Abstract
Brachial plexopathy is a constellation of symptoms consisting of neurogenic pain and associated weakness that radiates from the shoulder into the supraclavicular region and upper extremity. There are many causes of brachial plexopathy, but some of the more common ones include compression of the plexus by cervical ribs or abnormal muscles (e.g., thoracic outlet syndrome), invasion of the plexus by tumor (e.g., Pancoast’s tumor syndrome), direct trauma to the plexus (e.g., stretch injuries and avulsions), inflammatory causes (e.g., Parsonage-Turner syndrome and herpes zoster), and postradiation plexopathy. Patients suffering from brachial plexopathy complain of pain radiating to the supraclavicular region and upper extremity. The pain is neuritic in character and may take on a deep, boring quality as the plexus is invaded by tumor. Movement of the neck and shoulder exacerbates the pain, so patients often try to avoid such movement. Frozen shoulder often results and may confuse the diagnosis. If thoracic outlet syndrome is suspected, the Adson test may be performed.
Keywords
brachial plexopathy, Pancoast tumor, Parsonage-Turner syndrome, herpes zoster, shoulder pain, cervical radiculopathy, carcinoma, brachial plexus block
ICD-10 CODE G54.0
The Clinical Syndrome
Brachial plexopathy is a constellation of symptoms consisting of neurogenic pain and associated weakness that radiates from the shoulder into the supraclavicular region and upper extremity ( Fig. 22.1 ). There are many causes of brachial plexopathy, but some of the more common ones include compression of the plexus by cervical ribs or abnormal muscles (e.g., thoracic outlet syndrome), invasion of the plexus by tumor (e.g., Pancoast’s tumor syndrome), direct trauma to the plexus (e.g., stretch injuries and avulsions), inflammatory causes (e.g., Parsonage-Turner syndrome, herpes zoster), and postradiation plexopathy ( Fig. 22.2 ).
Signs and Symptoms
Patients suffering from brachial plexopathy complain of pain radiating to the supraclavicular region and upper extremity. The pain is neuritic in character and may take on a deep, boring quality as the plexus is invaded by tumor. Movement of the neck and shoulder exacerbates the pain, so patients often try to avoid such movement. Frozen shoulder often results and may confuse the diagnosis. If thoracic outlet syndrome is suspected, the Adson test may be performed ( Fig. 22.3 ). The test is positive if the radial pulse disappears with the neck extended and the head turned toward the affected side. Because the Adson test is nonspecific, treatment decisions should not be based on this finding alone (see Testing ). If the patient presents with severe pain that is followed shortly by profound weakness, brachial plexitis should be considered; this can be confirmed with electromyography.
Testing
All patients presenting with brachial plexopathy, especially those without a clear history of antecedent trauma, must undergo magnetic resonance imaging (MRI) of the cervical spine and the brachial plexus. Computed tomography (CT) scanning and ultrasound imaging is a reasonable alternative if MRI is contraindicated. Electromyography and nerve conduction velocity testing are extremely sensitive, and a skilled electromyographer can delineate which portion of the plexus is abnormal. If an inflammatory basis for the plexopathy is suspected, serial electromyography is indicated, and MRI of the shoulder muscles often reveals muscle edema and denervation-induced atrophy ( Fig. 22.4 ). If Pancoast’s tumor or some other tumor of the brachial plexus is suspected, chest radiographs with apical lordotic views may be helpful. If the diagnosis is in question, screening laboratory tests consisting of a complete blood count, erythrocyte sedimentation rate, antinuclear antibody testing, and automated blood chemistry should be performed to rule out other causes of the patient’s pain.
