Although this pattern recognition approach to myopathy may have limitations, it can be extremely helpful in narrowing the differential diagnosis and therefore minimizing the number of laboratory studies that must be ordered to confirm the diagnosis. There will always be patients with muscle disease who will not fit neatly into any of these six categories. In addition, patients with involvement of other areas of the neuroaxis such as the motor neuron, peripheral nerve, or neuromuscular junction may also frequently present with one of these patterns. For example, although proximal greater than distal weakness is most often seen in a myopathy, patients with acquired demyelinating neuropathies (Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy) often have proximal as well as distal muscle involvement. Careful consideration of the distribution of muscle weakness and attention to these common patterns of involvement in the context of other aspects of the neurological examination and laboratory evaluation will usually, however, lead the clinician to a timely and accurate diagnosis.
Carlayne E. Jackson, M.D., Professor of Neurology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78284-7883. E-mail: email@example.com .
Semin Neurol. 2008;28(2):228-240. © 2008 Thieme Medical Publishers
Cite this: Clinical Approach to Muscle Diseases - Medscape - Apr 01, 2008.