An Experience of Electrophysiological Studies on a Patient With Anti-MuSK and Anti-acetylcholine Receptor Antibody Negative Myasthenia Gravis(Special Issue in Hornor of the Retirement of Professor Makoto Iwata at the Department of Neurology, Tokyo Womenu27s Medical University)

摘要

We encountered an acetylcholine receptor (AChR) and muscle-specific tyrosine kinase (MuSK) antibody-negative myasthenia gravis (MG) patient with unique semiological and electrophysiological features. MG patients are divided into those with positive and negative anti-AChR antibody. It is occasionally difficult to diagnose as MG in patients with negative anti-AChR antibody. Because in our patient both anti-AChR and MuSK antibodies were negative, we had great difficulty in making definite diagnosis of MG. However, we were able to diagnose our patient as MG using combined edrophonium test and electrophysiological study. This combination may have a possibility to be applied in similar cases like ours. In addition, it was suggested from unique semiological and electrophysiological features that our patient had different pathogenesis from usual MG patients.