Peripheral neuropathy is a result of damage to the nerves outside of the brain and spinal cord (peripheral nerves). It often causes weakness, numbness and pain, usually in your hands and feet and can also affect other areas of your body.
Your peripheral nervous system sends information from your brain and spinal cord (central nervous system) to the rest of your body. The peripheral nerves also send sensory information to the central nervous system. People with peripheral neuropathy generally describe the pain as stabbing, burning or tingling.
In many cases, symptoms improve, especially if caused by a treatable condition. Medications can reduce the pain of peripheral neuropathy.
One of the most common causes of this condition is diabetes.
Every nerve in your peripheral system has a specific function, so symptoms depend on the type of nerves affected. Nerves are classified into:
- Sensory nerves that receive sensation, such as temperature, pain, vibration or touch, from the skin
- Motor nerves that control muscle movement
- Autonomic nerves that control functions such as blood pressure, heart rate, digestion and bladder
Signs and symptoms of peripheral neuropathy might include:
- Muscle weakness.
- Sharp, jabbing, throbbing or burning pain.
- Extreme sensitivity to touch.
- Lack of coordination and falling.
- Paralysis if motor nerves are affected.
- Feeling as if you’re wearing gloves or socks when you’re not.
- Pain during activities that shouldn’t cause pain, such as pain in your feet when putting weight on them or when they’re under a blanket.
- Gradual onset of numbness, prickling or tingling in your feet or hands, which can spread upward into your legs and arms.
If autonomic nerves are affected, signs and symptoms might include:
- Heat intolerance
- Excessive sweating or not being able to sweat
- Bowel, bladder or digestive problems
- Changes in blood pressure, causing dizziness or lightheadedness
Peripheral neuropathy can affect one nerve (mononeuropathy), two or more nerves in different areas (multiple mononeuropathy) or many nerves (polyneuropathy). Carpal tunnel syndrome is an example of mononeuropathy. Most people with peripheral neuropathy have polyneuropathy.
Not a single disease, peripheral neuropathy is nerve damage caused by a number of conditions. Health conditions that can cause peripheral neuropathy include:
- Autoimmune diseases: These include Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and vasculitis.
- Diabetes: More than half the people with diabetes develop some type of neuropathy.
- Infections: These include certain viral or bacterial infections, including Lyme disease, shingles, Epstein-Barr virus, hepatitis B and C, leprosy, diphtheria, and HIV.
- Inherited disorders: Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathy. Growths, cancerous (malignant) and noncancerous (benign), can develop on the nerves or press nerves. Also, polyneuropathy can arise as a result of some cancers related to the body’s immune response. These are a form of a degenerative disorder called paraneoplastic syndrome.
- Bone marrow disorders: These include an abnormal protein in the blood (monoclonal gammopathies), a form of bone cancer (myeloma), lymphoma and the rare disease amyloidosis.
- Other diseases: These include kidney disease, liver disease, connective tissue disorders and an underactive thyroid (hypothyroidism).
Other causes include:
- Exposure to poisons: Toxic substances include industrial chemicals and heavy metals such as lead and mercury.
- Trauma or pressure on the nerve: Traumas, such as from motor vehicle accidents, falls or sports injuries, can sever or damage peripheral nerves. Nerve pressure can result from having a cast or using crutches or repeating a motion such as typing many times.
- Vitamin deficiencies: B vitamins — including B-1, B-6 and B-12 — vitamin E and niacin are crucial to nerve health.
- Poor dietary choices made by people with alcoholism can lead to vitamin deficiencies.
- Certain medications, especially those used to treat cancer (chemotherapy), can cause peripheral neuropathy.