A 33-year-old woman presents with pain and weakness of the left upper extremity. Her symptoms started 5 days ago with severe pain around the left shoulder and then gradual weakness in the arm. She also gives a history of an upper respiratory viral illness a couple weeks prior to the onset of symptoms. Her examination is remarkable for weakness of the left deltoid, biceps, and triceps muscles with loss of biceps and triceps reflexes. Motor strength and deep tendon reflexes are normal in the right upper extremity and both lower extremities. Her symptoms are most consistent with which of the following disorders?
A. amyotrophic lateral sclerosis
B. carpal tunnel syndrome
C. Guillain-Barré syndrome (acute inflammatory demyelinating polyradiculopathy)
D. Parsonage-Turner syndrome (idiopathic brachial plexopathy )
E. subclavian steal syndrome
