INTRODUCTION/BACKGROUND: The diagnosis of brachial plexitis is based on history and clinical findings, supported by needle EMG and MRI. MR neurography can detect focal and multifocal inflammation within nerve.
OBJECTIVE: To determine if MR neurography allows objective data mirroring clinical improvement in brachial plexitis.
CASE REPORT: A 39-year-old man developed sudden onset pain in his left shoulder after a mild infection, which intensified over 3-4 days. Weakness followed, being unable to lift his left arm above the level of his shoulder. There were no sensory symptoms. There was a remote history of Bell’s palsy, but no relevant family history. Initial examination showed weakness of the left deltoid and infraspinatus (2/4). Reflexes were present. Needle EMG/NCSs showed left C5 radiculopathy, primarily involving the anterior ramus division with severe denervation of C5-innervated muscles, then progressive reinnervation of the C5 muscles through axonal regeneration. A left brachial plexus MR neurography with gadolinium showed an enlarged hyperintensity in the C5 nerve root at the level of the interscalene triangle with a denervation pattern edema of regional muscles. The patient was treated with IVIg. Ten months after onset, strength of all muscles is normal, although there is decreased muscle bulk in his deltoid and pectoral muscles. Serial MRIs show progressively decreasing nerve root hyperintensity and size in the post foraminal nerve root. The last MRI and needle EMG/NCSs were normal, correlating with the clinical syndrome.
SUMMARY/CONCLUSION: MR neurography of the brachial plexus may be important in diagnosis and prognosis in patients with brachial plexitis.