Mononeuropathy is damage to a single nerve or nerve group, which results in loss of movement, sensation, or other function of that nerve.
Neuropathy; Isolated mononeuritis
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 may cause isolated nerve damage.
Long-term pressure on a 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) may be damaged. This damage slows or prevents signals from traveling through the damaged 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 depend on the specific nerve affected, and may include:
Signs and tests
A detailed medical history is needed to determine the possible cause of the disorder. An examination and nerve and muscle testing may show a loss of feeling, movement, or other problems with a specific nerve. Reflexes may be abnormal.
Tests may include:
- Electromyogram (EMG) -- a recording of electrical activity in muscles
- Nerve conduction tests (NCV) -- recording the speed of electrical activity in the nerves
- Nerve biopsy
Other tests may include:
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.
- 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 duloxetine 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.
- Physical therapy exercises to maintain muscle strength
- Orthopedic braces, splints, or other appliances
- Vocational counseling, occupational therapy, occupational changes, job retraining
Mononeuropathy may be disabling and painful. If the cause of the nerve dysfunction can be found and successfully treated, a full recovery is possible and even likely in some cases.
The amount of disability varies from no disability to partial or complete loss of movement or sensation. Nerve pain may be uncomfortable and may last for a long time.
- Deformity, loss of tissue mass
- Medication side effects
- Repeated or unnoticed injury to the affected area due to lack of sensation
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.
Shy ME. Peripheral neuropathies. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 446.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and 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.