Background: The neuroanatomic substrate of restless legs syndrome (RLS) is poorly understood, and the diagnosis is clinically made based upon subjective sensory symptoms, although a motor component is usually present. Case Report: We report two cases of elderly patients with spinal pathology who were referred by neurologists for myoclonus. Both had semi-rhythmic leg movements that partially improved while standing, but denied any urge to move. These movements improved dramatically with pramipexole, a dopamine agonist used for RLS. Discussion: We propose that this "myoclonus" is actually the isolated stereotypic motor component of RLS

Ondo, William G.

Tremor and Other Hyperkinetic Movements

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Background: The neuroanatomic substrate of restless legs  syndrome (RLS) is poorly understood, and the diagnosis is clinically  made based upon subjective sensory symptoms, although a motor component  is usually present. Case Report: We report two cases of elderly patients with  spinal pathology who were referred by neurologists for myoclonus. Both  had semi-rhythmic leg movements that partially improved while standing,  but denied any urge to move. These movements improved dramatically with  pramipexole, a dopamine agonist used for RLS. Discussion: We propose that this &ldquo;myoclonus&rdquo; is actually the isolated stereotypic motor component of RLS.</div

William G. Ondo

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Movements Mimicking Myoclonus Associated with Spinal Cord Pathology: Is this a "Pure Motor Restless Legs Syndrome"?

