Peripheral neuropathy is failure of the nerves that carry information to and from the brain and spinal cord. This produces symptoms like pain, loss of sensation, and inability to control muscles.

("Neuro" = nerves, "pathy" = abnormal; "peripheral" = nerves beyond the brain and spinal cord.)

The peripheral nerves are responsible for relaying information from your central nervous system (brain and spinal cord) to muscles and other organs. Peripheral nerves also relay information back to your spinal cord and brain from your skin, joints, and other organs. Peripheral neuropathy occurs when these nerves fail to function properly, resulting in loss of sensation, pain, or inability to control muscles.

In some cases, failure of nerves controlling blood vessels, intestinal function, and other organs results in abnormal blood pressure, digestion, and loss of other basic involuntary processes. Peripheral neuropathy may involve damage to a single nerve or nerve group (mononeuropathy) or may affect multiple nerves (polyneuropathy).

There are numerous reasons why nerves may not function properly. In some cases, no cause can be identified. Damage to nerves can result from one of the specific conditions associated with neuropathy including:

• Hereditary disorders
  • Charcot-Marie-Tooth disease
  • Friedreich's ataxia
• Systemic or metabolic disorders
  • diabetes mellitus (diabetic neuropathy)
  • dietary deficiencies (especially vitamin B12)
  • excessive use of alcohol (alcoholic neuropathy)
  • uremia (from kidney failure)
  • Cancer
• Infectious or inflammatory conditions
  • AIDS
  • Hepatitis
  • botulism
  • Colorado tick fever
  • diphtheria
  • Guillain-Barre syndrome
  • HIV infection without development of AIDS
  • leprosy
  • Lyme
  • polyarteritis nodosa
  • rheumatoid arthritis
  • sarcoidosis
  • syphilis
  • systemic lupus erythematosus
  • amyloid
• Exposure to toxic compounds
  • sniffing glue or other toxic compounds
  • nitrous oxide
  • industrial agents--especially solvents
  • heavy metals (lead, arsenic, mercury, etc.)
• Neuropathy secondary to drugs (many drugs can cause neuropathy)
• Miscellaneous causes
  • ischemia (decreased oxygen/decreased blood flow)
  • prolonged exposure to cold temperature

Peripheral neuropathy is very common. Because there are numerous types and causes of neuropathy, the incidence varies greatly, depending on the type of neuropathy, geographic region, and many other factors. As scientists don't always agree on the same definition of neuropathy, the exact incidence can not be determined precisely.

Risk factors for neuropathy include diabetes, heavy alcohol use, and exposure to certain chemicals and drugs. Some people have a hereditary predisposition for neuropathy. Prolonged pressure on a nerve is another risk for developing a nerve injury. Pressure injury may be caused by prolonged immobility (such as a long surgical procedure or lengthy illness) or compression of a nerve by casts, splints, braces, crutches, or other devices.