Polyneuropathy

Definition

Peripheral neuropathy, a result of damage to your peripheral nerves, often causes weakness, numbness and pain, usually in your hands and feet. It 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. Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes and exposure to toxins. One of the most common causes is diabetes mellitus.

People with peripheral neuropathy generally describe the pain as stabbing or burning. Often, there’s tingling. In many cases, symptoms improve, especially if caused by a treatable underlying condition. Medications can reduce the pain of peripheral neuropathy.

Symptoms

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 from the skin such as temperature, pain, vibration or touch
Motor nerves that control how your muscles move
Autonomic nerves that control functions such as blood pressure, heart rate, digestion and bladder

Signs and symptoms of peripheral neuropathy may include:

Gradual onset of numbness and tingling in your feet or hands, which may spread upward into your legs and arms
Sharp, jabbing or burning pain
Extreme sensitivity to touch
Lack of coordination and falling
Muscle weakness or paralysis if motor nerves are affected

If autonomic nerves are affected, signs and symptoms may include:

Heat intolerance and altered sweating
Bowel, bladder or digestive problems
Changes in blood pressure, causing dizziness or lightheadedness

Peripheral neuropathy may affect one nerve (mononeuropathy), two or more nerves in different areas (multiple mononeuropathy) or many nerves (polyneuropathy).

Causes

A number of factors can cause neuropathies, including:

Alcoholism. Poor dietary choices made by alcoholics can lead to vitamin deficiencies.
Autoimmune diseases. These include Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and necrotizing vasculitis.
Diabetes. More than half of people with diabetes develop some type of neuropathy.
Exposure to poisons.Toxic substances include heavy metals or chemicals.
Medications. Certain medications, especially those used to treat cancer (chemotherapy), may cause peripheral neuropathy.
Infections. These include certain viral or bacterial infections, including Lyme disease, shingles (varicella-zoster), Epstein-Barr virus, hepatitis C, leprosy, diphtheria and HIV.
Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathy.
Trauma or pressure on the nerve. Traumas, such as 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 many times, such as typing.
Tumors. Growths, cancerous (malignant) and noncancerous (benign), can develop on the nerves themselves or they can put pressure on surrounding nerves.
Vitamin deficiencies. B vitamins, including B-1, B-6 and B-12, vitamin E and niacin are crucial to nerve health.
Bone marrow disorders. These include abnormal protein in the blood (monoclonal gammopathies), a form of bone cancer (osteosclerotic myeloma), lymphoma and amyloidosis.
Other diseases. These include kidney disease, liver disease, connective tissue disorders and an underactive thyroid (hypothyroidism).

Risk factors

Peripheral neuropathy risk factors include:

Diabetes mellitus, especially if your sugar levels are poorly controlled
Alcohol abuse
Vitamin deficiencies, particularly B vitamins
Infections, such as Lyme disease, shingles (varicella-zoster), Epstein-Barr virus, hepatitis C and HIV
Autoimmune diseases, such as rheumatoid arthritis and lupus, in which your immune system attacks your own tissues
Kidney, liver or thyroid disorders
Exposure to toxins
Repetitive motion, such as those performed for certain jobs
Family history of neuropathy

Complications

Complications of peripheral neuropathy may include:

Burns and skin trauma.If parts of your body are numb, you may not feel temperature changes or pain.
Infection. Your feet and other areas lacking sensation can become injured without your knowing. Check these areas regularly and treat minor injuries before they become infected, especially if you have diabetes mellitus.

Neurology Conditions of the Brain, Spine & Nerves