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Case ReportMovements Mimicking Myoclonus Associated with Spinal Cord Pathology:Is this a ‘‘Pure Motor Restless Legs Syndrome’’?William G. Ondo1*1University of Texas Health Science Center at Houston, Houston, TX 77025, United States of AmericaAbstractBackground: The neuroanatomic substrate of restless legs syndrome (RLS) is poorly understood, and the diagnosis is clinically made based upon subjectivesensory symptoms, although a motor component is usually present.Case Report: We report two cases of elderly patients with spinal pathology who were referred by neurologists for myoclonus. Both had semi-rhythmic legmovements that partially improved while standing, but denied any urge to move. These movements improved dramatically with pramipexole, a dopamine agonistused for RLS.Discussion: We propose that this ‘‘myoclonus’’ is actually the isolated stereotypic motor component of RLS.Keywords: Restless legs syndrome, myoclonus, dopamine agonists, periodic limb movements, dyskinesia while awakeCitation: Ondo WG. Movements mimicking Myoclonus associated with spinal cord pathology : Is this a ‘pure motor restless legs syndrome’? Tremor OtherHyperkinet Mov 2012;2: http://tremorjournal.org/article/view/34* To whom correspondence should be addressed. E-mail: William.Ondo@uth.tmc.eduEditor: Elan D. Louis, Columbia UniversityUnited States of AmericaReceived: May 8, 2011 Accepted: June 23, 2011 Published: March 20, 2012Copyright: ’ 2012 Ondo. This is an open-access article distributed under the terms of the Creative Commons Attribution–Noncommercial–No Derivatives License, which permits theuser to copy, distribute, and transmit the work provided that the original author(s) and source are credited; that no commercial use is made of the work; and that the work is not altered ortransformed.Funding: None.Competing Interests: WGO is Speaker and consultant for GSK, BI, TEVA, Allergan, Ipsen, Lundbeck.IntroductionRestless legs syndrome (RLS) is clinically defined by the presence offour clinical features: 1) an urge to move the limbs with or withoutsensations; 2) worsening at rest; 3) improvement with activity; 4)worsening in the evening or night.1 Periodic limb movements duringsleep (formerly called nocturnal myoclonus)2 accompany RLS in mostcases.3 Wakeful movements, variably called dyskinesia while awake orperiodic limb movements while awake, are also seen in some cases.4These movements are often considered the ‘‘motor’’ component ofRLS, whereas the urge to move is the ‘‘sensory’’ component. Thatsaid, no criteria for partial RLS in subjects partially meeting the fourcardinal features for RLS exist, nor has a syndrome of an isolatedmotor component of RLS without the required sensory componentbeen formally described.Myoclonus is a heterogeneous group of conditions, basically definedas brief (,0.25-second) jerks. Classifications have developed that arepredicated on the anatomy of the movements, the rhythmicity, thepresumed neuroanatomy of physiological origin, and electrophysiolo-gic criteria. We report two cases that may represent the isolated motorcomponent of RLS, misdiagnosed as myoclonus by referringneurologists, in the setting of spinal cord pathology.Case reportCase #1This 80-year-old right-handed male presented with leg jerking and adiagnosis of myoclonus. He reports that the leg jerking beganindolently approximately 4 years prior to our evaluation; however, itbecame quite severe within the past 4 months. It worsens when he isseated or reclined and partially improves while standing or walking.The patient has these constantly, every few seconds, and theysignificantly impair his ability to sleep, sit comfortably, and ambulate.He absolutely denied any sort of urge to move or premonitorysensation. There is no family history of RLS.The patient had a long history of both cervical and lumbar spinaldisease and previously has underdone two cervical and two lumbarsurgeries. He continues to suffer from debilitating lumbar and cervicalpain but does not correlate the movements with any pain. He has triedseveral medicines; most recently, clonazepam 2 mg, which helpedFreely available onlineTremor and Other Hyperkinetic Movementshttp://www.tremorjournal.orgThe Center for Digital Research and ScholarshipColumbia University Libraries/Information Services1slightly. The patient had a spinal cord stimulator and an implantablepain pump with morphine and clonidine. Neither of these altered theinvoluntary movements but did modestly improve pain.Examination was normal except for decreased leg sensation tolight touch, and vibration in the feet most consistent with either aneuropathy or L5/S1 radiculopathy, and absent leg reflexes. His gaitwas both antalgic and mildly wide-based. The involuntary movementswere an almost constant, semi-rhythmic, quick, predominantly legabduction movements at the hip, which were generally symmetric(Video Segment 1A). These did lessen when standing and stoppedwhile walking.The patient was placed on pramipexole 0.25 mg q.h.s. and titratedup to 0.5 mg three times a day. He reported almost complete resolutionof the leg jerking subjectively and on subsequent examination, andmoderate improvement in pain. His examination was otherwiseunchanged. (Video Segment 1B). There were no adverse events.The patient subsequently tapered off all benzodiazepines andreduced oral narcotics by 50%. He has successfully maintainedtherapy with .95% improvement in movements but some return ofthe chronic low back pain for more than 24 months.Case #2This 86-year-old right-handed Caucasian female presented with legjerking, diagnosed as myoclonus. Approximately 10 years ago, she hadexperienced acute thoracic pain diagnosed as spinal compression withruptured discs at T8 and T10. Gait was markedly impaired secondaryto pain and weakness but she gradually regained the ability toambulate. One to 2 years after this incident she began having theinsidious onset of jerkiness in her legs. These gradually worsened andin the past 3 years has been quite severe, occurring hundreds of timesthroughout the day with some nocturnal intensification. They partiallyimprove while standing or walking but are still subjectively present andinterfere with her gait. She specifically denies any urge to move orsensory component, and is unaware of any rhythmicity. There is nofamily history of RLS. The patient had an