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Electrophysiologic findings in amyloid myopathy
Author(s) -
Rubin Devon I.,
Hermann Robert C.
Publication year - 1999
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199903)22:3<355::aid-mus8>3.0.co;2-8
Subject(s) - myopathy , electromyography , medicine , compound muscle action potential , muscle biopsy , motor unit , fibrillation , peripheral neuropathy , myalgia , population , pathology , cardiology , anatomy , electrophysiology , biopsy , endocrinology , atrial fibrillation , physical medicine and rehabilitation , environmental health , diabetes mellitus
Myopathy is an uncommon manifestation of systemic amyloidosis. A retrospective chart review of 17 patients seen between 1975 and 1997 with biopsy‐proven amyloid myopathy was performed to characterize the electrophysiologic features. Nerve conduction study abnormalities occurred in 14 of 17 patients (82%). The most common abnormality was a low peroneal and/or tibial compound muscle action potential amplitude ( n = 9). Mild abnormalities also occurred in seven other nerves. Repetitive stimulation at 2 Hz in 10 nerves was normal. Electromyography demonstrated fibrillation potentials in 69% of muscles, most frequently in the gluteus medius (90%) and paraspinals (87%). The fibrillation potentials were sparse in 60%. Short‐duration, low‐amplitude motor unit potentials (MUPs) were found in 72% of the muscles examined, were mild in 81%, and were more common in proximal muscles. Long‐duration MUPs were found in 19% of muscles and a mixed population of MUPs in 4%. These findings are similar to those of common chronic, inflammatory myopathies. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 355–359, 1999