What is neuropathy?
Neuropathy--also called peripheral neuropathy--refers
to any condition that affects the normal activity of the nerves of the
peripheral nervous system. The peripheral nervous system is the network of
nerves that connects the central nervous system--the brain and spinal cord--to
the rest of the body.
The peripheral nervous system is made up of three
types of nerves, each with an important role to play in keeping your body
healthy and functioning properly.
- Sensory nerves carry messages from your senses through your spinal
cord to your brain. For example, they tell your brain you are touching something hot.
- Motor nerves travel in the opposite direction. They carry messages
from the brain to your muscles. They tell your muscles to move you away from the hot surface.
- Autonomic nerves are responsible for controlling body functions that
occur outside our control, such as breathing, digestion, heart rate, and blood pressure.
Neuropathy results when nerve cells, or neurons, are
damaged or destroyed. This distorts the way the neurons communicate with each
other and with the brain. Neuropathy can affect one nerve or nerve type, or a combination of nerves.
What causes neuropathy?
There are many causes of neuropathy. The cause can be
hereditary (runs in families) or acquired (develops after birth).
The most common hereditary neuropathy is Charcot-Marie-Tooth
(CMT) disease, which affects both motor and sensory nerves. CMT affects about
one in 2,500 people in the United States. CMT causes weakness in the foot and
lower leg muscles. Deformities of the feet are also common, making it difficult
to walk and often resulting in falls. In its later stages, CMT can also affect
the muscles in the hands. There is no cure for hereditary neuropathy.
Acquired neuropathy is much more common. There are many causes of acquired neuropathy, including:
- Trauma — This includes sudden injury from an event such as a fall,
car accident or sports activity. Trauma to the peripheral nerves can also
occur from compression of the nerves due to repetitive stress or narrowing of the nerve space.
- Infections and autoimmune disorders — Among the germs that can
damage nerve fibers are human immunodeficiency virus (HIV), the herpes
virus, and the bacteria that cause Lyme disease and syphilis. Some
autoimmune disorders can also affect nerve tissue. Examples include
Guillain-Barré syndrome, systemic lupus erythematosus, and rheumatoid arthritis.
- Systemic diseases — Systemic diseases are those that affect the
entire body. These include diabetes--the leading cause of peripheral
neuropathy--kidney disorders, certain cancers, and hormonal imbalances.
- Medications and poisons — Some medicines, including the strong
medicines used to treat cancer (chemotherapy), can damage peripheral nerves.
Exposure to toxic substances such as heavy metals (including lead and
mercury) and industrial chemicals, especially solvents, can also affect nerve function.
- Vascular disorders — Neuropathy can occur when blood flow to
the arms and legs is hindered by inflammation, blood clots, or other blood
vessel disorders. Decreased blood flow deprives the nerve cells of oxygen,
causing nerve damage or nerve cell death.
- Vitamin imbalances — Proper levels of vitamins E, B1,
B6, B9, B12, and niacin are important for
healthy nerve function.
- Alcoholism — Excessive use of alcohol can rob the body of thiamine
and other essential nutrients, leading to neuropathy in the arms and legs.
When the cause of the neuropathy cannot be determined,
it is called idiopathic neuropathy. About 30 to 40 percent of neuropathy
cases are idiopathic. Another 30 percent are the result of diabetes.
How common is neuropathy?
Neuropathy is very common. It is estimated that about
25 percent to 30 percent of Americans will be affected by neuropathy. Neuropathy
occurs in 60 percent to 70 percent of people with diabetes.
Who gets neuropathy?
Neuropathy affects people of all ages; however, older
people are at increased risk. It is more common in men and in Caucasians. People
in certain professions, such as those that require repetitive motions, have a
greater chance of developing compression-related neuropathy.
What are the symptoms of neuropathy?
Symptoms of neuropathy vary depending on the type and
location of the nerves involved. Symptoms can appear suddenly, which is called
acute neuropathy, or develop slowly over time, called chronic neuropathy.
Common symptoms of sensory neuropathy include:
- Numbness, especially in the hands and feet
- Changes in sensation — Some people feel severe pain, especially at
night, and some are unable to feel pain, pressure, temperature, or touch.
