Neurology International 2009; volume 1:e2

Focal dystonia, Twenty days later, neurological evaluation revealed very limited voluntary and passive Correspondence: Konstantina G. Yiannopoulou, and myokymic discharges movement of the right leg which caused an Vas. Tsounia 12A, 11526, Maroussi, Athens, secondary to electrical injury inability to flex the knee. Both voluntary and Greece. E-mail: [email protected] passive movements resulted in excruciating Key words: focal dystonia, tremor, myokymic Konstantina G. Yiannopoulou,1 pain and tremor of the right lower limb. discharges, electrical injury Theodoros Avramidis,2 Roxani Divari,2 Examination revealed an intact mental status. Alexandros Papadimitriou3 Cranial nerves were intact. Motor examination Received for publication: 28 January 2009. of the other 3 limbs was normal. Revision received: 19 March 2009. 1Department of Neurology, Laiko General Accepted for publication: 24 April 2009. He received diazepam and carbamazepine Hospital, Athens, Greece; with no response. Botulinum toxin A procedure This work is licensed under a Creative Commons 2Department of Neurology, Red Cross was considered painful and was not tolerated by Attribution 3.0 License (by-nc 3.0) Hospital, Athens, Greece; the patient. 3 ©Copyright K.G. Yiannopoulou et al., 2009 Department of Neurology, University of Three years later his right leg was markedly Thessalia, Larissa, Greece Licensee PAGEPress, Italy extended at the knee and every attempt to flex it Neurology International 2009; 1:e2 caused coarse tremor and painful muscle con- doi:10.4081/ni.2009.e2 tractions of the whole limb. Atrophy of the right quadriceps was noticed. He was trying to walk Abstract with the leg always extended in order to avoid Discussion tremor and pain. His situation remained We describe the case of a male patient who unchanged throughout all these years, but he A PubMed search revealed only 10 cases of developed electromyographically confirmed did not stop working as an office clerk. dystonia and/or tremor (Table 1) secondary to myokymia, dystonia and tremor and clinically He had no previous medical problems. There electrical injury. Only one of them is described confirmed focal dystonia and tremor, secondary was no history of head trauma, systemic dis- exclusively as tremor and another as tremor to electrical injury. Dystonia is a rare complica- eases, nor exposure to neuroleptic drugs. Family and dystonia simultaneously. The 8 remaining tion of electrical injury. Myokymic discharges history of movement disorders was also nega- only cases are reported to suffer exclusively from secondary to electrical injury are previously tive. unreported. Dystonia and tremor EMG findings Routine laboratory tests, brain and spinal dystonia. Our case is the only one with dysto- were present not only at the clinically affected magnetic resonance imaging (MRI) were un- nia, tremor and myokymia coexistence, and muscles of the lower limb but also at the clini- remarkable. usethe first one that presents myokymia as sec- cally unaffected upper limb muscles. This is the Nerve conduction studies were normal. ondary complication of an electrical injury. first case report to link myokymia as a second- EMG recordings did not show neuropathic or Additionally, it is the only case with lower limb ary complication of an electrical injury. myopathic changes but did reveal that: involvement. The previous reports include lin- a) knee flexion produced continuous muscle gual involvement (2 cases), upper limb involve- fiber activity of high frequency, simultaneously ment (5 cases) and torticollis (2 cases). It is in agonist and antagonist muscles of the right also interesting that dystonia and tremor EMG Introduction limbs. At the same time, a painful lower limb findings in our patient were present not only at muscle was observed. The above pat- the clinically affected muscles of the lower limb Electrical injury as a cause of movement dis- terns, indicative of dystonia, were stable for sev- but also at the clinically unaffected ipsilateral order is rare and is even less frequent as a eral minutes;1 upper limb muscles. EMG findings in the previ- cause of dystonia.1 Electrical injury as a cause b) immediately afterwards, a 10Hz bursting ous cases are reported to be present only in the of myokymic discharges has not been previ- pattern of motor unit action potentials with high clinically affected part of the body. ously reported.2 We describe the case of a amplitude and separated by relative silence was Electrical injury occurs when a portion of patient who developed electromyographically observed; it was produced in an alternating the body completes an electrical circuit. confirmed myokymia, dystonia and tremor and fashion between flexors and extensors of the Damage occurs as a result of tissue sensitivity clinically confirmed focal dystonia and tremor, right upper and lower extremity (Figure 1a). to thermal injury and electroporation, a term secondary to electrical injury. Non-commercialThis activity with tremor morphology 1 was describing non-thermal damage to cell mem- accompanied by a high range tremor of 3-4 min- branes as a result of electricity.3 