Mononeuropathy

Definition

Mononeuropathy is damage to a single nerve or nerve group, which results in loss of movement, sensation, or other function of that nerve.

Alternative Names

Neuropathy - isolated

Causes, incidence, and risk factors

Mononeuropathy is a type of damage to nerves outside the brain and spinal cord (peripheral neuropathy).

Mononeuropathy is most often caused by injury, although body-wide (systemic) disorders (such as mononeuritis multiplex) may cause isolated nerve damage.

Long-term pressure on the nerve due to swelling or injury can result in mononeuropathy. The covering of the nerve (myelin sheath) or part of the nerve cell (the axon) is destroyed. This damage slows or prevents signals from traveling through the nerves.

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

• Axillary nerve dysfunction
• Common peroneal nerve dysfunction
• Carpal tunnel syndrome
• Cranial mononeuropathy III; compression type
• Cranial mononeuropathy III; diabetic type
• Cranial mononeuropathy VI
• Cranial mononeuropathy VII
• Femoral nerve dysfunction
• Radial nerve dysfunction
• Sciatic nerve dysfunction
• Ulnar nerve dysfunction

Symptoms

• Loss of bladder or bowel control
• Loss of sensation
• Numbness, decreased sensation
• Paralysis
• Tingling, burning, pain, abnormal sensations
• Weakness

Note: Symptoms are in only one part of the body.

Signs and tests

The health care provider will take a complete history, including any recent injury or exposure to toxins. Neuromuscular examination may show which nerve is involved. Reflexes may be abnormal in the area.

Tests may include:

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

Additional tests include:

• Antinuclear antibody panel (ANA)
• Blood tests
• C-reactive protein
• Imaging scans
• Rheumatoid factor
• Thyroid tests
• X-rays

Treatment

The goal of treatment is to allow you to use the affected body part as much as possible.

The cause of the mononeuropathy should be identified and treated as appropriate. Sometimes, no treatment is needed and you will get better on your own.

High blood pressure and diabetes can injure an artery, which can often affect a single nerve. The underlying condition should be treated.

Corticosteroids injected into the area may reduce swelling and pressure on the nerve if it is being pinched or trapped against another part of the body, such as a bone. Surgery may be recommended if symptoms are caused by entrapment of the nerve. Surgery to relieve the pressure on the nerve may help in some cases.

Medications:

• Over-the-counter or prescription pain medicine may be needed to control pain (neuralgia).
• Prescription medications such as gabapentin, pregabalin, phenytoin, carbamazepine, or antidepressants such as amitriptyline, nortriptyline, or duloxitine may be used to reduce stabbing pains. Whenever possible, avoid or minimize the use of these drugs to reduce the risk of medication side effects.

Other Treatments:

• Physical therapy exercises to maintain muscle strength
• Orthopedic braces, splints, or other appliances
• Vocational counseling, occupational therapy, occupational changes, job retraining

Expectations (prognosis)

Mononeuropathy may be disabling and painful. If the cause of the nerve dysfunction can be found 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 may last for a long time.

Complications

• Decreased self-esteem
• Medication side effects
• Mild to severe deformity
• Recurrent or unnoticed injury to the affected area due to lack of sensation

Prevention

Avoiding pressure or traumatic injury may prevent many forms of mononeuropathy. Treating conditions such as high blood pressure or diabetes also decreases your risk of developing the condition.