Clinical Neurophysiology 126 (2015) 1638–1639
Contents lists available at ScienceDirect
Clinical Neurophysiology journal homepage: www.elsevier.com/locate/clinph
Letter to the Editor Ultrasonographic discharges
evaluation
of
myokymic
See Editorial, pages 1466–1467 Myokymic discharges are a group of motor unit action potentials that fire repetitively (Kimura, 2013). The etiologies for limb myokymic discharges include radiation-induced plexopathy, myelopathy, multiple sclerosis, inflammatory polyradiculopathy, ischemic neuropathy, inflammatory neuropathy, peripheral nerve hyperexcitability and other chronic disorders of the spinal cord and peripheral nerves (Albers et al., 1981). Myokymic discharges commonly accompany clinical myokymia (defined as a fine persistent quivering or rippling of muscles). Recent advent of neuromuscular sonography has shed light on pathological movements caused by neuromuscular diseases. Electro-sonographic correlation has been reported in fasciculation and possible fibrillations (Pillen et al., 2009; Reimers et al., 1996; Walker et al., 1990). Here, to characterize sonographic appearance of myokymic discharges, we present a simultaneous recording of myokymic discharges and sonographic images of muscle contraction. A 69-year-old man complained about gait disturbance since age 65. Clinical examination revealed features of length-dependent sensorimotor dysfunction (e.g., weakness, muscle atrophy, sensory loss), autonomic failure, and myokymia in his left arm. Nerve conduction studies revealed severe sensorimotor axonal polyneuropathy. Needle electromyography revealed evidence of diffuse active denervation, reinnervation, and myokymic discharges in the left biceps, which were further characterized by concurrent ultrasonography (Fig. 1 and Video 1). Ultrasonography showed repetitive, brief but sustained, tractive movements of the surface of the muscle occurring slightly after the onset of the myokymic discharges. Genetic testing revealed a heterozygous mutation (Val30Met) in the TTR gene, confirming the diagnosis of familial amyloid polyneuropathy. To the authors’ knowledge, simultaneous recording of myokymic discharges and myokymia has not been reported. Myokymia in the present patient differed from fasciculation because fasciculation appears as short jerky movements occurring irregularly and randomly in different areas of the muscles (Video 2). Of note, sonography might have greater sensitivity than visual inspection for detection of myokymia because of the ability to visualize deep muscle tissues by sonography, although future study should elucidate the point. In addition, due to the non-invasiveness of sonography, sonographic screen for suspicious muscle contractions would be confirmed by ‘‘echo-guided’’ needle EMG, which could result in a smaller number of needle insertion than unguided needle EMG proce-
dure to detect diagnostic electrical discharges. Thus, muscle sonography can play an indispensable role in the detection and characterization of abnormal, but potentially similar muscle movements such as rippling muscles. Interestingly, some of the myokymic discharges correlated with the patient’s inspiration, especially in the initial part of Video 1. It is possible that respiratory drive triggered firing of the myokymic discharges due to aberrant reinnervation, as reported in ‘‘breathing arm syndrome’’ (Lam and Engstrom, 2010; Swift et al., 1980). However, we regret that respiration was not monitored during the recording and the potential relationship between the myokymic discharges and respiration was unable to be further elucidated. Given the firing rate greater than 50 per minute shown in the EMG screen near the end of the Video 1 and the lack of clinical tachypnea, respiratory drive might have triggered myokymic discharges at least in the initial part of the video, when the firing and the respiratory rates were similar. Conflict of Interest None of the authors have potential conflicts of interest to be disclosed.
Fig. 1. Concurrent recording of the muscle contraction in the left biceps brachii by needle electromyography and ultrasonography.
http://dx.doi.org/10.1016/j.clinph.2014.10.154 1388-2457/Ó 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Letter to the Editor / Clinical Neurophysiology 126 (2015) 1638–1639
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.clinph.2014.10. 154. References Albers JW, Allen 2nd AA, Bastron JA, Daube JR. Limb myokymia. Muscle Nerve 1981;4:494–504. Kimura J. Electrodiagnosis in diseases of nerve and muscle: principles and practice. New York, USA: Oxford University Press; 2013. Lam L, Engstrom J. Teaching video NeuroImages: the breathing arm: respiratory brachial synkinesis. Neurology 2010;74:e69. Pillen S, Nienhuis M, van Dijk JP, Arts IM, van Alfen N, Zwarts MJ. Muscles alive: ultrasound detects fibrillations. Clin Neurophysiol 2009;120:932–6. Reimers CD, Ziemann U, Scheel A, Rieckmann P, Kunkel M, Kurth C. Fasciculations: clinical, electromyographic, and ultrasonographic assessment. J Neurol 1996;243:579–84. Swift TR, Leshner RT, Gross JA. Arm-diaphragm synkinesis: electrodiagnostic studies of aberrant regeneration of phrenic motor neurons. Neurology 1980;30:339–44. Walker FO, Donofrio PD, Harpold GJ, Ferrell WG. Sonographic imaging of muscle contraction and fasciculations: a correlation with electromyography. Muscle Nerve 1990;13:33–9.
