The differential diagnosis of upper extremity mononeuritis multiplex includes neuralgic amyotrophy, vasculitic neuropathy, and Lewis-Sumner syndrome. We describe 3 patients initially suspected of neuralgic amyotrophy, who had an extremely painful, protracted, progressive disease course, not fitting one of these established diagnoses. Nerve ultrasonography showed focal caliber changes of the roots, plexus, and limb nerves. Electromyography showed predominant multifocal axonopathy. Ongoing autoimmune neuropathy was suspected. Steroid treatment provided temporary relief, and intravenous immunoglobulin A sustained pain decrease and functional improvement. These patients appear to have extremely painful axonal inflammatory neuropathy, with a good response to immune-modulating treatment.
Keywords: Lewis-Sumner syndrome; brachial plexus; high-frequency imaging; inflammatory neuropathy; musculoskeletal; neuralgic amyotrophy; neuromuscular ultrasound; neurosonology (adult); peripheral nerve; treatment.
© 2017 by the American Institute of Ultrasound in Medicine.