcersInjuries to the feet that go unnoticed and become infectedAutonomic dysfunction (sweating, bowel and bladder dysfunction, cardiovascular effects) Difficulty breathing Diagnosis The doctor will ask about your symptoms and medical history, and perform a physical exam. The physical exam will include tests of:

Muscle strengthReflexesBalanceCoordinationAbility to feel vibration, temperature, and light touch Additional tests may also include: Blood tests (including glucose, vitamin B12 level, and thyroid function tests)Electromyography (EMG)measurement and recording of electrical activity generated in muscle in response to a nervous stimulation Nerve conduction studies Nerve or muscle biopsy (rarely) Evaluation of family membersGenetic testingSerum/urine electrophoresis (protein evaluation)Spinal tap for demyelinating disorders TreatmentTreatment may include: Treatment for the Underlying Illness or ExposureTreating 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. Physical TherapyCertain 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.

Patients may also benefit from orthotics (supports and braces) to help with deformities, balance issues, and muscle weakness. Maintaining physical activity is also key. MedicationsPrescription and over-the-counter (OTC) pain medications are often used to ease discomfort. Drugs to treat depression and prevent convulsions sometimes relieve neuropathy symptoms. These medications are often given at lower dosages than those prescribed for depression and seizures . Commonly used antidepressants include: Amitriptyline (Elavil) Nortriptyline (Pamelor) Desipramine (Norpramin) Imipramine (Tofranil) Commonly used anticonvulsants may include:Gabapentin (Neurontin) Carbamazepine (Tegretol) 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. *Pregabalin (Lyrica)recently approved for peripheral neuropathy Some peripheral neuropathies that are severe and potentially life-threatening (such as Guillain-Barre syndrome ) require treatment with steroids (such as prednisone ) and intravenous immunoglobulins.

Other Therapies These therapies are aimed at reducing symptoms and may include: Relaxation trainingBiofeedbackWalkingExerciseYogaWarm bathsMassageAcupunctureTranscutaneous electronic nerve stimulation Surgery Surgery can relieve the pressure on nerves. For example, surgeons commonly release fibrous bands in the wrist to treat carpal tunnel syndrome . PreventionManage chronic medical conditions with the help of your doctor. If you have diabetes, you should 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 recommended amounts of thiamin and vitamin B12.Limit your alcohol intake to a moderate level. Moderate is two or fewer drinks per day for men and one or fewer for women and older adultsAvoid: Toxic chemicalsRepetitive movementsProlonged pressure on joints, especially elbows and knees RESOURCES: American Chronic Pain Associationhttp://www.theacpa.org The Neuropathy Associationhttp://www.neuropathy.org CANADIAN RESOURCES: Canadian Diabetes Associationhttp://www.diabetes.ca Team Diabetes CanadaCanadian Diabetes Associationhttp://www.diabetes.ca/section_donations/TeamDiabetesIndex.asp

References: Dyck PJ, Thomas PK, Dyck PJ, Thomas PK, eds. Peripheral Neuropathy . 4th ed. Saunders; 2004. Merritt's Neurology . 11th ed. Lippincott Williams & Wilkins; 2005. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health website. Available at: http://www.niddk.nih.gov/ . 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. Medlink website. Available at: http://www.medlink.com. Accessed May 12, 2008. *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 .

Last reviewed March 2008 by J. Thomas Megerian, MD, PhD, FAAPPlease 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.