Sener U, Martinez-Thompson J, Laughlin RS, Dimberg EL, Rubin DI. Needle electromyography and histopathologic correlation in myopathies.
Muscle Nerve 2018;
59:315-320. [PMID:
30414326 DOI:
10.1002/mus.26381]
[Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 11/02/2018] [Accepted: 11/06/2018] [Indexed: 11/10/2022]
Abstract
INTRODUCTION
Needle electromyography (EMG) findings help confirm myopathy and may indicate specific pathologic changes on muscle biopsy.
METHODS
We conducted a retrospective chart review of 218 consecutive patients referred for muscle biopsy. Presence of specific needle EMG findings was correlated with pathologic findings of inflammation, necrosis, splitting, and vacuolar changes. Sensitivity, specificity, and positive and negative predictive values of specific EMG findings for pathologic changes were calculated.
RESULTS
Short-duration motor unit potentials (MUP) were sensitive (83%-94%) but not specific (34%-49%) for pathologic changes. Fibrillation potentials were 65%-74% sensitive and 58%-81% specific for inflammation, necrosis, splitting, or vacuolar changes. The absence of fibrillation potentials had high negative predictive value (82%-93%) for inflammation, splitting, or vacuolar changes.
DISCUSSION
Fibrillation potentials and short-duration MUPs predict pathologic changes of muscle fiber necrosis, splitting, and/or vacuolar changes (as seen with inflammatory myopathies and muscular dystrophies). Absence of fibrillation potentials suggests other myopathologic changes (e.g., congenital myopathy). Muscle Nerve 59:315-320, 2019.
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