Reviewed By Sean O. Stitham MD, private practice in Internal Medicine, Seattle, Washington; and Danie…l B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.more »
Definition
Peripheral neuropathy is a problem with the nerves that carry information to and from the brain and spinal cord. This can produce pain, loss of sensation, and an inability to control muscles.
"Peripheral" means nerves further out from the center of the body, distant from the brain and spinal cord.
One set of peripheral nerves relay information from your central nervous system (brain and spinal cord) to muscles and other organs. A second set relays information from your skin, joints, and other organs back to your brain.
Peripheral neuropathy occurs when these nerves don't work properly, resulting in pain, loss of sensation, inability to control muscles, and other possible problems.
In some cases, the failure of nerves that control blood vessels, intestines, and other organs results in abnormal blood pressure, digestion problems, and loss of other basic body processes. Peripheral neuropathy may involve damage to a single nerve or nerve group (mononeuropathy) or may affect multiple nerves (polyneuropathy).
There are numerous reasons for nerves to malfunction. In many cases, no cause can be identified. Damage to nerves can result from:
Direct injury of the nerve either by hitting the nerve
Prolonged exposure to cold temperature
Prolonged pressure on the nerve (such as a long surgery or lengthy illness)
Peripheral neuropathy is very common. Because there are numerous types and causes of neuropathy and scientists don't always agree on the same definition of neuropathy, the exact incidence cannot be determined precisely.
Some people have a hereditary predisposition for neuropathy.
Symptoms
The symptoms depend on which type of nerve is affected. The three main types of nerves are:
Those that carry sensations (sensory)
Those that control muscles (motor)
Those that carry information to organs and glands (autonomic)
Neuropathy can affect any one or a combination of all three types of nerves. Symptoms also depend on whether the condition affects the whole body or just one nerve (as from an injury).
Longer nerves are more easily injured than shorter ones, so it is common for you to have worst symptoms in the legs and feet than in the hands and arms.
SENSATION CHANGES
Damage to sensory fibers results in changes in sensation, burning sensations, nerve pain, tingling or numbness, or an inability to determine joint position, which causes incoordination.
For many neuropathies, sensation changes often begin in the feet and progress toward the center of the body with involvement of other areas as the condition worsens. Diabetes is a common cause for sensory neuropathy.
MOVEMENT DIFFICULTIES
Damage to the motor fibers interferes with muscle control and can cause weakness, loss of muscle bulk, and loss of dexterity. Sometimes, cramps are a sign of motor nerve involvement.
Other muscle-related symptoms include:
Difficulty breathing or swallowing
Difficulty or inability to move a part of the body (paralysis)
Falling (from legs buckling or tripping over toes)
Lack of dexterity (such as being unable to button a shirt)
The autonomic nerves control involuntary or semi-voluntary functions, such as control of internal organs and blood pressure. Damage to autonomic nerves can cause:
A detailed history will be needed to determine the cause of the neuropathy. A neurological exam may reveal problems with movement, sensation, or organ function. Changes in reflexes and muscle bulk may also be present.
Tests for neuropathy are guided by the suspected cause of the disorder, as suggested by the history, symptoms, and pattern of symptom development. They may include various blood tests, x-rays, scans, or other tests and procedures.
Treatment
Treatmet involves:
Identifying and treating any underlying medical problem (such as diabetes) or removing the cause (such as alcohol)
Controlling symptoms
Curing the disorder, if possible
Helping the patient gain maximum independence and self-care ability
Physical therapy, occupational therapy, and orthopedic interventions may be recommended. For example, exercises and retraining may be used to increase muscle strength and control. Wheelchairs, braces, and splints may improve mobility or the ability to use an affected arm or leg.
Safety is an important consideration for people with neuropathy. Lack of muscle control and reduced sensation increase the risk of falls and other injuries. The person may not notice a potential source of injury because he or she can't feel it. For example, one may not notice if water in a bathtub is too hot. For this reason, people with decreased sensation should check their feet or other affected areas frequently for bruises, open skin areas, or other injuries, which may go unnoticed and become severely infected. Often, a podiatrist can determine if special orthotic devices are needed.
Safety measures for people experiencing difficulty with movement may include:
Installing railings
Removing obstacles on floors such as loose rugs
Safety measures for people having difficulty with sensation include:
Adequate lighting (including night lights)
Testing water temperature before bathing
Use of protective shoes (no open toes, no high heels)
Shoes should be checked often for grit or rough spots that may cause injury to the feet.
Persons with neuropathy (especially those with polyneuropathy or mononeuropathy multiplex) are prone to new nerve injury at pressure points such as knees and elbows. They should avoid prolonged pressure on these areas from leaning on the elbows, crossing the knees, or assuming similar positions.
Adjusting position, using frames to keep bedclothes off tender body parts, or other measures may also be helpful to reduce pain.
The symptoms of autonomic changes may be difficult to treat or respond poorly to treatment.
Use of elastic stockings and sleeping with the head elevated may help treat low blood pressure that occurs when standing up (postural hypotension). Fludrocortisone or similar medications may also be helpful.
Manual expression of urine (pressing over the bladder with the hands), intermittent catheterization, or medications such as bethanechol may be necessary for those with bladder dysfunction.
Impotence, diarrhea, constipation or other symptoms are treated as appropriate.
Support Groups
Additional information can be obtained from the Neuropathy Association - www.neuropathy.org
Expectations (prognosis)
The outcome greatly depends on the cause of the neuropathy. In cases where a medical condition can be identified and treated, the outlook may be excellent. However, in severe neuropathy, nerve damage can be permanent, even if the cause is treated appropriately.
For most hereditary neuropathies, there is no cure. Some of these conditions are harmless, while others progress more rapidly and may lead to permanent, severe complications.
Complications
The inability to feel or notice injuries can lead to infection or structural damage. Changes include poor healing, loss of tissue mass, tissue erosions, scarring, and deformity. Other complications include:
Recurrent or unnoticed injury to any part of the body
Calling your health care provider
Call your health care provider if symptoms of peripheral neuropathy are present. In all cases, early diagnosis and treatment increases the possibility that symptoms can be controlled.
Nerve pain, such as that caused by peripheral neuropathy, can be difficult to control. If pain is severe, contact a pain specialist may be able to suggest different approaches.
Emergency symptoms include irregular or rapid heartbeats, difficulty breathing, difficulty swallowing, and fainting.
Prevention
If a prolonged procedure or immobility is expected, appropriate measures (such as padding vulnerable areas) can be taken beforehand to reduce the risk of nerve problems.
Persons with a hereditary predisposition for neuropathy need to be especially careful to limit alcohol and manage other medical problems closely.
All people can reduce the risk of neuropathy by following a balanced diet, drinking alcohol in moderation, and maintaining good control of diabetes and other medical problems, if present.
