Pseudomyotonic Discharge
An EMG pattern that resembles myotonic discharge but lacks the characteristic frequency and amplitude variation, often seen in inflammatory myopathies.
Full Definition
Pseudomyotonic discharge is an electromyographic finding that superficially resembles true myotonic discharge but lacks the pathognomonic waxing and waning of amplitude and frequency. Instead of the smooth modulation seen in true myotonia, pseudomyotonic discharges show abrupt changes in firing pattern or may maintain relatively constant amplitude and frequency. This pattern is commonly observed in inflammatory myopathies, particularly polymyositis and dermatomyositis, and represents a different underlying pathophysiology from true myotonic disorders. Accurate identification is crucial for differential diagnosis.
Usage
Usage note: Always hyphenate as a compound term.
In Context
- "Pseudomyotonic discharges were observed in the deltoid muscle." — EMG report in inflammatory myopathy
- "The discharge pattern was pseudomyotonic rather than truly myotonic." — Electrodiagnostic interpretation