Brachial plexus dysfunction (brachial plexopathy) is a form of peripheral neuropathy. It occurs when there is damage to the brachial plexus, an area where a nerve bundle from the spinal cord splits into the individual arm nerves.

Damage to the brachial plexus is usually related to direct trauma to the nerve, stretch injury (such as rapid jerking of the arm), pressure caused by tumors in the area of the brachial plexus and damage that results from radiation therapy (therapy for some forms of cancer, such as lung cancer).

It may be related to pressure caused by congenital abnormalities that affect the cervical ribs and can also sometimes be associated with exposure to toxins, chemicals, or drugs.

Rarely, it is caused by an inflammatory condition. In some cases, no cause can be identified. The mechanical factors (pressure) may be complicated by ischemia (lack of oxygen caused by decreased blood flow) in the area.

• Shoulder pain.
• Numbness of the shoulder, arm, or hand.
• Tingling, burning, pain, abnormal sensations.
  • The location varies with the part of the plexus injured.
• Weakness (decreased muscle strength, independent of exercise) of the arm, hand, or wrist.
  • Unable to extend or lift the wrist (wrist drop).
  • Hand weakness.
• If caused by a lung tumor compressing the plexus, there may be associated Horner's syndrome (eye drooping and decreased sweating in the face and small pupil).

Neuromuscular examination of the arm, hand, and wrist indicates brachial plexus dysfunction. Reflexes may be abnormal in the arm. Specific muscle losses may indicate the portion of the brachial plexus that has been damaged.

Variable deformities may develop in the arm or hand, and loss of muscle mass (atrophy) may be profound. Detailed history may be needed to determine the possible cause of the problem.

Tests that reveal brachial plexopathy may include:

• Nerve conduction test and electromyography (NCS/EMG), which is a recording of the electrical activity of nerves and muscles.
• Nerve biopsy -- indicating systemic diseases that may affect the brachial plexus.

Treatment is aimed at maximizing independence. 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 may be tried for patients who experienced sudden onset of symptoms, minimal sensation changes, no movement difficulties, and no evidence of nerve fiber loss on NCS/EMG.

Potent anti-inflamatory drugs (called steroids) may be recommended for cases that are caused by inflammatory lesions (such as brachial amyotrophy and brachial neuritis).

Surgery may be necessary if the disorder is long lasting, symptoms worsen, difficulty with movement is profound, or if there is evidence of nerve fiber loss. Surgical "decompression" (surgical removal of lesions that press on the nerve) may help some patients.

Common painkillers, like acetaminophen, aspirin, and ibuprofen may be insufficient to control pain (neuralgia). Various other medications may be used to reduce the stabbing pains that some people experience, including antiseizure medications (such as phenytoin, carbamazepine, and gabapentin). Tricyclic antidepressants, such as amitriptyline, may also provide pain relief.

Whenever possible, medication use should be avoided or minimized to reduce the risk of side effects. If pain is severe, a pain specialist should be consulted in order to make sure all options for pain treatment are considered.

Physical therapy exercises to maintain muscle strength may be appropriate for some people. Orthopedic assistance with different aids (such as braces, splints, or other appliances) may maximize the ability to use the arm.

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

• Partial or complete arm paralysis
• Partial or complete loss of sensation in the arm, hand, or fingers
• Recurrent or unnoticed injury to the hand or arm due to diminished sensation
• Deformity of the hand or arm, mild to severe, which can lead to contractures