What Is Peripheral Neuropathy?
Peripheral neuropathy describes conditions that involve damage to the peripheral nerves, which are the nerves beyond the brain and spinal cord. Neuropathy may involve damage to only one nerve (mononeuropathy), two or more nerves in different areas (multiple mononeuropathy or mononeuropathy multiplex), or may affect many or most of the nerves (polyneuropathy).
There are more than 100 types of peripheral neuropathy and symptoms vary depending on the type of nerves that are damaged:
- Motor nerves are those that control the movement of the muscles under conscious control, such as those used for walking, gripping objects, or talking
- Sensory nerves are those that transmit sensory information such feelings of touch, temperature, or pain
- Autonomic nerves are those that control the organs and regulate activities that are not consciously controlled, such as breathing, digestion, and heart function
What Are Symptoms of Peripheral Neuropathy?
Symptoms of peripheral neuropathy can range from mild to disabling and depend on the type of nerve fibers affected and the type and severity of damage. Symptoms can develop over days, weeks, or years.
Symptoms of motor nerve damage include:
- Muscle weakness
- Painful cramps
- Uncontrolled muscle twitching (fasciculations)
- Muscle shrinking
Symptoms of sensory nerve damage include:
- Diminished ability to feel vibrations and touch, especially in the hands and feet
- Loss of reflexes
- Loss of position sense
- Diminished ability to feel pain or changes in temperature.
Symptoms of autonomic nerve damage include:
What Causes Peripheral Neuropathy?
Peripheral neuropathy is caused by genetics or is acquired, such as from the result of another disorder or condition. In some cases, peripheral neuropathy has no known cause (idiopathic).
Causes of symptomatic acquired peripheral neuropathy include:
- Physical injury (trauma) such as from automobile accidents, falls, sports, and medical procedures
- Vascular and blood problems such as diabetes, smoking, and narrowing of the arteries from high blood pressure or atherosclerosis
- Systemic autoimmune diseases such as Sjögren’s syndrome, lupus, and rheumatoid arthritis
- Autoimmune diseases that attack nerves only such as Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy
- Hormonal imbalances
- Kidney and liver disorders
- Nutritional or vitamin imbalances (such as vitamin B12 deficiency and excess vitamin B6), alcoholism, and exposure to toxins
- Certain cancers and benign tumors
- Chemotherapy drugs used to treat cancer as well as radiation therapy
- Infections including viruses such as varicella-zoster virus (which causes chicken pox and shingles), West Nile virus, cytomegalovirus, human immunodeficiency virus (HIV), and herpes simplex, and Lyme disease
How Is Peripheral Neuropathy Diagnosed?
Peripheral neuropathy is diagnosed with a medical history and a physical and neurological exam.
Tests that may be used to diagnose peripheral neuropathy may also include:
- Blood tests for diabetes, vitamin deficiencies, liver or kidney dysfunction, other metabolic disorders, infections and signs of abnormal immune system activity
- Other body fluids may be tested for abnormal proteins or the abnormal presence of immune cells or proteins
- Genetic tests
- Nerve conduction velocity (NCV) tests
- Electromyography (EMG)
- Nerve biopsy
- Neurodiagnostic skin biopsy
- Autonomic testing, such as a QSART
- Magnetic resonance imaging (MRI) of the spine or nerve
- Computed tomography (CT) scans of the back
- Muscle and nerve ultrasound (experimental)
What Is the Treatment for Peripheral Neuropathy?
Treatment for peripheral neuropathy depends on the type of nerve damage, symptoms, and location.
Treating the underlying cause of the neuropathy can cause it to go away on its own, such as:
- Controlling blood sugar in patients who have diabetes
- Controlling inflammatory and autoimmune conditions that can cause neuropathy
Lifestyle changes that can help nerves recover and regenerate include:
- Maintaining a healthy weight
- Avoiding toxic exposures
- Eating a balanced diet
- Correcting vitamin deficiencies
- Not smoking
- Getting regular exercise
For motor symptoms of peripheral neuropathy, treatments may include:
- Mechanical aids such as hand or foot braces to reduce physical disability and pain
- Orthopedic shoes to improve gait disturbances and prevent foot injuries
- Splints for carpal tunnel syndrome
- In severe cases, tendon transfers or bone fusions to hold the limbs in better position or to release a nerve compression.
For autonomic symptoms of peripheral neuropathy, treatments may include:
- Complementary methods and techniques such as
- Herbal preparations
- Cognitive behavioral or other psychotherapy approaches
For sensory symptoms of peripheral neuropathy, treatments may include:
- Behavioral strategies to cope with chronic pain, depression, and anxiety that may occur following nerve injury
Medications used to treat peripheral neuropathic pain are also used for other medical conditions and may include:
- Antidepressants including nortriptyline and serotonin-norepinephrine reuptake inhibitors (SNRIs) such as duloxetine hydrochloride
- Epilepsy medications such as gabapentin, pregabalin, topiramate, lamotrigine, carbamazepine, and oxcarbazepine
- Local anesthetics and related drugs that block nerve conduction
- Lidocaine patches or creams
- Topical capsaicin
- Lidocaine or longer acting bupivicaine administered using implanted pumps to deliver tiny quantities to spinal cord fluid
- Narcotics (opioids) for pain that doesn’t respond to other pain-control medications
Surgery may be recommended to treat some types of neuropathies such as:
- Protruding disks (“pinched nerves”) in the back or neck
- Trigeminal neuralgia on the face
- Injuries to a single nerve (mononeuropathy) caused by compression, entrapment, or rarely tumors or infections
Transcutaneous electrical nerve stimulation (TENS) is a treatment that involves attaching electrodes to the skin at the site of pain or near associated nerves and then administering a gentle electrical current. TENS may improve neuropathic symptoms associated with diabetes.
How Do You Prevent Peripheral Neuropathy?
Some types of peripheral neuropathies may be prevented.
- Avoid unnecessary medical procedures since medical procedures may damage nerves
- People over 50 should receive the shingles vaccine to prevent shingles
- Mange blood sugar if you have diabetes
- If you have neuropathy, talk to your doctor about use of medications that can worsen symptoms
- Never stop taking a prescribed medication without first talking to your doctor