Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Symptomatic (secondary) myoclonus

John N Caviness, MD
Section Editor
Howard I Hurtig, MD
Deputy Editor
John F Dashe, MD, PhD


Myoclonus is a clinical sign that is characterized by brief, shock-like, involuntary movements caused by muscular contractions or inhibitions [1]. Muscular contractions produce positive myoclonus, whereas muscular inhibitions produce negative myoclonus (ie, asterixis). Patients will usually describe myoclonus as consisting of "jerks," "shakes," or "spasms."

Myoclonic movements have many possible etiologies, anatomic sources, and pathophysiologic features [2]. Myoclonus may be classified by clinical presentation, examination findings, clinical neurophysiology testing, and etiology.

This topic will discuss disorders associated with symptomatic (secondary) myoclonus. Other aspects of myoclonus are reviewed separately. (See "Classification and evaluation of myoclonus" and "Treatment of myoclonus".)


The classification scheme of Marsden and colleagues uses four major categories to organize the numerous etiologies of myoclonus (table 1) [1]:


To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Oct 2017. | This topic last updated: Sep 27, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Marsden CD, Hallett M, Fahn S. The nosology and pathophysiology of myoclonus. In: Movement Disorders, Marsden CD, Fahn S (Eds), Butterworths, London 1982. p.196.
  2. Caviness JN. Myoclonus. Mayo Clin Proc 1996; 71:679.
  3. Caviness JN, Alving LI, Maraganore DM, et al. The incidence and prevalence of myoclonus in Olmsted County, Minnesota. Mayo Clin Proc 1999; 74:565.
  4. Shahwan A, Farrell M, Delanty N. Progressive myoclonic epilepsies: a review of genetic and therapeutic aspects. Lancet Neurol 2005; 4:239.
  5. Marsden CD, Harding AE, Obeso JA, Lu CS. Progressive myoclonic ataxia (the Ramsay Hunt syndrome). Arch Neurol 1990; 47:1121.
  6. Borg M. Symptomatic myoclonus. Neurophysiol Clin 2006; 36:309.
  7. Caviness JN. Myoclonus and neurodegenerative disease--what's in a name? Parkinsonism Relat Disord 2003; 9:185.
  8. Caviness JN, Adler CH, Beach TG, et al. Small-amplitude cortical myoclonus in Parkinson's disease: physiology and clinical observations. Mov Disord 2002; 17:657.
  9. Caviness JN, Adler CH, Caselli RJ, Hernandez JL. Electrophysiology of the myoclonus in dementia with Lewy bodies. Neurology 2003; 60:523.
  10. Caviness JN, Gwinn-Hardy K, Adler CH, Muenter MD. Electrophysiological observations in hereditary parkinsonism-dementia with Lewy body pathology. Mov Disord 2000; 15:140.
  11. Caviness JN, Adler CH, Beach TG, et al. Myoclonus in Lewy body disorders. Adv Neurol 2002; 89:23.
  12. Brunt ER, van Weerden TW, Pruim J, Lakke JW. Unique myoclonic pattern in corticobasal degeneration. Mov Disord 1995; 10:132.
  13. Thompson PD, Shibasaki H. Myoclonus in corticobasal degeneration and other neurodegenerations. Adv Neurol 2000; 82:69.
  14. Thompson PD, Day BL, Rothwell JC, et al. The myoclonus in corticobasal degeneration. Evidence for two forms of cortical reflex myoclonus. Brain 1994; 117 ( Pt 5):1197.
  15. Kurihara T, Landau WM, Torack RM. Progressive supranuclear palsy with action myoclonus, seizures. Neurology 1974; 24:219.
  16. Wenning GK, Ben Shlomo Y, Magalhães M, et al. Clinical features and natural history of multiple system atrophy. An analysis of 100 cases. Brain 1994; 117 ( Pt 4):835.
  17. Gouider-Khouja N, Vidailhet M, Bonnet AM, et al. "Pure" striatonigral degeneration and Parkinson's disease: a comparative clinical study. Mov Disord 1995; 10:288.
