Alternate Names: Neuropathy - isolated

Causes and Risks:

Mononeuropathy involves damage or destruction of an isolated nerve or nerve group. It is a type of peripheral neuropathy (damage to nerves other than the nerves of the brain and spinal cord).

Mononeuropathy most commonly is associated with local causes of nerve damage such as trauma, although occasionally systemic disorders may cause isolated nerve damage (such as occurs with mononeuritis multiplex). The usual causes are direct trauma, prolonged pressure on the nerve, and compression of the nerve from nearby body structures.

The damage includes destruction of the myelin sheath (covering) of the nerve or of part of the nerve cell (the axon). This damage slows or prevents conduction of impulses through the nerve.

Mononeuropathy may involve any part of the body. Some of the common forms of mononeuropathy include:

• Sciatic nerve dysfunction
• Common peroneal nerve dysfunction
• Radial nerve dysfunction
• Ulnar nerve dysfunction
• Cranial mononeuropathy VI
• Cranial mononeuropathy VII
• Cranial mononeuropathy III; compression type
• Cranial mononeuropathy III; diabetic type
• Axillary nerve dysfunction
• Distal median nerve dysfunction
• Femoral nerve dysfunction
• Tibial nerve dysfunction

Prevention: Avoiding pressure or traumatic injury may prevent many forms of mononeuropathy.

Symptoms:

• Impairment of sensation
  • Numbness, decreased sensation
  • Tingling, burning, pain, abnormal sensations
  • Loss of sensation
• Impairment of movement
  • Weakness
  • Paralysis (total loss of movement)

Signs and Tests: Neuromuscular examination of the affected area may indicate which nerve is involved in the mononeuropathy. Reflexes may be abnormal in the area. Symptoms are isolated to one nerve area.

Tests for mononeuropathy may include:

• EMG (a recording of electrical activity in muscles)
• Nerve conduction tests
• Nerve biopsy

Treatment: Treatment is aimed at maximizing the ability to use the affected body part. The cause should be identified and treated as appropriate. In some cases, no treatment is required and recovery is spontaneous.

If there is no history of trauma to the area, conservative treatment is indicated by sudden onset, minimal sensation changes, no difficulty in movement, and no test results indicating degeneration of the nerve axon.

Corticosteroids injected into the area may reduce swelling and pressure on the nerve in some cases. Surgical intervention is indicated if the symptoms are from entrapment of the nerve. Surgical removal of lesions that press on the nerve may benefit some cases.

Control of Symptoms:
Over-the-counter analgesics or prescription pain medications may be needed to control pain (neuralgia). Various other medications may reduce the stabbing pains that some people experience, including gabapentin, phenytoin, carbamazepine, or tricyclic antidepressants (such as amitriptyline). Whenever possible, their use should be avoided or minimized to reduce the risk of medication side effects.

Physical therapy exercises may be appropriate for some people to maintain muscle strength. Orthopedic assistance may maximize the ability to use the affected body part. This may include the use of braces, splints, or other appliances.

Vocational counseling, occupational therapy, occupational changes, job retraining, or similar interventions may be recommended.

Prognosis:

Mononeuropathy is rarely fatal, but it may be disabling and painful. If the cause of the nerve dysfunction can be identified and successfully treated, there is a possibility of full recovery.

The extent of disability varies from no disability, to partial or complete loss of movement or sensation. Nerve pain may be quite uncomfortable and persist for a prolonged period of time.

Complications:

• Recurrent or unnoticed injury to the affected area
• Deformity, mild to severe
• Decreased self esteem

Call your health care provider if symptoms of nerve dysfunction are present. Early diagnosis and treatment increase the chance of controlling symptoms.