Electrical utes duration only in the lower-right extremity; injury can result in damage to both the periph- c) another spontaneous activity, indicative of eral and central nervous system.4,5 Several dif- Case Report myokymic discharges2 was observed at rest in ferent types of movement disorders after elec- the right deltoid (Figure 1b), but also in the trocution have been reported, including torti- A 29-year old male was referred to the emer- supraspinatus, trapezius and paraspinal mus- collis, limb and lingual dystonia, tremor and gency room because of electrocution. He had cles, consisting of grouped motor potentials fir- Parkinsonism.1,6-13 grasped one end of a live electrical cable with ing at 8Hz continuously with 2-4 units within a Dystonia is a rare complication of electrical his right hand, he received a severe electrical burst. injury: only 8 cases of dystonia secondary to shock throwing him 2 meters backward, he lost Distraction with physical (contralateral fin- electrical injury have been published,1,6-9,12,13 consciousness without seizures, according to ger tapping) or mental activities (counting, while in two large studies with a total of 272 witnesses, and immediately afterwards he singing) did not alter any of the above described cases of electrical injury, no patient developed reported limited motion and numbness of the activities. The same EMG patterns were repro- dystonia.14,15 The pathophysiology of electrical- right extremities. An emergency room evalua- duced in a stereotyped manner by repeating the ly induced dystonia remains highly specula- tion that day found no objective abnormality flexion maneuver at the knee. tive but is widely considered to be a type of apart from two small electrical burns on his There was no abnormal activity seen in the trauma-induced .9 Post- right hand and foot. left extremities. traumatic dystonia occurs after both central

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and peripheral lesions. Some researchers a have postulated an underlying genetic predis- position, previous neural damage, or prior drug exposure. Pathophysiological theories advocate direct damage to the nervous sys- tem, as well as a variety of delayed indirect effects, including aberrant neuronal sprout- ing, denervation supersensitivity, ephaptic transmission, and oxidative reactions. Proposed criteria for a peripherally induced movement disorder are: (a) sufficient severi- ty of the injury, (b) anatomic relationship between the injury site and the site of onset of the movement disorder and (c) a latent period b of less than one year between the injury and the subsequent disease.16 Our case fulfills these criteria in that our patient suffered a severe electrical injury, the latency between the injury and the onset of symptoms was 20 days, and the symptomatic leg was the leg which had received the injury. Although a diagnosis of psychogenic dystonia was consid- ered, the stereotyped nature of the movement disorder and lack of variability on clinical and EMG evaluation support an organic disorder thatonly was temporally-related to an electrical injury. The patient was never witnessed to be free of symptoms when left alone, despite hav- Figure 1. (a) EMG-right arm: motor unit grouping with a frequency of 10Hz in an alter- ing this problem for many years. There was no nating pattern between flexors and extensors (tremor). (b) EMG-right arm: spontaneoususe inconsistency in his disorder, nor did we feel discharges firing at 8Hz with 2-4 units within a burst (myokymic discharges) in the right there was incongruity with a diagnosis of deltoid muscle (top recording). No findings in the left deltoid muscle (bottom recording). symptomatic, organic dystonia. He underwent repetitive EMG studies, with reproducibility and a lack of variability or distraction. There were no other neurological signs suggesting psychogenicity, nor any somatizations or psy- Table 1. Dystonia or/and tremor after electrical injury in the literature. chiatric disturbances. Article Movement Number of Special Myokymic discharges secondary to electrical disorder cases reported features injury, have not, to our knowledge, been report- ed. Other causes of focal myokymia including Torticollis after Dystonia 1 Torticollis/responded to botulinum Guillain-Barré syndrome, , 6 electrocution toxin injections radiation plexopathy, pontine tumors, mening- Limb dystonia following Dystonia 3 Upper extremity/botulinum toxin oradiculitis, syringobulbia and hypothyroidism 7 electrical injury injections, in two of the patients, were ruled out.2,17-18 Since electrical injury can mainly improved passive movements affect both the upper and lower motor neu- Case of torticollis occurring Dystonia 1 Torticollis/responded to botulinum rons,5 it seems to be the most likely origin of 8 following electrical injury tremorNon-commercialtoxin injections these EMG-recorded myokymic discharges. We Dystonia secondary to Dystonia 1 Upper extremity/some improvement suggest that the local myokymic discharges in electrical injury: surface tremor with botulinum toxin/finally amputation our patient were produced by a mechanism electromyographic evaluation