extensive workup and hastried more than 20 medications for the movements.She had mild cognitive impairment (mini-mental status examination(MMSE) 24/30). Sensation showed mild decreased vibration sense inCase 1: Before TreatmentVideo Segment 1A. The patient shows semi-rhythmic abduction/adductionmovements at the hip that improve upon standing.Case 1: After TreatmentVideo Segment 1B. The patient from Segment 1 at initial follow-up.Movements are markedly diminished in amplitude and intensity. Subsequentexaminations showed no movements.Case 2Video Segment 2. The patient shows leg abduction/adduction movements andhip flexion movements that improve while standing. Visualization of themovements in this video is brief but identical movements were seen constantlythroughout the evaluation prior to treatment.Video Segment 1AVideo Segment 2Video Segment 1BOndo WG Movements Mimicking Myoclonus Associated with Spinal Cord PathologyTremor and Other Hyperkinetic Movementshttp://www.tremorjournal.orgThe Center for Digital Research and ScholarshipColumbia University Libraries/Information Services2both feet. She did have some stooped posture, slow, modestly wide-basedgait, and was unable to tandem walk. Reflexes were 0 in the anklesand 1/4 elsewhere with downgoing toes. The involuntary movementwas predominantly adduction/adduction of the legs at the hips,which occurred at a frequency of approximately 1 Hz (VideoSegment 2). She also had hip flexion associated with truncal flexioninterspersed with the adduction/abduction. This would largelydissipate when standing.The patient was placed on pramipexole, which was titrated up to0.5 mg three times a day. She reported complete cessation of themovements without adverse events. Post-treatment examinationshowed no movements. Her sleep was much better, and mood wassubsequently improved. She has continued good response for morethan a year.DiscussionThese two similar cases (large amplitude, involuntary symmetric legmovements without urge, gradually developing in the setting of spinalpathology) could represent the isolated physiologic motor componentof RLS. The pathophysiology of RLS is not understood but descendingspinal dopaminergic tracts have been postulated to be involved in bothRLS and periodic limb movements (often considered the motorcomponent of the syndrome).5,6 Spinal cord injuries have also beenreported to be associated with RLS and especially periodic limbmovements of sleep.7 However, it should be emphasized that thesecases do not meet criteria for RLS, and both were diagnosed asmyoclonus by other neurologists. ‘‘Dyskinesia while awake’’ is an olderterm in the RLS literature used to describe wakeful stereotype, usuallyankle dorsi/plantar flexion, is also seen in typical RLS but is distinctfrom this. There is no way to physiologically or pathologically prove adiagnosis of pure motor RLS but the dramatic response topramipexole is very suggestive. Periodic limb movements (motorcomponent) respond more dramatically to dopaminergics than toother treatments used for RLS. Myoclonus is of a shorter duration andusually less complex than these movements. If one insists on calling thisphenomenology myoclonus, then it should be emphasized that adopamine agonist completely controlled the movements whennumerous medicines typically tried for myoclonus did not help.References1. Allen RP, Picchietti D, Hening WA, et al. Restless legs syndrome:diagnostic criteria, special considerations, and epidemiology. A report from therestless legs syndrome diagnosis and epidemiology workshop at the NationalInstitutes of Health. Sleep Med 2003;4:101–119, http://dx.doi.org/10.1016/S1389-9457(03)00010-8.2. Lugaresi E, Cirignotta F, Coccagna G, et al. Nocturnal myoclonus andrestless legs syndrome. Advanc Neurol 1986;43:295–307.3. Montplaisir J, Boucher S, Poirier G, et al. Clinical, polysomnographic,and genetic characteristics of restless legs syndrome: a study of 133 patientsdiagnosed with new standard criteria. Mov Disord 1997;12:61–65, http://dx.doi.org/10.1002/mds.870120111.4. Walters AS, Hening WA, Chokroverty S. Frequent occurrence ofmyoclonus while awake and at rest, body rocking and marching in place in asubpopulation of patients with restless legs syndrome. Acta Neurolog Scand 1988;77:418–421, http://dx.doi.org/10.1111/j.1600-0404.1988.tb05929.x.5. Bara-Jimenez W, Aksu M, Graham B, et al. Periodic limb movements insleep: state-dependent excitability of the spinal flexor reflex. Neurology 2000;54:1609–1616.6. Qu S, Le W, Zhang X, et al. Locomotion is increased in a 11-lesionedmice with iron deprivation: a possible animal model for restless legs syndrome.J Neuropathol Exp Neurol 2007;66:383–8, http://dx.doi.org/10.1097/nen.0b013e3180517b5f.7. Winkelmann J, Wetter TC, Trenkwalder C, et al. Periodic limbmovements in syringomyelia and syringobulbia. Mov Disord 2000;15:752–753,http://dx.doi.org/10.1002/1531-8257(200007)15:4,752::AID-MDS1029.3.0.CO;2-Q.Movements Mimicking Myoclonus Associated with Spinal Cord Pathology Ondo WGTremor and Other Hyperkinetic Movementshttp://www.tremorjournal.orgThe Center for Digital Research and ScholarshipColumbia University Libraries/Information Services3

Movements Mimicking Myoclonus Associated with Spinal Cord Pathology: Is This a "Pure Motor Restless Legs Syndrome"?

Frequent occurrence of myoclonus while awake and at rest, body rocking and marching in place in a subpopulation of patients with restless legs syndrome. Acta Neurolog Scand

Locomotion is increased in a 11-lesioned mice with iron deprivation: a possible animal model for restless legs syndrome. JN e u r o p a t h o lE x pN e u r o l2007;66:383–8,

Movements Mimicking Myoclonus Associated with Spinal Cord Pathology Ondo

Nocturnal myoclonus and restless legs syndrome. Advanc Neurol

Periodic limb movements in sleep: state-dependent excitability of the spinal flexor reflex.

Periodic limb movements in syringomyelia and syringobulbia.

polysomnographic, and genetic characteristics of restless legs syndrome: a study of 133 patients diagnosed with new standard criteria. Mov Disord 1997;12:61–65,

Restless legs syndrome: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2003;4:101–119,

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Movements Mimicking Myoclonus Associated with Spinal Cord Pathology: Is This a "Pure Motor Restless Legs Syndrome"?

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