Approach to Myopathies-Dr. Hayat - Approach to Myopathies

Dr. Hayat - Approach to Myopathies

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The document discusses the electrodiagnostic approach to myopathies in 2022. It starts by listing the author's financial disclosures and objectives of the presentation. The etiologies of myopathies are categorized into genetically inherited, myopathies with metabolic abnormalities, muscular dystrophies, channelopathies, acquired myopathies, and toxic myopathies. The evaluation of myopathies includes NCV, EMG, ultrasound, MRI scan, and muscle biopsy. Decreased insertional activity can indicate fibrous or fatty tissue replacement, edema, or impaired muscle fiber depolarization, while increased insertional activity can indicate positive sharp waves. Spontaneous activity includes positive sharp waves, fibrillations, myotonic discharges, and complex repetitive discharges. Motor Unit Action Potentials (MUAP) in myopathy are polyphasic, short duration, lower amplitudes, and show early recruitment. The document also lists commonly examined muscles in the upper and lower extremities. Paraspinal muscles can be a unique abnormality in inflammatory myopathies. Irritative myopathies such as inflammatory myopathies, Duchenne's muscular dystrophy, and myotonic dystrophy exhibit specific MUAP and spontaneous activity patterns. Inflammatory myopathies show fibrillation potentials in recent-onset cases and both fibrillation potentials and MUAP changes in established cases. Congenital/endocrine myopathies typically show normal insertional and spontaneous activity but may have myopathic units and electric myotonia. Critical illness weakness presents with severe disintegration of motor units, while mitochondrial disorders/myopathies may show concurrent neuropathy and myopathic units. The document concludes with requests for questions and comments.

Keywords

electrodiagnostic approach

myopathies

2022

evaluation

insertional activity

spontaneous activity

Motor Unit Action Potentials

commonly examined muscles

inflammatory myopathies

congenital/endocrine myopathies