Yusuke Osaki Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Naoko Takamatsu Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan
1639
Yoshimitsu Shimatani Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Atsuko Mori Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Keiko Maruyama Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Yoshimichi Miyazaki Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan
⇑
Hiroyuki Nodera Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan ⇑ Corresponding author at: Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan. Tel.: +81 88 633 7207; fax: +81 88 633 7208. E-mail address: [email protected] Ryuji Kaji Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Available online 6 November 2014
Contents lists available at ScienceDirect
Clinical Neurophysiology journal homepage: www.elsevier.com/locate/clinph
Letter to the Editor Ultrasonographic discharges
evaluation
of
myokymic
See Editorial, pages 1466–1467 Myokymic discharges are a group of motor unit action potentials that fire repetitively (Kimura, 2013). The etiologies for limb myokymic discharges include radiation-induced plexopathy, myelopathy, multiple sclerosis, inflammatory polyradiculopathy, ischemic neuropathy, inflammatory neuropathy, peripheral nerve hyperexcitability and other chronic disorders of the spinal cord and peripheral nerves (Albers et al., 1981). Myokymic discharges commonly accompany clinical myokymia (defined as a fine persistent quivering or rippling of muscles). Recent advent of neuromuscular sonography has shed light on pathological movements caused by neuromuscular diseases. Electro-sonographic correlation has been reported in fasciculation and possible fibrillations (Pillen et al., 2009; Reimers et al., 1996; Walker et al., 1990). Here, to characterize sonographic appearance of myokymic discharges, we present a simultaneous recording of myokymic discharges and sonographic images of muscle contraction. A 69-year-old man complained about gait disturbance since age 65. Clinical examination revealed features of length-dependent sensorimotor dysfunction (e.g., weakness, muscle atrophy, sensory loss), autonomic failure, and myokymia in his left arm. Nerve conduction studies revealed severe sensorimotor axonal polyneuropathy. Needle electromyography revealed evidence of diffuse active denervation, reinnervation, and myokymic discharges in the left biceps, which were further characterized by concurrent ultrasonography (Fig. 1 and Video 1). Ultrasonography showed repetitive, brief but sustained, tractive movements of the surface of the muscle occurring slightly after the onset of the myokymic discharges. Genetic testing revealed a heterozygous mutation (Val30Met) in the TTR gene, confirming the diagnosis of familial amyloid polyneuropathy. To the authors’ knowledge, simultaneous recording of myokymic discharges and myokymia has not been reported. Myokymia in the present patient differed from fasciculation because fasciculation appears as short jerky movements occurring irregularly and randomly in different areas of the muscles (Video 2). Of note, sonography might have greater sensitivity than visual inspection for detection of myokymia because of the ability to visualize deep muscle tissues by sonography, although future study should elucidate the point. In addition, due to the non-invasiveness of sonography, sonographic screen for suspicious muscle contractions would be confirmed by ‘‘echo-guided’’ needle EMG, which could result in a smaller number of needle insertion than unguided needle EMG proce-
dure to detect diagnostic electrical discharges. Thus, muscle sonography can play an indispensable role in the detection and characterization of abnormal, but potentially similar muscle movements such as rippling muscles. Interestingly, some of the myokymic discharges correlated with the patient’s inspiration, especially in the initial part of Video 1. It is possible that respiratory drive triggered firing of the myokymic discharges due to aberrant reinnervation, as reported in ‘‘breathing arm syndrome’’ (Lam and Engstrom, 2010; Swift et al., 1980). However, we regret that respiration was not monitored during the recording and the potential relationship between the myokymic discharges and respiration was unable to be further elucidated. Given the firing rate greater than 50 per minute shown in the EMG screen near the end of the Video 1 and the lack of clinical tachypnea, respiratory drive might have triggered myokymic discharges at least in the initial part of the video, when the firing and the respiratory rates were similar. Conflict of Interest None of the authors have potential conflicts of interest to be disclosed.
Fig. 1. Concurrent recording of the muscle contraction in the left biceps brachii by needle electromyography and ultrasonography.
http://dx.doi.org/10.1016/j.clinph.2014.10.154 1388-2457/Ó 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Letter to the Editor / Clinical Neurophysiology 126 (2015) 1638–1639
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.clinph.2014.10. 154. References Albers JW, Allen 2nd AA, Bastron JA, Daube JR. Limb myokymia. Muscle Nerve 1981;4:494–504. Kimura J. Electrodiagnosis in diseases of nerve and muscle: principles and practice. New York, USA: Oxford University Press; 2013. Lam L, Engstrom J. Teaching video NeuroImages: the breathing arm: respiratory brachial synkinesis. Neurology 2010;74:e69. Pillen S, Nienhuis M, van Dijk JP, Arts IM, van Alfen N, Zwarts MJ. Muscles alive: ultrasound detects fibrillations. Clin Neurophysiol 2009;120:932–6. Reimers CD, Ziemann U, Scheel A, Rieckmann P, Kunkel M, Kurth C. Fasciculations: clinical, electromyographic, and ultrasonographic assessment. J Neurol 1996;243:579–84. Swift TR, Leshner RT, Gross JA. Arm-diaphragm synkinesis: electrodiagnostic studies of aberrant regeneration of phrenic motor neurons. Neurology 1980;30:339–44. Walker FO, Donofrio PD, Harpold GJ, Ferrell WG. Sonographic imaging of muscle contraction and fasciculations: a correlation with electromyography. Muscle Nerve 1990;13:33–9.
Yusuke Osaki Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Naoko Takamatsu Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan
1639
Yoshimitsu Shimatani Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Atsuko Mori Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Keiko Maruyama Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Yoshimichi Miyazaki Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan
⇑
Hiroyuki Nodera Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan ⇑ Corresponding author at: Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan. Tel.: +81 88 633 7207; fax: +81 88 633 7208. E-mail address: [email protected] Ryuji Kaji Department of Clinical Neuroscience, Institute of Health Biosciences, Tokushima University, Tokushima, Japan Available online 6 November 2014
