RNS Simplified for the EDX Lab Technologists, Residents, Fellows, and APPs-Dr. Bandyopadhyay Presentation

Dr. Bandyopadhyay Presentation

Pdf Summary

The document is an educational guide on Repetitive Nerve Stimulation (RNS) for lab technicians, residents, fellows, and Advanced Practice Providers (APPs), authored by Dr. Sankar Bandyopadhyay from Penn State, with no financial disclosures. It aims to educate on neuromuscular junction anatomy, the basics and methodology of RNS, how to identify decrement and increment/facilitation, and common mistakes in testing.<br /><br />Key terms like decrement, increment, isometric contraction, and facilitation/pseudofacilitation are defined, particularly focusing on changes in the amplitude of compound muscle action potentials (CMAP) during testing. A decrement is the percentage decrease in CMAP from baseline, while an increment is a percentage increase.<br /><br />The methodology section advises on patient selection for conditions such as Myasthenia Gravis (MG), Lambert-Eaton Myasthenic Syndrome (LEMS), botulism, and congenital myasthenic syndrome. It recommends holding pyridostigmine (a medication affecting neuromuscular transmission) before testing and selecting appropriate nerves/muscles like the ulnar, spinal accessory, or facial. Techniques for immobilization, supramaximal stimulation, and testing protocols for post-tetanic exhaustion and facilitation are outlined.<br /><br />Conditions like MG, LEMS, and botulism are discussed, showing expected RNS patterns. MG typically presents a decrement in advanced cases, while LEMS shows a significant facilitation after brief exercise. Botulism may present variable results, especially notable in infants.<br /><br />The guide emphasizes avoiding common pitfalls such as improper warm-up, incorrect muscle choice, inadequate stimulus, and sensitivity adjustments. The methodology highlights the importance of patient selection, proper timing relative to medication, and testing protocols.<br /><br />This comprehensive guide helps practitioners accurately conduct and interpret RNS tests, ultimately aiding the diagnosis of neuromuscular disorders.

Keywords

Repetitive Nerve Stimulation

neuromuscular junction

nmj

decrement

increment

Myasthenia Gravis

Lambert-Eaton Myasthenic Syndrome

botulism

compound muscle action potentials

facilitation

pyridostigmine

nmj

neuromuscular junction