Many of the diseases of the peripheral nervous system may present similarly to muscle problems (myopathies), and so it is important to develop approaches for assessing sensory and motor disturbances in patients so that a physician may make an accurate diagnosis.
Peripheral neuropathies may either be symmetrical and generalized or focal and multifocal, which is usually a good indicator of the cause of the peripheral nerve disease.
Generalized peripheral neuropathy
Generalized peripheral neuropathies are symmetrical, and usually due to various systematic illnesses and disease processes that affect the peripheral nervous system in its entirety.
They are further subdivided into several categories:
Those with diseases or dysfunctions of their peripheral nerves can present with problems in any of the normal peripheral nerve functions.
In terms of sensory function, there are commonly loss of function (negative) symptoms, which include numbness, tremor, and gait imbalance.
Gain of function (positive) symptoms include tingling, pain, itching, crawling, and pins and needles. Pain can become intense enough to require use of opiate drugs (i.e., morphine, oxycodone).
Skin can become so hypersensitive that patients are prohibited from having anything touch certain parts of their body, especially the feet. People with this degree of sensitivity cannot have a bedsheet touch their feet or wear socks or shoes, and eventually become housebound.
Motor symptoms include loss of function (negative) symptoms of weakness, tiredness, heaviness, and gait abnormalities; and gain of function (positive) symptoms of cramps, tremor, and fasciculations.
There is also pain in the muscles (myalgia), cramps, etc., and there may also be autonomic dysfunction.
During physical examination, those with generalized peripheral neuropathies most commonly have distal sensory or motor and sensory loss, though those with a pathology (problem) of the peripheral nerves may be perfectly normal; may show proximal weakness, as in some inflammatory neuropathies like Guillain-Barré syndrome); or may show focal sensory disturbance or weakness, such as in mononeuropathies, radiculopathies and plexopathies.
Many treatment strategies for peripheral neuropathy are symptomatic. Some current research in animal models has shown that neurotrophin-3 can oppose the demyelination present in some peripheral neuropathies.
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^ Kiziltan ME, Akalin MA, Sahin R, Uluduz D (2007). "Peripheral neuropathy in patients with diabetes mellitus presenting as Bell's palsy". doi:10.1016/j.neulet.2007.09.029. PMID 17933462.
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^ Wilkes G (2007). "Peripheral neuropathy related to chemotherapy". Seminars in oncology nursing23 (3): 162–73. doi:10.1016/j.soncn.2007.05.001. PMID 17693343.
^ Liu N, Varma S, Tsao D, Shooter EM, Tolwani RJ (2007). "Depleting endogenous neurotrophin-3 enhances myelin formation in the Trembler-J mouse, a model of a peripheral neuropathy". J. Neurosci. Res.85 (13): 2863–9. doi:10.1002/jnr.21388. PMID 17628499.
Dr. Lee Dellon: Pioneering Pain Relief Dr. Lee Dellon's research in the pain caused by Peripheral Neuropathy and other nerve disorders is highlighted in this recent article.
Diseases of the peripheral system[dead link – history] - These lecture notes were presented to a second year medical school class at the University of Western Ontario on 2 December 2004 by Dr. Angelika F. Hahn.
Approach to Muscle and nerve problems[dead link] - Powerpoint slides from a lecture presented to a second year medical school class at the University of Western Ontario on 2 December 2004 by Dr. Michael W. Nicolle.