What Triggers Neuropathy?

Neuropathy, or nerve pain, is caused by genetics or is acquired, such as from trauma, infection or an autoimmune disorder like diabetes.

Neuropathy describes conditions that involve damage to the nerves. Neuropathy may affect 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).

What Are Symptoms of Neuropathy?

Symptoms of 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 neuropathy 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

Symptoms of motor nerve damage include: 

• Muscle weakness
• Painful cramps
• Uncontrolled muscle twitching (fasciculations) 
• Muscle shrinking
• Sensory nerves are those that transmit sensory information such feelings of touch, temperature, or pain
  • 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
• Autonomic nerves are those that control the organs and regulate activities that are not consciously controlled, such as breathing, digestion, and heart function
  • Symptoms of autonomic nerve damage include:
    • Excess sweating
    • Heat intolerance
    • Inability to expand and contract the small blood vessels that regulate blood pressure
    • Gastrointestinal symptoms. 
    • Problems eating or swallowing (rare)

Neuropathy is caused by genetics or is acquired, such as from the result of another disorder or condition. In some cases, neuropathy has no known cause (idiopathic). 

Causes or triggers of symptomatic acquired neuropathy include:

• Physical injury (trauma)
• Diabetes 
• Vascular and blood problems such as diabetes, smoking, and narrowing of the arteries from high blood pressure (hypertension or atherosclerosis 
• Systemic autoimmune diseases such as lupus, rheumatoid arthritis, and Sjögren’s syndrome
• 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 (vitamin B12 deficiency and excess vitamin B6)
• Alcoholism
• Exposure to toxins 
• Certain cancers and benign tumors 
• Chemotherapy drugs and radiation therapy used to treat cancer
• Infections including varicella-zoster virus (which causes chickenpox and shingles), West Nile virus, cytomegalovirus, human immunodeficiency virus (HIV), herpes simplex, and Lyme disease

Neuropathies are diagnosed with a medical history, a physical exam, and a neurological exam. 

Tests used to diagnose 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) 

Treatment for 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, for example:

• 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
• Eating a balanced diet
• Not smoking 
• Correcting vitamin deficiencies
• Getting regular exercise 
• Avoiding toxic exposures

For motor symptoms of neuropathy, treatments may include: 

• Mechanical aids such as hand or foot braces to reduce physical disability and pain
• Orthopedic shoes or inserts 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 compressed nerve

For autonomic symptoms of neuropathy, treatments may include: 

• Complementary techniques such as 
• Acupuncture
• Massage
• Herbal preparations 
• Cognitive behavioral or other psychotherapy approaches 

For sensory symptoms of neuropathy, treatments may include:

• Behavioral strategies to cope with chronic pain, depression, and anxiety that may occur following nerve injury

Medications used to treat 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 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.

Some types of peripheral neuropathies may be prevented. 

• Mange blood sugar if you have diabetes
• People over 50 should receive the shingles vaccine to prevent shingles
• Avoid unnecessary medical procedures since medical procedures may damage nerves
• 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)