- Loss of coordination
- Loss of reflexes
- Burning sensation
- Feeling that you are wearing socks or gloves when you are not
Common symptoms of motor neuropathy include:
- Muscle weakness
- Difficulty walking or moving your arms or legs
- Muscle twitching
- Loss of muscle control
- Loss of muscle tone
- Loss of dexterity
- Inability to move a part of the body
Common symptoms of autonomic neuropathy include:
- Abnormal blood pressure or heart rate
- Decreased sweating
- Problems with urination
- Sexual dysfunction
- Weight loss (unintentional)
- Dizziness when standing up or fainting
- Nausea or vomiting
- Problems with digestion
How is it diagnosed?
The first step in making a diagnosis is a thorough
history and physical examination. The information you provide can suggest to the
doctor which nerves or nerve groups are involved -- motor, sensory, autonomic or
a combination. Bloodwork and imaging tests can also provide information about a
possible cause of your neuropathy.
Your doctor might send you to a nerve specialist for an electrodiagnostic assessment (EDX) to find the location and degree
of nerve damage. EDX includes two tests:
- Nerve conduction study (NCS) — During this test, small
patches--called electrodes--are placed on the skin over nerves and muscles
on different parts of your body, usually your arms or legs. A brief pulse of
electricity is applied to the patch over a nerve to be studied. The doctor
measures the time it takes for the nerve to stimulate the muscles to twitch.
This is called the nerve conduction velocity, and it can tell if the nerve
is effectively controlling the muscle’s movement.
- Needle electromyography (EMG) — An EMG can determine the health of a
muscle by measuring its response to electrical activity. During an EMG, a
very thin needle electrode is inserted through the skin to stimulate the
muscle. The activity of the muscle is recorded on a graph called an electromyogram.
In some cases, a nerve, skin, or muscle biopsy is
needed to confirm the diagnosis. A biopsy is the removal of a small sample of
tissue for examination under a microscope.
How is neuropathy treated?
Treatment begins by identifying and treating any underlying medical problem, such as diabetes or infections.
Some cases of neuropathy, those that are hormonal or
nutrition-related, for example, can be easily treated and sometimes cured. In
most cases, however, neuropathy cannot be cured. Because neuropathy can have an
impact on quality of life, treatment is aimed at controlling and managing
symptoms. Treatment options include the following:
- Medicines can be used to control pain.
- Physical therapy uses a combination of focused exercise, massage and
other treatments to help you increase your strength, balance and range of motion.
- Occupational therapy can help you cope with the pain and loss of
function, and teach you skills to compensate for that loss.
- Surgery is available for patients with compression-related
neuropathy, such as carpal tunnel syndrome.
- Mechanical aids, such as braces and specially designed shoes, can
help reduce pain and allow for greater mobility.
- Proper nutrition involves eating a healthier diet and making sure to
get the right balance of vitamins and other nutrients.
- Adopting healthy living habits, including exercising to improve
muscle strength, quitting smoking, maintaining a healthy weight, and
limiting alcohol intake.
Can neuropathy be prevented?
You can reduce your risk by treating any medical
problems and adopting healthy living habits. If you have diabetes, it is
especially important that you manage your blood glucose level. Diet and
nutrition are also important for people with other disorders associated with neuropathy, such as kidney disease.
What is the outlook?
The overall outlook depends on the underlying cause of
the neuropathy. Neuropathy rarely leads to death if the cause is determined and
controlled. The sooner the diagnosis is made and treatment is started, the
greater the chance that nerve damage can be slowed or repaired. In most cases,
recovery takes a very long time. Some people live with a degree of neuropathy
for the rest of their lives.
When should I see my doctor?
If left untreated, peripheral neuropathy can lead to permanent nerve damage. It can also be a symptom of a serious disorder. It is
important to see your health care provider immediately as soon as you notice symptoms.
The Neuropathy Association, Inc., Neuropathy.
www.neuropathy.org Accessed 1/31/2011
National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Information Clearinghouse. Diabetic
Neuropathies: The Nerve Damage of Diabetes.
diabetes.niddk.nih.gov Accessed 1/31/2011
National Institute of Neurological Disorders and Stroke. Peripheral Neuropathy Information Page.
www.ninds.nih.gov Accessed 1/31/2011
© Copyright 1995-2011 The Cleveland Clinic Foundation. All rights reserved.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 11/18/2010…#14737