What is it?
Peripheral neuropathy describes damage to the peripheral nervous system, which transmits information from the brain and spinal cord to every other part of the body.
Impaired function and symptoms depend on the type of nerves -- motor, sensory or autonomic -- that are damaged. What are the symptoms?
Some people may experience temporary numbness, tingling, and pricking sensations, sensitivity to touch or muscle weakness. Others may suffer more extreme symptoms, including burning pain (especially at night), muscle wasting, paralysis, or organ or gland dysfunction. Peripheral neuropathy may be either inherited or acquired. What causes peripheral neuropathy?
Causes of acquired peripheral neuropathy include physical injury (trauma) to a nerve, tumors, toxins, autoimmune responses, nutritional deficiencies, alcoholism, and vascular and metabolic disorders. Acquired peripheral neuropathies are caused by systemic disease, trauma from external agents, or infections or autoimmune disorders affecting nerve tissue. Inherited forms of peripheral neuropathy are caused by inborn mistakes in the genetic code or by new genetic mutations. How is it diagnosed?
Diagnosing peripheral neuropathy is often difficult because the symptoms are highly variable. A thorough neurological examination is usually required and involves taking an extensive patient history, performing tests that may identify the cause of the neuropathic disorder, and conducting tests to determine the extent and type of nerve damage.
A general physical examination and blood tests are also conducted. An examination of cerebrospinal fluid that surrounds the brain and spinal cord can reveal abnormal antibodies associated with neuropathy. More specialized tests may reveal other blood or cardiovascular diseases, connective tissue disorders or malignancies. Tests of muscle strength, as well as evidence of cramps or fasciculations, indicate motor fiber involvement. Evaluation of a patient's ability to register vibration, light touch, body position, temperature, and pain reveals sensory nerve damage and may indicate whether small or large sensory nerve fibers are affected.
Based on the results of the neurological exam, physical exam, patient history, and any previous screening or testing, additional testing may be ordered to help determine the nature and extent of the neuropathy. Those tests could include CT scans, MRIs and electromyography (EMG). Nerve conduction velocity (NCV) tests can precisely measure the degree of damage in larger nerve fibers. Other tests include a nerve biopsy and skin biopsy .
Is there any treatment?
No medical treatments exist that can cure inherited peripheral neuropathy. However, there are therapies for many other forms.
In general, adopting healthy habits -- such as maintaining optimal weight, avoiding exposure to toxins, following a physician-supervised exercise program, eating a balanced diet, correcting vitamin deficiencies, and limiting or avoiding alcohol consumption -- can reduce the physical and emotional effects of peripheral neuropathy. Systemic diseases frequently require more complex treatments.
What research is being done?
The National Institute of Neurological Disorders and Stroke (NINDS) and other institutes of the National Institutes of Health (NIH) conduct research related to peripheral neuropathies in laboratories at the NIH and also support additional research through grants to major medical institutions across the country.
Current research projects funded by the NINDS involve investigations of genetic factors associated with hereditary neuropathies, studies of biological mechanisms involved in diabetes-associated neuropathies, and investigations exploring how the immune system contributes to peripheral nerve damage.
Neuropathic pain is a primary target of NINDS-sponsored studies aimed at developing more effective therapies for symptoms of peripheral neuropathy. Some scientists hope to identify substances that will block the brain chemicals that generate pain signals, while others are investigating the pathways by which pain signals reach the brain.
For more research information on peripheral neuropathy, see the National Institute of Neurological Disorders and Stroke Web site.
-- National Institute of Neurological Disorders and Stroke