Repetitive nerve stimulation test in myasthenic crisis

Muscle Nerve. 2019 May;59(5):544-548. doi: 10.1002/mus.26390. Epub 2019 Jan 9.

Abstract

Introduction: Herein we report our experience with the repetitive nerve stimulation (RNS) test in myasthenia gravis (MG) crisis.

Methods: The various parameters of the RNS tests in 26 patients with MG crisis were analyzed.

Results: In 18 (69%) patients, MG crisis is the first manifestation of MG. RNS tests were abnormal in 24 (92%) patients by decrement at low-rate stimulation in any of 4 tested muscles. Three patterns of abnormality were found: MG pattern (decrement at low-rate stimulation) in 23 patients; Lambert-Eaton myasthenic syndrome pattern in 1 patient; and cholinergic crisis pattern in 1 patient.

Discussion: During MG crisis, the RNS test can serve as a rapid and sensitive diagnostic tool for MG in a majority of patients. Muscle Nerve 59:544-544, 2019.

Keywords: MG; RNS test; electrodiagnostic test; myasthenia gravis; myasthenic crisis; repetitive nerve stimulation test.

MeSH terms

  • Action Potentials*
  • Adult
  • Aged
  • Diagnostic Techniques, Neurological
  • Disease Progression
  • Electric Stimulation / methods
  • Electromyography / methods
  • Female
  • Humans
  • Lambert-Eaton Myasthenic Syndrome / diagnosis*
  • Lambert-Eaton Myasthenic Syndrome / physiopathology
  • Male
  • Middle Aged
  • Myasthenia Gravis / diagnosis*
  • Myasthenia Gravis / physiopathology
  • Peripheral Nerves