J Korean Neurol Assoc.  2022 May;40(2):181-184. 10.17340/jkna.2022.2.15.

A Diagnostic Dilemma: Normal Repetitive Nerve Stimulation in Lambert-Eaton Myasthenic Syndrome

• Jeong YH
• Seok HY

• KMID: 2529614
• DOI: http://doi.org/10.17340/jkna.2022.2.15

Abstract

It is important for the diagnosis of Lambert-Eaton myasthenic syndrome (LEMS) to confirm the incremental response at high-rate stimulation or after brief exercise in the repetitive nerve stimulation (RNS) test. Therefore, it may be difficult to diagnose LEMS if the RNS test is normal initially. We report a patient with LEMS whose diagnosis was delayed due to normal RNS findings. We believe that anti-P/Q-type voltage-gated calcium channel antibody testing is crucial in the diagnosis of LEMS.

Keyword

Lambert-Eaton myasthenic syndrome; Electrodiagnosis; Anti-voltage-gated calcium channel autoantibody