This issue of Continuum is devoted to the diagnosis and management of our patients with disorders that localize to the muscles (and their subcellular structures and function) or to the neuromuscular junction. To accomplish this goal, I am so pleased that Dr Nicholas E. Johnson accepted my request to be the guest editor of this issue, and I extend my gratitude to him for inviting such an outstanding team of experts to contribute to this issue.
I am so pleased that Dr Nicholas E. Johnson accepted my request to be the guest editor of this issue, and I extend my gratitude to him for inviting such an outstanding team of experts to contribute to this issue.
The issue begins with the article by Drs Mamatha Pasnoor and Mazen M. Dimachkie, who discuss their approach to muscle and neuromuscular junction disorders. This article serves as a primer and underpinning to all the articles that follow in this issue. Dr Namita A. Goyal then reviews the current diagnostic and management considerations of the immune-mediated myopathies. In the next article, Dr Conrad C. Weihl discusses sporadic inclusion body myositis and the other rimmed vacuolar myopathies.
Moving on to the muscular dystrophies, Dr Matthew P. Wicklund reviews the historical categorization, diagnosis, and management of the muscular dystrophies that have a limb-girdle phenotype. Dr Mathula Thangarajh next discusses the diagnosis and management of the dystrophinopathies, conditions in which current management has altered the progression of disease. Dr Russell J. Butterfield then reviews the congenital muscular dystrophies and congenital myopathies; modern genetic diagnosis has shown that these disorders have significant phenotypic overlap and that clinical characterization into one category or the other is less straightforward than previously recognized. Dr Kathryn R. Wagner next discusses the facioscapulohumeral muscular dystrophies (types 1 and 2), conditions in which the molecular mechanisms of disease have been increasingly elucidated, hopefully paving the way for future therapeutic options. Dr Nicholas E. Johnson then reviews the diagnosis and management considerations for the myotonic muscular dystrophies type 1 and type 2.
Dr Valeria A. Sansone reviews the diagnosis and management of the episodic muscle disorders, particularly the periodic paralyses and the nondystrophic myotonias. Next, Drs Christopher T. Doughty and Anthony A. Amato review the pathogenesis, clinical features, and management of the toxic myopathies that may occur as adverse effects of a number of common medications and substances, as well as weakness that occurs in the setting of critical illness. Dr Bruce H. Cohen next provides an encyclopedic review of the many presentations of the mitochondrial disorders and the metabolic (lipid and glycogen) myopathies.
The final two review articles of the issue cover disorders of the neuromuscular junction. First, Dr Emma Ciafaloni reviews the diagnosis and management of myasthenia gravis and congenital myasthenic syndromes. Next, Dr Amanda C. Guidon discusses the postsynaptic neuromuscular junction disorders (specifically Lambert-Eaton myasthenic syndrome and botulism), as well as the evolving spectrum of neuromuscular disorders, including immune-related myasthenia gravis related to immune checkpoint inhibitor therapies for cancer.
After reading the issue and taking the Postreading Self-Assessment and CME Test written by Drs Adam G. Kelly and Douglas J. Gelb, you may earn up to 20 AMA PRA Category 1 CreditsTM toward self-assessment and CME or, for Canadian participants, a maximum of 20 hours toward the Self-Assessment Program (Section 3) of the Maintenance of Certification Program of the Royal College of Physicians and Surgeons of Canada. Additional credit can be obtained by listening to Continuum Audio interviews associated with this and other Continuum issues, available to all subscribers, and completing tests on the Continuum Audio web platform or mobile app. Continuum Audio is also accredited by the Royal College of Physicians and Surgeons of Canada.
I would like to offer my sincere appreciation to Dr Johnson for his expert guest editorship of this multifaceted issue and for enlisting such expert authors in the fields of muscle and neuromuscular junction disease to assist us in the diagnosis and management of the patients who present to us with any of these disorders.
—STEVEN L. LEWIS, MD, FAAN