Myopathies are a heterogeneous group of disorders that can be challenging to diagnose. The purpose of this review is to provide a diagnostic approach based predominantly on the clinical history and neurologic examination. Laboratory testing that can subsequently be used to confirm the suspected diagnosis based on this pattern recognition approach will also be discussed.
Over the past decade, numerous discoveries have allowed clinicians to diagnose myopathies with genetic testing. Unfortunately, the testing is extremely expensive and frequently not covered by insurance.
Careful consideration of the pattern of muscle weakness in addition to other aspects of the physical examination and diagnostic testing should assist the clinician in making a timely and accurate diagnosis and minimize the expense of confirmatory genetic testing.
The article “A Pattern Recognition Approach to Myopathy” by Drs Carlayne Jackson and Richard Barohn reflects the thoughtful approach that these experts have used, taught, and published for a number of years. The original version of this material was written by Dr Barohn and published in the 2000 edition of Cecil Textbook of Medicine (published in 1999), and subsequent updated and evolved versions of this information (by Dr Barohn or Dr Jackson) appeared in editions of Cecil Textbook of Medicine in 2004 and 2008 (now published by Elsevier), issues of Continuum: Lifelong Learning in Neurology in 2000 and 2006, an issue of Seminars of Neurology in 2008, and course syllabi from the American Academy of Neurology (AAN) as well as the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM). Because we feel that the material presented in this article continues to be important for our readers so that they can use this approach in the assessment and care of their patients withmuscle disease, we include an updated version in this issue.
Address correspondence to Dr Carlayne Jackson, 8300 Floyd Curl Drive, Mail Code 7883, San Antonio, Texas, 78229-3900, firstname.lastname@example.org.
Relationship Disclosure: Dr Jackson has received research support from Biogen Idec; Cytokinetics, Inc; Knopp Neurosciences, Inc; the National ALS Association; Phillips Respironics; and the US Food and Drug Administration Office of Orphan Products Development. Dr Barohn has served on the speaker’s bureaus of Genzyme Corporation and Grifols; on the advisory boards of MedImmune, LLC, and Novartis Corporation; and as a consultant for NuFACTOR. Dr Barohn has received research support from Biogen Idec; BioMarin Pharmaceutical Inc; Cytokinetics, Inc; Genzyme Corporation; Knopp Neurosciences, Inc; Neuraltus Pharmaceuticals, Inc; the National Institute of Neurological Disorders and Stroke; the NIH; PTC Therapeutics; Sangamo BioSciences, Inc; Teva Pharmaceutical Industries Ltd; and the US Food and Drug Administration Office of Orphan Products Development.
Unlabeled Use of Products/Investigational Use Disclosure: Drs Jackson and Barohn report no disclosures.