Approach to Myopathies-Dr. Naddaf - Approach to Myopathies

Dr. Naddaf - Approach to Myopathies

Pdf Summary

In this presentation at the AANEM spring meeting in 2022, Dr. Elie Naddaf discusses the approach to myopathies, focusing on muscle biopsy, electromyography (EMG), and clinical correlation. The learning objectives include describing various muscle fiber abnormalities, differentiating endomysial from perimysial pathology, and correlating muscle biopsy findings with EMG and clinical findings.<br /><br />Dr. Naddaf begins by discussing normal muscle anatomy and muscle pathology overview. He explains that muscle fiber abnormalities can occur in the endomysium or perimysium compartments of the muscle, or there may be no abnormalities present. He also provides an overview of normal neuromuscular junction anatomy.<br /><br />The presentation then delves into the causes of spontaneous activity on EMG, including necrosis, vacuoles, splitting, and inclusions. Non-specific esterase staining is discussed as a method for identifying muscle fiber pathology.<br /><br />The significance and interpretation of various muscle fiber abnormalities are explored, with a focus on necrosis and regeneration as indicators of active/acute myopathic components.<br /><br />Differentiating between various etiologies of muscle fiber abnormalities is discussed, with an emphasis on history and physical examination as important tools. Specific staining techniques, such as acid phosphatase, MxA immunostain, and modified trichrome, can help differentiate between different types of inflammatory processes.<br /><br />Polymyositis is clarified as a specific type of myositis characterized by endomysial inflammation with autoaggressive features, lacking rimmed vacuoles or protein aggregates. It is categorized separately from other idiopathic inflammatory myopathies.<br /><br />Miscellaneous abnormalities, such as ragged blue fibers and staining patterns of enzymes like succinate dehydrogenase, cytochrome C oxidase, and NADH dehydrogenase, are mentioned briefly.<br /><br />The presentation concludes with a discussion on the correlation between muscle biopsy and EMG, and references a paper by Dr. Naddaf and colleagues in Frontiers in Neurology in 2018.<br /><br />Contact information for Dr. Naddaf is provided for further inquiries.

Keywords

myopathies

muscle biopsy

electromyography

clinical correlation

muscle fiber abnormalities

endomysial pathology

perimysial pathology

neuromuscular junction anatomy

spontaneous activity on EMG

necrosis

EMG