Radial nerve dysfunction

• Alternative Names

  Neuropathy - radial nerve ; Radial nerve palsy

• Causes, incidence, and risk factors

  Radial nerve dysfunction is a form of peripheral neuropathy. It occurs when there is damage to the radial nerve, which travels down the arm and controls movement of the triceps muscle at the back of the upper arm. It also controls extension of the wrist and helps in the movement and sensation of the wrist and hand.

  Dysfunction of a single nerve group (such as the radial nerve) is called mononeuropathy (mono means "one," and neuropathy means "nerve damage"). With mononeuropathy usually the nerve damage is caused locally. However, systemic disorders (such as mononeuritis multiplex) may occasionally cause nerve damage.

  Causes include:

  • Injury
    • "Crutch palsy," caused by improper use of crutches
    • Fracture of the humerus (upper arm bone)
    • Long-term or repeated constriction of the wrist (caused by wearing a tight watch strap, for example)
    • Pressure caused by hanging the arm over the back of a chair
    • Pressure to the upper arm from arm positions during sleep or coma
    • "Saturday-night palsy" (when the arm is in a position that pinches the nerve during deep sleep, such as when a person is intoxicated)
  • Long-term pressure on the nerve
  • Pressure on (compression of) the nerve caused by swelling or injury of nearby body structures

  These factors may be complicated by a lack of oxygen from decreased blood flow (ischemia) in the area.

  In some cases, no cause can be found.

• Symptoms

  Symptoms can affect the following:

  • Hand or forearm ("back" of the hand)
  • "Thumb side" (radial surface) of the dorsal hand
  • Fingers nearest the thumb (2nd and 3rd)

  The following symptoms may occur:

  • Abnormal sensations
  • Difficulty extending the arm at the elbow
  • Difficulty extending the wrist
  • Numbness, decreased sensation, tingling, or burning sensation
  • Pain
• Signs and tests

  The health care provider will take a history of your activities and injuries. An examination of the arm, hand, and wrist may identify radial nerve dysfunction.

  The exam may find:

  • Decreased ability to extend the arm at the elbow
  • Decreased ability to rotate the arm outward (supination)
  • Difficulty lifting the wrist or fingers (extensor muscle weakness)
  • Muscle loss (atrophy) in the forearm
  • Weakness of the wrist and finger
  • Wrist or finger drop

  In rare cases, it may be difficult to tell radial nerve dysfunction apart from a stroke.

  Tests for nerve dysfunction may include:

  • EMG
  • MRI of the head, neck, and shoulder
  • Nerve biopsy
  • Nerve conduction tests
• Treatment

  The goal of treatment is to maximize your ability to use the hand and arm. The health care provider should find and treat the cause appropriately. In most cases, no treatment is needed and you will recover slowly on your own.

  Surgery to remove masses that press on the nerve may help.

  CONTROL OF SYMPTOMS

  Medications may include:

  • Over-the-counter analgesics or prescription pain medications to control pain (neuralgia)
  • Phenytoin, carbamazepine, or tricyclic antidepressants (amitriptyline) to reduce stabbing pain
  • Steroids (prednisone) to reduce swelling

  Whenever possible, avoid or minimize your use of medications to reduce the risk of side effects.

  Other treatments include:

  • Braces, splints, or other appliances to help you use the hand in severe cases
  • Physical therapy to help maintain muscle strength

  Occupational therapy, or job counseling, changes, or retraining may be recommended as appropriate.

• Expectations (prognosis)

  If the cause of the nerve dysfunction can be found and successfully treated, there is a possibility that you will fully recover. Disability can range from none to partial or complete loss of movement or sensation.

  Nerve pain may be uncomfortable and may last for a long period of time. If this occurs, see a pain specialist to ensure you have access to all pain treatment options.

• Complications
  • Mild to severe deformity of the hand
  • Partial or complete loss of feeling in the hand
  • Partial or complete loss of wrist or hand movement
  • Recurrent or unnoticed injury to the hand
• Calling your health care provider

  Call your health care provider if you have had an injury to the arm, and you develop numbness, tingling, or weakness.

• Prevention

  The prevention varies depending on the cause. Avoid prolonged pressure on the upper arm.

Review Date: 9/22/2008

Reviewed By: Daniel 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.