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Seronegative myasthenia gravis: comparison of neurophysiological picture in MuSK+ and MuSK− patients
Author(s) -
Padua L.,
Tonali P.,
Aprile I.,
Caliandro P.,
Bartoccioni E.,
Evoli A.
Publication year - 2006
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/j.1468-1331.2006.01214.x
Subject(s) - repetitive nerve stimulation , myasthenia gravis , medicine , edrophonium , electromyography , neurophysiology , neuromuscular transmission , physical medicine and rehabilitation , psychiatry
The aim of this study was to compare the neurophysiological and clinical pictures of a large sample of seronegative myasthenia gravis (SNMG) patients with and without anti‐MuSK antibodies. Fifty‐two consecutive SNMG patients were retrospectively evaluated. They had undergone an extended neurophysiological evaluation: repetitive nerve stimulation (RNS), single fiber EMG (SFEMG), and electromyography (EMG) with nerve conduction study. A muscle biopsy was performed in 11 of 52 patients, the edrophonium test in 44 of 52 patients and anti‐AChR antibodies and anti‐MuSK antibodies were tested in all patients. Anti‐MuSK antibodies were detected in 25 SNMG patients (48.1%). The number of women in the MuSK+ group was significantly higher ( P = 0.01) than in the MuSK− group. Seronegative MuSK+ patients are more severely affected and the deficit often involves the bulbar and the respiratory muscles. No statistically significant differences were observed in the edrophonium test between MuSK+ and MuSK− groups. The RNS test was abnormal in a significantly higher number of MUSK− patients than MUSK+ patients ( P < 0.00001). With regard to SFEMG data, MuSK− patients were characterized to have more severe neurophysiological pattern. Our observations showed several differences between the clinical and neurophysiological pictures of MUSK+ and MUSK− patients.