of the arm because of the pain similar to that of irradiation-induced cases,18 and implications for the since this is the only external triggering factor 1 organicity of the condition correlated to the local form of this spontaneous Lingual dystonia Dystonia 1 activity. Myokymia is a disorder of the motor 9 following electrical injury unit. Its underlying cause probably involves a Focal lingual dystonia, urinary Dystonia 1 Lingual dystonia/resolved biochemical alteration of the microenviron- incontinence, and sensory with botulinum toxin injections ment or the membrane of the motor axon. In a deficits secondary to low number of instances, abnormalities of voltage voltage electrocution: case gated K+ channels (VGKC) have been docu- report and literature review13 mented.2 The source of generation of Tongue tremor in a patient Tremor 1 Tongue tremor/transient/coma myokymic discharge (the ectopic generator) with coma after may be at one or more lesioned segments on electrical injury11 the motor axon, may be further supported by Segmental dystonia following Dystonia 1 Upper extremity ephaptic transmission or antidromic stimula- 12 electrocution in childhood tion mechanisms and with the nature of the

[Neurology International 2009; 1:e2] [page 5] Case Report underlying disease process. Although radiation the hand. Mov Disord 1998;13:600-2. is often an associated cause for myokymic dis- References 11. Lin K, Lin J, Piovesan EJ, et al. Tongue charges, other factors that can irritate the tremor in a patient with coma after electri- motor axon and produce myokymia include 1. Adler CH, Caviness JN. Dystonia second- cal injury. Mov Disord 2003;18:834-6. demyelination, autoimmune processes, genet- ary to electrical injury: surface electromyo- 12. Lim EC, Seet RC. Segmental dystonia fol- ic determination, toxic effects, ischemia, graphic evaluation and implications for lowing electrocution in childhood. Neurol Sci 2007;28:38-41. hypoxia, and edema.2 Myokymic discharges are the organicity of the condition. Neuro Sci 13. Baskerville JR, McAninch SA. Focal lingual thought to represent axonal hyperexcitability, 1997;148:187-92. 2. Gutmann L, Gutmann L. Myokymia and dystonia, urinary incontinence, and senso- either due to spontaneous depolarization or to 2004. Neuro 2004;251:138- ry deficits secondary to low voltage electro- ephaptic transmission from surrounding 42. cution: case report and literature review. nerves. The discharges are short bursts of sin- 3. Chen W, Lee RC. Evidence for electrical Emerg Med J 2002;19:368-71 gle motor unit action potentials at individual shock-induced conformation damage of 14. Butler ED, Gant TD. Electrical injuries, discharge frequencies of 5-150 Hz that can voltage-gated ionic channels. Ann NY Acad with special reference to the upper occur in isolation or as multiplets. Burst dura- Sci 2004;720:124-35. extremities: A review of 182 cases. Am J tions typically range from 100 to 1,000 millisec- 4. Wilbourn AJ. Peripheral nerve disorders in Surg 1977;134:95-101. onds. Group discharge frequencies usually electrical and lightning injuries. Semin 15. Grube BJ, Heimbach DM, Engrav LH, occur between 1 and 5 Hz but may be slower Neurol 1995;15:241-55. Copass MK. Neurologic consequences of and may also be variable at times. When con- 5. Cherington M. Central nervous system electrical burns. J Trauma 1990;30:254-8. tinuous, the group discharge frequency is complications of lightning and electrical 16. Jankovic J. Post-traumatic movement dis- often dependent on the length of the burst injuries. Semin of Neurol 1995;15: 233-40. orders: central and peripheral mecha- duration, with longer bursts firing less often.19 6. Colosimo C, Kocen RS, Powell M, et al. nisms. Neurology 1994;44:2006-14. Our case is the only one with dystonia, Torticollis after electrocution. Mov Disord 17. Lo YL, Ho SC, Koh LK, Khoo DH. EMG myokymia as a cause of ptosis in hypothy- tremor and myokymia coexistence and the 1993;18: 117-8. 7. Tarsy D, Sudarsky L, Charness E. Limb dys- roidism. Eur Neurol 2003;10: 87-90. first one that presents myokymia as a second- tonia following electrical injury. Mov 18. Harperonly MC, Thomas JE, Cascino TL, Litchy ary complication of an electrical injury. Disord 1994;9:230-2. WJ. Distinction between neoplastic and Additionally, it is the only case with lower limb 8. Boonkongchuen P, Lees A. Case of torticol- radiation-induced brachial plexopathy, dystonia and tremor after electrocution. It is lis following electrical injury. Mov Disord with emphasis on the role of EMG. also interesting, that dystonia and tremor EMG 1996;11:109-10. use Neurology 1989;39:502-6. findings in our patient were present not only at 9. Ondo W. Lingual Dystonia following elec- 19. Richardson RC, Weiss MD. Unilateral the clinically affected muscles of the lower trical injury. Mov Disord 1997;12:253. myokymia of the tongue after radiation limb but also at the clinically unaffected ipsi- 10. Morris HR, Moriabadi NF, Lees AJ, et al. therapy for cervical nodal melanoma. J lateral upper limb muscles. Parkinsonism following electrical injury to Clin Neuromuscul Dis 2009;10:122-5.

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