Peripheral Neuropathy

How peripheral nerves work

Peripheral nerves contain three kinds of fibers:

• sensory fibers that carry touch, temperature, pain, vibration and position sense
• motor fibers that make muscles move
• autonomic fibers that control blood pressure, digestion, bladder, sweating and sexual function

Most neuropathies damage the longest nerves first, which is why symptoms begin in the toes.

Types of neuropathy

Symptoms

Sensory

• numbness or feeling as if wearing socks or gloves
• tingling, pins and needles
• burning, stabbing or electric pain, often worse at night
• extreme sensitivity to touch (even bedsheets hurt)
• reduced ability to feel temperature or injuries
• poor balance, especially in the dark

Motor

• weakness, tripping, and difficulty climbing stairs
• foot drop
• muscle cramps and twitching
• muscle wasting in the feet or hands

Autonomic

• dizziness on standing
• digestive and bladder problems
• abnormal sweating
• sexual dysfunction

Causes

Common causes

• Diabetes and prediabetes: the most common cause. Diabetic neuropathy affects up to half of people with long-standing diabetes.
• Alcohol: heavy long-term drinking damages nerves directly and through poor nutrition. See alcoholic neuropathy.
• Vitamin B12 deficiency: common in older adults, people on metformin or acid-suppressing medicines, and vegans. Too much vitamin B6 from supplements can also cause neuropathy.
• Medicines: chemotherapy (platinum drugs, taxanes, vincristine, bortezomib), some HIV drugs, metronidazole, nitrofurantoin, isoniazid, amiodarone and colchicine.
• Kidney failure and liver disease.
• Underactive thyroid.

Other causes

• Autoimmune and inflammatory: Guillain-Barré syndrome, CIDP, vasculitis, Sjögren's syndrome, lupus, rheumatoid arthritis, sarcoidosis, celiac disease
• Infections: HIV, hepatitis C, Lyme disease, shingles, leprosy
• Blood disorders: MGUS and paraproteinemic neuropathy, myeloma, amyloidosis
• Inherited: Charcot-Marie-Tooth disease, hereditary amyloidosis, Fabry disease
• Toxins: lead, arsenic, mercury, solvents
• Compression and injury
• Cancer (paraneoplastic)
• Idiopathic: in about a quarter to a third of people, no cause is found despite testing

Diagnosis

History and examination

Your doctor will ask about the pattern and speed of symptoms, diabetes, alcohol, medicines, diet, family history and other illnesses, and examine sensation (pinprick, vibration with a tuning fork, position sense), reflexes, strength, balance and the feet.

Tests

• blood tests: glucose and HbA1c (and sometimes a glucose tolerance test), B12 with methylmalonic acid, serum protein electrophoresis with immunofixation, kidney and liver function, thyroid function, and others as indicated
• nerve conduction studies and EMG: measure how well nerves conduct and whether damage is axonal or demyelinating
• skin biopsy: counts small nerve fibers when small fiber neuropathy is suspected
• autonomic testing
• genetic testing for inherited neuropathies
• nerve biopsy occasionally, for vasculitis or amyloid

Treatment

Treat the cause

• control blood sugar tightly in diabetes
• stop alcohol
• replace B12 or other vitamins
• adjust or stop medicines causing neuropathy, when possible
• treat thyroid, kidney or autoimmune disease
• immune treatments for Guillain-Barré, CIDP and vasculitic neuropathy

Nerve pain medicines

• gabapentinoids: pregabalin, gabapentin
• SNRIs: duloxetine, venlafaxine
• tricyclic antidepressants: amitriptyline, nortriptyline
• topical treatments: lidocaine patches, capsaicin cream or high-strength capsaicin patches

Standard painkillers often help little. Opioids are generally not recommended for long-term neuropathic pain. Spinal cord stimulation is an option for severe painful diabetic neuropathy that does not respond to medicines.

Physical therapy and safety

• balance and strength training to prevent falls
• ankle-foot orthoses for foot drop
• walking aids if needed
• good lighting and removing trip hazards at home

Foot care

Numb feet are prone to injuries that go unnoticed:

• check your feet every day for cuts, blisters, redness or swelling
• wear well-fitting shoes and socks, and never walk barefoot
• test bath water with your elbow or a thermometer
• keep skin moisturized, but not between the toes
• see a podiatrist for nails and calluses, and have a foot exam at least yearly if you have diabetes

Outlook

Outlook depends on the cause. Neuropathy from B12 deficiency, medicines or treatable autoimmune conditions can improve. Diabetic and many other neuropathies usually cannot be reversed, but progression can be slowed, and symptoms well managed. Complications include falls, foot ulcers, infections and, rarely, amputation, which are largely preventable.

Frequently asked questions

What are the first signs of peripheral neuropathy?

Early signs are usually numbness, tingling, or burning in the toes and feet, often worse at night. Some people notice reduced feeling, cramps, or poor balance. Symptoms typically start in both feet and slowly move upward.

What is the most common cause of peripheral neuropathy?

Diabetes is the most common cause. Other common causes are heavy alcohol use, vitamin B12 deficiency, certain medicines including chemotherapy, kidney disease and an underactive thyroid. In many people no cause is found.

Can peripheral neuropathy be reversed?

Sometimes. Neuropathy from vitamin deficiency, certain medicines, or treatable inflammatory conditions can improve if caught early. Diabetic neuropathy usually cannot be reversed, but good blood sugar control can slow it and treatments ease symptoms.

What is the best treatment for neuropathy pain?

Medicines specifically for nerve pain, such as pregabalin, gabapentin, duloxetine or amitriptyline, work best. Lidocaine and capsaicin patches help some people. Regular painkillers and opioids are less effective and not recommended long-term.

Is walking good for peripheral neuropathy?

Yes. Regular walking and exercise improve balance, strength, blood flow and blood sugar control, and may reduce pain. Wear well-fitting shoes, check your feet afterward, and consider balance training with a physical therapist.