Peripheral Neuropathy
Definition
Peripheral neuropathy is damage to the peripheral nerves. These are the nerves that connect your spinal cord to the rest of your body.
Causes
Many diseases and conditions can cause peripheral neuropathy. The damage may occur due to:
- Malnutrition
- Compression from repetitive stress
- Cancer
- Trauma
- Inflammation of nerves or blood vessels
- Infection
- Toxins
- Medications
- Hereditary syndromes
- Unknown causes
Diseases that can damage peripheral nerves include (but are not limited to):
Compression commonly occurs when nerves are pinched or trapped somewhere along their course, such as:
Toxins that can damage the peripheral nerves include:
Many medicines can lead to peripheral neuropathy. A partial list includes:
- Chemotherapeutic agents
to treat cancer, such as vincristine,
paclitaxel,
and cisplatin
- Anti-HIV medications, such as didanosine and
zalcitabine
-
Anti-
tuberculosis
medications, such as isoniazid and ethambutol
- Other antimicrobial drugs such as dapsone, metronidazole
, chloroquine,
and chloramphenicol
- Psychiatric medications, such as lithium
-
Other medications, such as
amiodarone, aurothioglucose,
phenytoin,
thalidomide,
colchicine,
cimetidine,
disulfiram,
hydralazine, and high levels of
vitamin B6
Other causes of peripheral nerve damage include:
-
Vitamin deficiencies, such as
thiamin
,
B12
, and
vitamin E
deficiency
- Injury
- A tumor pressing on a nerve
- Exposure to cold or radiation
- Leprosy
- Acute or chronic
demyelinating polyneuropathy
- Porphyria
- Paraneoplatic syndromes
-
Genetic disorders, such as
Charcot-Marie-Tooth disease
or hereditary motor and sensory neuropathy
- Prolonged treatment in the intensive care unit
Risk Factors
Factors that may increase your risk of getting peripheral neuropathy include:
- Diabetes
- 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, such as thiamin and vitamin B12
- HIV infection
- Pressure on a nerve—may occur with repetitive stress injuries
- Hospitalization treatment in the intensive care unit
Symptoms
Damage to the peripheral nerves often results in sensory and motor 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, such as from the feet to the calves.
Symptoms include:
- Numbness or reduced sensation
- Tingling
- 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
- Paralysis
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
If you have motor or sensory neuropathy, you may also have autonomic neuropathy. This is associated with symptoms such as:
- Problems regulating blood pressure
- Constipation
- Erectile dysfunction
Diagnosis
The doctor will ask about your symptoms and medical history. A physical exam will be done. It may include examining:
- Muscle strength
- Reflexes
- Balance
- Coordination
- 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:
-
You may need to have tests of your bodily fluids and tissues. This can be done with:
- Blood tests, such as glucose, vitamin B12 level, and thyroid function tests
- Serum/urine electrophoresis
- Genetic testing
- Spinal tap
, also called a lumbar puncture
-
Nerve or muscle
biopsy
—rarely
- Nerve fiber density skin biopsy
-
You may need to have your nerves and muscles tested. This can be done with:
-
You may need to have pictures taken of your bodily structures. This can be done with:
- Your doctor may need to evaluate other family members for this condition.
Treatment
Treatment may include:
Treatment for the Underlying Illness or Exposure
Treating the underlying illness can decrease symptoms or make them go away. 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 Therapy
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, such as supports and braces, may help with:
- Deformities
- Balance issues
- Muscle weakness
Maintaining physical activity is also important.
Medications
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
- Nortriptyline
- Desipramine
- Imipramine
- Duloxetine
Commonly used anticonvulsants may include:
- Gabapentin
-
Carbamazepine
- 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
For severe and potentially life-threatening cases, such as
Guillain-Barre syndrome
, treatment includes:
- IV immunoglobulins
- Plasmapheresis
—done to exchange plasma in the blood
Other Therapies
These therapies are aimed at reducing symptoms:
Surgery
Surgery can relieve the pressure on nerves. For example, surgeons commonly release fibrous bands in the wrist to treat
carpal tunnel syndrome.
Prevention
- Manage chronic medical conditions with the help of your doctor. If you have diabetes, visit a podiatrist for yearly exams.
-
Eat a
healthful diet
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.
-
Avoid:
- Toxic chemicals
- Repetitive movements
- Prolonged pressure on joints, especially elbows and knees
References
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Peripheral Neuropathy. 4th ed. Philadelphia, PA: Saunders; 2004.
Fermaglich J.
Merritt's Neurology. 11th ed. Chicago, IL: Lippincott Williams & Wilkins; 2005.
Karlsson P, et al. Epidermal nerve fiber length density estimation using global spatial sampling in healthy subjects and neuropathy patients.
J Neuropathol Exp Neurol. 2013 Mar;72(3):186-93.
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.
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