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.

Peripheral Nerves of the Foot

Copyright © Nucleus Medical Media, Inc.

Causes

Many health conditions can cause peripheral neuropathy. The damage may the result of:

• Trauma from nerve compression or inflammation
• Certain medications, such as chemotherapy treatments for cancer
• Vitamin deficiencies
• Hereditary syndromes
• Exposure to toxins and heavy metals, such as lead, mercury, or pesticides
• Exposure to cold or radiation
• Prolonged treatment in the intensive care unit

Health conditions that can damage peripheral nerves include:

• Type 1 or type 2 diabetes
• Infections, such as Lyme disease, HIV, tuberculosis, or leprosy
• Chronic kidney failure
• Alcohol use disorder
• Autoimmune disorders, such as rheumatoid arthritis
• Acute or chronic demyelinating polyneuropathy
• Porphyria
• Paraneoplastic syndromes

Risk Factors

Having certain health conditions may increase your chance of getting peripheral neuropathy.

Symptoms

Damage to the peripheral nerves often results in sensory and motor symptoms in the:

• Arms
• Legs
• Hands
• Feet

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.

Peripheral neuropathy may cause:

• Numbness or reduced sensation
• Tingling
• Pain, often a burning or sharp, cutting sensation
• Sensitivity to touch
• Muscle twitches
• Muscle weakness
• 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
• Injuries to the feet that go unnoticed and become infected

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
• Difficulty breathing

Diagnosis

You will be asked 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
• Sensation in the feet using a fine flexible wire—Semmes-Weinstein monofilaments test

Additional tests may also include:

Tests of your bodily fluids and tissues:

• Blood tests, such as glucose, vitamin B12 level, and thyroid function tests
• Serum/urine electrophoresis
• Genetic testing
• Lumbar puncture
• Nerve fiber density skin biopsy
• Nerve or muscle biopsy

Evaluation of your nerves and muscles:

• Electromyography (EMG)
• Nerve conduction studies (NCS)

Imaging tests to evaluate nerves and other structures:

• MRI scan
• CT scan

Your doctor may need to evaluate other family members for this condition.

Treatment

Talk with your doctor about the best treatment plan for you. Options 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 pain medications are often used to ease discomfort. Botulinum toxin A injections may also be given to help reduce pain.

Medications used to treat depression and prevent convulsions can relieve neuropathy symptoms.

For severe and potentially life-threatening cases, such as Guillain-Barre syndrome, treatment includes:

• IV immunoglobulins
• Plasma exchange of the blood—plasmapheresis

Other Therapies

These therapies are aimed at reducing symptoms:

• Relaxation training
• Biofeedback
• Walking and other exercise
• Yoga
• Warm baths
• Massage
• Acupuncture
• Transcutaneous electronic nerve stimulation (TENS)

Surgery

Surgery can relieve the pressure on nerves. For example, surgeons commonly release fibrous bands in the wrist to treat carpal tunnel syndrome.

Prevention

To help reduce your chance of peripheral neuropathy:

• Manage chronic medical conditions with the help of your doctor. If you have diabetes, make sure you have regular foot exams.
• Eat a healthful diet that is low in saturated fat and rich in whole grains, fruits, and vegetables.
• Limit your alcohol intake to a moderate level. This means two or less drinks per day for men and one or less per day for women.
• Avoid toxic chemicals.