[Neurogenic electromyographic activity in a patient with non-paraneoplasic Lambert-Eaton syndrome].
BACKGROUND
Lambert-Eaton myasthenic syndrome (LEMS) is a rare presynaptic disorder of the neuromuscular junction. Electrodiagnosis is characterized by compound muscle action potentials of small amplitude at rest, normalizing immediately after brief exercise or high-rate nerve stimulation. Needle electromyographic (EMG) activity is classically described as normal or myogenic.


METHODS
We report the case of a young patient with a non-paraneoplastic LEMS in whom the initial electroneuromyographic examination showed neurogenic changes in needle EMG concomitant with typical features of presynaptic neuromuscular junction disorder at single and repetitive nerve stimulation.


CONCLUSIONS
Neurogenic EMG abnormalities were not previously described in patients with LEMS and could result from "functional" reversible denervation, depending on the presence of anti-calcium channel antibodies at axon terminals.


CONCLUSIONS
Neurogenic features in needle EMG examination in case of subacute motor deficiency should not eliminate the possibility of a presynaptic neuromuscular junction disorder, such as LEMS.
Lapergue
B
B
Service de neurologie, hôpital Henri-Mondor, AP-HP, Université Paris XII, Créteil.
Lefaucheur
J-P
JP
Bourahoui
A
A
Nordine
T
T
Hosseini
H
H
Créange
A
A
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004568:Electrodiagnosis; D004576:Electromyography; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D015624:Lambert-Eaton Myasthenic Syndrome / Q000175:diagnosis / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology; D009420:Nervous System / Q000503:physiopathology; D009460:Neurologic Examination
D007074:Immunoglobulin G