Clinical and electrophysiological characteristics of Lambert-Eaton myasthenic syndrome: a retrospective study in forty-five patients / 中华神经科杂志

ABSTRACT

Objective To analyze the symptoms and signs in forty-five Lambert-Eaton myasthenia syndrome (LEMS) patients retrospectively. Characteristics of electrophysiological examinations were investgated. Methods Forty-five LEMS patients were reviewed and information gathered regarding clinical complains neurological symptoms, and other concomitant diseases. The records showed that repetitive nerve stimulation (RNS) and nerve conduction velocity (NCV) were performed in all patients. Needle electromyography (EMG) and skin sympathetic response (SSR) were performed in some patients. Results (1) The mean age of neurological clinical onset age was (51.2 ±6. 8) years old. The two most common symptoms were slight weakness of lower extremities ( n = 35 ) and upper extremities (n= 5). Dysarthria was found in 3 patients and neck weakness in 2 patients. Tendon reflex decreased and disappeared in 38 patients. Autonomic nervous system manifestations were presented in 30 patients. (2) RNS increasing was observed in all patients from 156% to 636%. Low frequency RNS abnormalities were found in 29 patients.Sensory nerve conduction velocity abnormalities or sensory nerve conduction velocity combined motor nerve conduction velocity abnormalities were found in 19 patients ( 42% ). Of the 30 patients who underwent a needle EMG examination, 20 had myogenic or neurological damage. Thirteen abnormal findings were observed in 25 patients who underwent SSR examination. Conclusion The most common manifestations were weakness in lower extremities and autonomic nervous system dysfunction. Many abnormal electrophysiological results were found in LEMS patients, including NCV and EMG abnormalities. These findings indicated that clinical manifestations exceed the neuromuscular junction and perhaps included the peripheral nerve and muscle.