2021 Workshop Handout Bundle-Myopathies: EDX Approach

Myopathies: EDX Approach - Naddaf

Pdf Summary

Electrodiagnostic testing (EDX) is an important tool in evaluating patients with suspected myopathy. It can help confirm a myopathy, differentiate it from neuropathy, identify specific myopathy patterns, assess disease activity, guide muscle biopsy selection, and monitor treatment response. Myopathies can be acquired or hereditary, with various classifications based on underlying mechanisms, clinical phenotype, or genetic findings. The clinical phenotype of a myopathy is crucial in guiding the EDX evaluation. Different patterns of weakness can occur, such as diffuse weakness or involvement of specific muscle groups. Proximal myopathies are the most common, but other patterns, such as distal or axial myopathies, are often misdiagnosed or underdiagnosed. Overlap presentations, where myopathy coexists with neuropathy or neuromuscular transmission defects, can complicate the EDX approach. A standardized approach to EDX testing is recommended to maximize yield and provide meaningful information. Routine nerve conduction studies and needle electromyography (EMG) are key components of EDX testing in myopathies. Needle EMG findings can reveal important information about myopathy activity and type, but interpretations should be cautious as there can be overlap in findings between different myopathies. Selecting the appropriate muscle for biopsy is important, and muscles with moderate weakness and abnormal EMG findings are preferred targets. Strategies to simplify the complexity of myopathies include adopting a systematic approach, sampling affected muscles, being descriptive in reporting findings, and avoiding forcing findings into pre-defined categories. Overall, a standardized approach and careful evaluation of clinical phenotype and EDX findings can help in the accurate diagnosis and management of myopathies.

Keywords

Electrodiagnostic testing

myopathy evaluation

neuropathy differentiation

myopathy patterns

disease activity assessment

muscle biopsy selection

proximal myopathy

distal myopathy

axial myopathy

standardized approach