S46. A case of inflammatory neuropathy associated with anti-myelin-associated glycoprotein antibody and serial neurosonographic findings

Abstract

Introduction We describe a case of inflammatory neuropathy associated with anti-myelin-associated glycoprotein antibody and serial neurosonographic findings. Methods We used electrodiagnostic test and neurosonography serially. Results A 63-year-old man presented with weakness of both hands 3 days ago. Neurological examination showed mild motor weakness of both arms, and left leg (impossible heel gait and hopping). He complained no sensory loss but deep tendon reflexes are hypoactive in the upper limbs. NCS revealed sensorimotor demyelinating polyneuropathy with conduction block (CB) over left median, ulnar and peroneal nerves. CSF study showed slightly increased protein. In diagnosis of GBS, we started IVIG. Serum test of anti-ganglioside antibodies and anti-MAG antibody displayed only positive for anti-MAG antibody. Serum and urine protein electrophoresis with immunofixation showed no monoclonal gammopathy. Neurosonography for 3 months exhibited relative swelling of bilateral proximal median nerves, right whole ulnar nerve, right sciatic nerve, right peroneal and tibial nerves at popliteal fossa, left tibial nerve at calf, left peroneal nerve at fibular head. After IVIG, his motor power was restored progressively but not completely. In F/U NCS, CMAPs are increased and CBs are disappeared. Serial nerve US showed mild decrements of cross section areas of formerly enlarged nerves. The decrease of nerve cross-sectional area is more prominent in proximal part of tested nerves. Conclusion Neuropathy with anti-MAG antibodies is an acquired demyelinating polyneuropathy with slowly progressive primary sensory impairment associated with gait ataxia and postural tremor at the upper limbs. The neurophysiological findings usually indicate a symmetric demyelinating damage with uniform slowing of NCV and prolonged DML, without CB. But in this case, the patient had no ataxia and NCS showed multifocal CB. US in patient with anti-MAG neuropathy often revealed nerve regional enlargement in and out of entrapment sites. Further prospective studies may clarify the evolution of US changes according to history, neurophysiology and therapeutic response.