Chapter 9

Medical Highlight: Peripheral Neuropathy

Peripheral neuropathy is the term used to describe damage to the peripheral nerves, the vast communication system that transmits messages from the brain and spinal cord to every part of the body. Additionally, the peripheral nervous system functions in part to control involuntary functions of the autonomic nervous system, which regulates internal organs, sweat glands, and blood pressure.

It is a frustrating and painful nerve condition that affects millions of Americans.

The most common form involves polyneuropathy, or damage to multiple nerves, and is frequently caused by diabetes. About half of people with diabetes develop some form of neuropathy but not all experience signs and symptoms. Other causes are uremia, AIDS, nutritional deficiencies, alcoholism, autoimmune diseases, reaction to certain medications, infections, and exposure to toxic substances. There is a form of neuropathy called entrapment caused by mechanical pressure. Carpal tunnel syndrome, a common example of entrapment neuropathy, is caused by the increase in repetitive motion tasks such as computer keyboarding. At other times no cause may be found.

Signs and symptoms often begin gradually. Sensorimotor neuropathy usually starts with numbness or tingling in the toes or the soles of the feet and symptoms slowly spread upward. It may also begin in the hands and extend up the arm. It may feel as if you are wearing an invisible glove or sock. There may be weakness, extreme sensitivity to touch, muscle weakness, loss of balance and coordination, burning or freezing pain, and accidental skin injury because of reduced pain perception.

Treatment is to manage the underlying condition, if possible. The goal is to slow or even repair the nerve damage and provide relief of the pain. If the case is a chronic condition such as diabetes controlling the blood sugar levels may improve the condition.

Medications for pain relief include:

  • Pain relievers such as aspirin and acetaminophen may be used to relieve mild symptoms. More severe pain calls for the use of prescription, nonsteroidal anti-inflammatory drugs.
  • Anti-seizure medications such as neurontin, dilantin, and tegretol (used to treat epilepsy) may be used.
  • Tricyclic antidepressants such as norpramin, tofranil, and pamelor are drugs that interfere with the chemical processes in the brain that cause a person to feel pain and may provide relief for mild to moderate symptoms.
  • Other drugs such as mexitil ordinarily used to treat irregular heart rhythm sometimes relieves the burning pain sensation.

Alternative therapies frequently used in conjunction with medications may include:

  • Transcutaneous electrical nerve stimulation (TENS) delivers tiny electrical impulses to specific nerve pathways through small electrodes placed on the skin.
  • Biofeedback therapy uses a specific machine to teach how to control certain body responses that reduce pain.
  • Other therapies that have been found effective in some cases include acupuncture, hypnosis, and relaxation techniques.

Health care techniques to manage the pain caused by peripheral neuropathy include:

  • Maintain proper foot care. Check daily for signs of blisters, cuts, or calluses. Provide the patient with well-fitting cotton socks and padded shoes. A semi-circular hoop can help to keep the bed covers off hot or sensitive feet.
  • Soak hands or feet in cool water for 15 minutes twice a day. After soaking apply a light coat of petroleum jelly to retain moisture and keep skin soft.
  • Massage the hands and feet to improve circulation and lessen discomfort as this may temporarily relieve pain.
  • Instruct the patient to remain active and move around as walking around may help relieve pain. Participation in activities may help to distract from the pain.
  • Encourage the patient to make lifestyle changes, e.g. reduce stress, eat balanced meals, and get regular exercise.
  • It is important to reduce stimulants such as caffeine and nicotine that restrict circulation.

Research for improved treatment includes:

  1. Aldose reductase inhibitors. This class of drugs has shown some promise in clinical trials.
  2. Antioxidants, such as alpha-lipoic acid, have shown significant effects on reducing pain in some trials.
  3. Nerve growth factors (these are synthetic forms of naturally produced chemicals) that signal the body to repair small nerve fibers. Thus far these have not been effective in clinical trials but some researchers think they may be an option.

References

National Institute of Neurological Disorders. (2005, March 8). NINDS peripheral

neuropathy information page. Retrieved March 10, 2005 from

Peripheral Neuropathy. (2004, September 9). Mayo clinic health letter22 (9), pgs. 1-2.