  18. Rodriguez ME, Artieda J, Zubieta JL, Obeso JA. Reflex myoclonus in olivopontocerebellar atrophy. J Neurol Neurosurg Psychiatry 1994; 57:316.
  19. Artieda J, Obeso JA. The pathophysiology and pharmacology of photic cortical reflex myoclonus. Ann Neurol 1993; 34:175.
  20. Caviness JN, Wszolek ZK. Myoclonus in pallido-ponto-nigral degeneration. Adv Neurol 2002; 89:35.
  21. Bugiani O, Murrell JR, Giaccone G, et al. Frontotemporal dementia and corticobasal degeneration in a family with a P301S mutation in tau. J Neuropathol Exp Neurol 1999; 58:667.
  22. Caviness JN, Kurth M. Cortical Myoclonus in Huntington's disease associated with an enlarged somatosensory evoked potential. Mov Disord 1997; 12:1046.
  23. Warner TT, Williams LD, Walker RW, et al. A clinical and molecular genetic study of dentatorubropallidoluysian atrophy in four European families. Ann Neurol 1995; 37:452.
  24. Afzal A, Ashraf S, Shamim S. Opsoclonus myoclonus syndrome: an unusual presentation for West Nile virus encephalitis. Proc (Bayl Univ Med Cent) 2014; 27:108.
  25. Tan KM, Lennon VA, Klein CJ, et al. Clinical spectrum of voltage-gated potassium channel autoimmunity. Neurology 2008; 70:1883.
  26. Deconinck N, Scaillon M, Segers V, et al. Opsoclonus-myoclonus associated with celiac disease. Pediatr Neurol 2006; 34:312.
  27. Caviness JN, Forsyth PA, Layton DD, McPhee TJ. The movement disorder of adult opsoclonus. Mov Disord 1995; 10:22.
  28. Gwinn KA, Caviness JN. Electrophysiological observations in idiopathic opsoclonus-myoclonus syndrome. Mov Disord 1997; 12:438.
  29. Bhatia KP, Brown P, Gregory R, et al. Progressive myoclonic ataxia associated with coeliac disease. The myoclonus is of cortical origin, but the pathology is in the cerebellum. Brain 1995; 118 ( Pt 5):1087.
  30. Stoupel N, Monseu G, Pardoe A, et al. Encephalitis with myoclonus in Whipple's disease. J Neurol Neurosurg Psychiatry 1969; 32:338.
  31. Henning S, Tings T, Schmidt H, et al. A case of cerebral Whipple's disease initially presenting with isolated focal myoclonus. Eur J Neurol 2006; 13:659.
  32. Schwartz MA, Selhorst JB, Ochs AL, et al. Oculomasticatory myorhythmia: a unique movement disorder occurring in Whipple's disease. Ann Neurol 1986; 20:677.
  33. Wierre L, Decaudin B, Barsumau J, et al. Dobutamine-induced myoclonia in severe renal failure. Nephrol Dial Transplant 2004; 19:1336.
  34. Zhang C, Glenn DG, Bell WL, O'Donovan CA. Gabapentin-induced myoclonus in end-stage renal disease. Epilepsia 2005; 46:156.
  35. Caviness JN, Truong DD. Myoclonus. Handb Clin Neurol 2011; 100:399.
  36. Gordon MF. Toxin and drug-induced myoclonus. Adv Neurol 2002; 89:49.
  37. Jiménez-Jiménez FJ, Puertas I, de Toledo-Heras M. Drug-induced myoclonus: frequency, mechanisms and management. CNS Drugs 2004; 18:93.
  38. Mirsattari SM, Hammond RR, Sharpe MD, et al. Myoclonic status epilepticus following repeated oral ingestion of colloidal silver. Neurology 2004; 62:1408.
  39. Teepker M, Hamer HM, Knake S, et al. Myoclonic encephalopathy caused by chronic bismuth abuse. Epileptic Disord 2002; 4:229.
  40. Reif A, Leonhard C, Mössner R, et al. Encephalopathy and myoclonus triggered by valproic acid. Prog Neuropsychopharmacol Biol Psychiatry 2004; 28:1061.
  41. Evidente VG, Caviness JN. Focal cortical transient preceding myoclonus during lithium and tricyclic antidepressant therapy. Neurology 1999; 52:211.
  42. Caviness JN, Evidente VG. Cortical myoclonus during lithium exposure. Arch Neurol 2003; 60:401.
