Axillary nerve dysfunction
DefinitionAxillary nerve dysfunction is nerve damage that leads to a loss of movement or sensation in the shoulder.
Alternative NamesNeuropathy - axillary nerve
Causes, incidence, and risk factorsAxillary nerve dysfunction is a form of peripheral neuropathy. It occurs when there is damage to the axillary nerve, which supplies the deltoid muscles of the shoulder and the skin around it. A problem with just one nerve, such as the axillary nerve, is called mononeuropathy.The usual causes are:Direct traumaLong-term pressure on the nervePressure on the nerve from nearby body structuresShoulder injuryEntrapment creates pressure on the nerve where it passes through a narrow structure.The damage may destroy the myelin sheath that covers the nerve, or part of the nerve cell (the axon). Damage of either type reduces or prevents the movement of impulses through the nerve.Conditions that can lead to axillary nerve dysfunction include:Body-wide (systemic) disorders that cause nerve inflammationDeep infectionFracture of the upper arm bone (humerus)Pressure from casts or splintsImproper use of crutchesShoulder dislocationIn some cases, no cause can be found.
SymptomsNumbness over part of the outer shoulderShoulder weakness, especially when lifting the arm up and away from the body
Signs and testsYour health care provider will examine your neck, arm, and shoulder. Weakness of the shoulder may cause difficulty moving your arm.The deltoid muscle of the shoulder may show signs of muscle atrophy.Tests that may be used to evaluate axillary nerve dysfunction include:EMG and nerve conduction tests -- will be normal right after the injury; should be performed several weeks after the injury or symptoms startMRI or x-rays of the shoulder
TreatmentDepending on the cause of the nerve disorder, some people do not need treatment. They will get better on their own. However, the rate of recovery can be different for everyone. It can take many months to recover.Anti-inflammatory medications may be given if you have:Sudden symptomsSmall changes in sensation or movementNo history of injury to the areaNo signs of nerve damageThese medicines reduce swelling and pressure on the nerve. They may be injected directly into the area or taken by mouth.Other medicines include:Over-the-counter pain medicines may be helpful for mild pain (neuralgia).Other medications (phenytoin, carbamazepine, gabapentin, pregabalin, duloxetine, or tricyclic antidepressants such as nortriptyline) may reduce the stabbing pains that some people experience.Opiate pain relievers, such as morphine or fentanyl, may be needed to control severe pain.Whenever possible, avoid or reduce medication use to lessen the risk of side effects.If your symptoms continue or get worse, you may need surgery. Surgery may be done to see if a trapped nerve is causing your symptoms. In this case, surgery to release the nerve may help you feel better.Physical therapy may help you maintain muscle strength. Job changes, muscle retraining, or other forms of therapy may be recommended.
Expectations (prognosis)It may be possible to make a full recovery if the cause of the axillary nerve dysfunction can be identified and successfully treated.
ComplicationsDeformity of the arm, shoulder contracture, or frozen shoulderPartial loss of sensation in the arm (uncommon)Partial shoulder paralysisRepeated injury to the arm
Calling your health care providerCall for an appointment with your health care provider if you have symptoms of axillary nerve dysfunction. Early diagnosis and treatment increase the chance of controlling symptoms.
PreventionPreventive measures vary, depending on the cause. Avoid putting pressure on the underarm area for a long period of time. Make sure casts, splints, and other appliances fit properly. When you use crutches, learn how to avoid putting pressure on the underarm.