N/A Campbell University School of Osteopathic Medicine Raleigh, North Carolina, United States
Clinical Scenario or Case: A 41 year old woman presented with atrophy and loss of function in her hands. In the past, she had seen primary care providers who thought her symptoms were caused by compression and possible carpal tunnel syndrome. In 2021, the patient underwent carpal tunnel surgery for treatment of the left wrist. However, following the procedure not only did her symptoms not resolve, but they progressively started getting worse. She was then referred to neurology for further workup. The neurologist conducted a thorough physical exam as well as ordered an US, EMG, blood work, lumbar puncture, and an autoimmune panel. Her EMG and US showed she had multiple sites of irritation at noncompressible sites, supporting the conclusion that her symptoms were not due to a compressive etiology such as carpal tunnel. Further, her MAG IGM autoantibody panel came back positive with a high value of 5725 btu. When combining her physical exam, labs, and imaging findings, the neurologist was able to conclude that the patient likely had MAG associated polyneuropathy. With this diagnosis, the patient was able to be started on rituximab and has since seen improvement.
Evidence/Literature Review: MAG Associated Demyelinating Polyneuropathy is an autoimmune condition where IgM in the host mistakenly attacks its own myelin associated glycoprotein (MAG), resulting in the loss of function in peripheral nerves. The condition is very rare, with only .8 to 8.9 new cases found per 100,000 per year.
Unique Aspects of Case: MAG Polyneuropathy is rare. In this case, the patient underwent carpal tunnel surgery of the left wrist due to a misdiagnosis. Only through EMG and US was the diagnosis able to be found.
Recommendations/Conclusions: With severe symptoms such as weakness or sensory deficit, patients should undergo confirmatory nerve conduction studies. Current recommended treatment for MAG polyneuropathy is rituximab but development of improved treatments are underway.