  43. Gupta HV, Caviness JN. Post-hypoxic Myoclonus: Current Concepts, Neurophysiology, and Treatment. Tremor Other Hyperkinet Mov (N Y) 2016; 6:409.
  44. Frucht SJ. The clinical challenge of posthypoxic myoclonus. Adv Neurol 2002; 89:85.
  45. Chadwick D, Hallett M, Jenner P, Marsden CD. Treatment of posthypoxic action myoclonus: implications for the pathophysiology of the disorder. Adv Neurol 1986; 43:183.
  46. Kuzniecky R, Berkovic S, Andermann F, et al. Focal cortical myoclonus and rolandic cortical dysplasia: clarification by magnetic resonance imaging. Ann Neurol 1988; 23:317.
  47. Muraga K, Suda S, Nagayama H, et al. Limb-shaking TIA: Cortical myoclonus associated with ICA stenosis. Neurology 2016; 86:307.
  48. Brown P. Hyperekplexia. In: Handbook of Clinical Neurophysiology, Elsevier, Amsterdam 2003. p.479.
  49. Gregoire SM, Laloux P, Hanson P, et al. Segmental spinal myoclonus and syringomyelia: A case report. Acta Neurol Belg 2006; 106:37.
  50. Brown P, Thompson PD, Rothwell JC, et al. Axial myoclonus of propriospinal origin. Brain 1991; 114 ( Pt 1A):197.
  51. Facini C, Barsacchi M, Piccolo B, et al. Early onset of propriospinal-like myoclonus in a child following a vertebral fracture. Neurology 2016; 87:956.
  52. Roze E, Bounolleau P, Ducreux D, et al. Propriospinal myoclonus revisited: Clinical, neurophysiologic, and neuroradiologic findings. Neurology 2009; 72:1301.
  53. Deuschl G, Mischke G, Schenck E, et al. Symptomatic and essential rhythmic palatal myoclonus. Brain 1990; 113 ( Pt 6):1645.
  54. Deuschl G, Toro C, Valls-Solé J, et al. Symptomatic and essential palatal tremor. 1. Clinical, physiological and MRI analysis. Brain 1994; 117 ( Pt 4):775.
  55. Wakata N, Sugimoto H, Iguchi H, et al. A case of voluntary palatal myoclonus with ear click: relationship between palatal myoclonus and click. Eur Neurol 2002; 48:52.
  56. Fabiani G, Teive HA, Sá D, et al. Palatal myoclonus: report of two cases. Arq Neuropsiquiatr 2000; 58:901.
  57. Kutukcu Y, Imirzalioglu N, Odabasi Z, et al. Essential palatal myoclonus in monozygotic male twins. J Neurol 2003; 250:885.
  58. Bento RF, Sanchez TG, Miniti A, Tedesco-Marchesi AJ. Continuous, high-frequency objective tinnitus caused by middle ear myoclonus. Ear Nose Throat J 1998; 77:814.
  59. Golz A, Fradis M, Netzer A, et al. Bilateral tinnitus due to middle-ear myoclonus. Int Tinnitus J 2003; 9:52.
  60. Golz A, Fradis M, Martzu D, et al. Stapedius muscle myoclonus. Ann Otol Rhinol Laryngol 2003; 112:522.
  61. Oliveira CA, Negreiros Júnior J, Cavalcante IC, et al. Palatal and middle-ear myoclonus: a cause for objective tinnitus. Int Tinnitus J 2003; 9:37.
  62. Camerota F, Celletti C, Paoloni M, et al. Myoclonus of the scapula after acute long thoracic nerve lesion: a case report. Mov Disord 2006; 21:71.
  63. Brown P. Action myoclonus-renal failure syndrome: the definitive clinico-pathological description. Brain 2004; 127:2151.
  64. Roubergue A, Apartis E, Vidailhet M, et al. Myoclonus and generalized digestive dysmotility in triple A syndrome with AAAS gene mutation. Mov Disord 2004; 19:344.
  65. Sachdev P. Schizophrenia-like illness in velo-cardio-facial syndrome: a genetic subsyndrome of schizophrenia? J Psychosom Res 2002; 53:721.
  66. Jarvi O, Hakola P, Sourander P, et al. Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLO-SL). In: Population Structure and Genetic Disorders, Eriksson A, Forsius H, Nevanlinna H, Workman P, Norio R (Eds), Academic Press, New York 1980. p.656.
  67. Monday K, Jankovic J. Psychogenic myoclonus. Neurology 1993; 43:349.