Inclusion Body Myositis : Clinical Features and Electrophysiological Findings |
Kwang-Kuk Kim |
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Copyright © 2006 The Korean Society of Clinical Neurophysiology |
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium,
provided the original work is properly cited. |
ABSTRACT |
Sporadic inclusion body myositis (s-IBM) is an aquired slowly progressive inflammatory myopathy with unknown etiology. Although light microscopic abnormalities and characteristic histopathology on muscle biopsy distinguishes from other inflammatory myopathies, vacuolated muscle fibers, intracellular amyloid deposits or tubulofilaments in electromicroscopic findings are not definite in some patients. This review shows the prominently involved muscles in s-IBM and specific or nonspecific electrophysiologic manifestations from reported data for helping the diagnosis of definite-or probable-IBM patients. In lower limbs, the quadriceps is predominantly involved, as is iliopsoas, and tibialis anterior is common. In the upper limbs, the greatest weakness is in forearm finger flexors. Finger extensors, biceps and triceps also are moderately to prominently involved. The majority of patients demonstrate polyphasic MUAPs that are short in duration. An additional striking feature is the concomitant documentation of long-duration, large-amplitude, polyphasic MUAPs. In spite of the frequent mixed myopathic-neurogenic electromyographic findings of IBM, just like that of chronic myositis, asymmetric, slowly progressive weakness of flexor digitorum profundus or quadriceps femoris muscles after age of 50 is very necessary condition for the diagnosis of IBM. |
Key words:
Electromyography, Inclusion body myositis, Flexor digitorum profundus, Quadriceps femoris. |
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