Dystonia

Original Editor - Muskan Rastogi Top Contributors - Muskan Rastogi and Neha Duhan
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Introduction/Definition[edit | edit source]

Dystonia is a hyperkinetic movement disorder in which involuntary contractions of muscles occur. It is characterised by sustained muscle contractions and abnormal trunk, neck, face, arms, and legs postures.[1]The term "Dystonia" was coined by Oppenheim in 1911 to express the problem of changing muscle tone and repetitive muscle spasms. Its original name was dystonia musculorum deformans which was later changed to torsion dystonia due changing understanding of the problem.

Dystonia is easily confused with other diagnoses such as spasticity and rigidity.[1]This condition can be present separately or in combination with chorea, myoclonus, tremor and parkinsonism.[2][3]

According to Movement Disorder Society, there are 3 more sub-definitions of Dystonia-

  • Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal and often repetitive, movements, postures, or both.
  • Dystonic movements are typically patterned, twisting, and may be tremulous.
  • Dystonia is often initiated or worsened by voluntary action and is associated with overflow muscle activation.[3]

Epidemiology[edit | edit source]

  • True prevalence of Dystonia still remains unclear due to the fact that this disorder encompasses a wide range of classification.[4] Although it's not rare to see dystonia in neurologically affected populations.
  • Patients with dystonia represent ~20% of patients in movement disorder clinics.[5][6][7]
  • Dystonia cases accounts for 15-30 cases per 100,000 in general population.[8][7][4]
  • In a study of a random sample of the population over 50 years of age, the prevalence of isolated dystonia was concluded to be 732 per 100 000, suggesting that in the ageing population dystonia is a common neurological disorder.[4][9]
  • Women are more likely to be affected with this condition than men with a ratio of 2:1.[4]
  • Adult-onset focal dystonia syndromes are by far the most frequent presentations of this disease. In recent researches on focal syndromes, the majority of patients had cervical dystonia (69%) or blepharospasm (17%) whilst other forms were much rarer: limb dystonia (3%–7%), spasmodic dysphonia (1%–3%), musician’s dystonia (3%) and oromandibular dystonia (1%).[4]

Quality of life[edit | edit source]

A lot of researches have investigated the health-related QOL in patients with dystonia and indicated a poorer QOL in these patients. Several causes affect QOL in patients, including impaired physical functioning owing to the presence of motor symptoms. The most severe, generalized forms of dystonia can affect all activities of daily living such as walking or hand function.

Focal forms of dystonia can also be disabling; for instance, laryngeal dystonia can affect communication, and blepharospasm can hinder safe driving or walking. Task-specific dystonia can obstruct professional occupations as in patients with writer’s cramp or musician’s dystonia. Cervical dystonia and dystonia-associated pain negatively affects employment status and productivity. The influence of neuropsychiatric comorbidities of dystonia on work life has not yet been systematically assessed.

Similarly, patients with dystonia often feel that the abnormal postures or associated dystonic tremors are socially disabling and disfiguring. Pain is the second most important predictor of QOL in patients with dystonia and is present in ~75% of patients with cervical dystonia but occurs less frequently in patients with other focal dystonias. Patients also report a poor quality of sleep, which correlates with depression but not with dystonia severity or muscle activity during sleep.[10]

Aetiology/Causes[edit | edit source]

  • Idiopathic Causes
  • Genetic Causes
  • Acquired Causes

Classification[edit | edit source]

Pathophysiology[edit | edit source]

Examination[edit | edit source]

Physical signs[edit | edit source]

There are 5 classical signs of Dystonia:-

  • 2 main physical signs- dystonic movements and dystonic posture.
  • 3 additional physical signs -mirror dystonia, overflow dystonia, and gestes antagonists/sensory tricks.
Physical Sign Descriptors
Dystonic Movements Muscle contractions may be continuous, forcing all limbs and trunk into sustained postures (not available for blepharospasm or laryngeal dystonia)

•Body part is flexed or twisted along its longitudinal axis.

• Slowness and clumsiness for skilled movements are associated with the sensation of rigidity and traction in the affected part.

Dystonic Posture These features have to be looked for in all movement disorders, either fast or slow, also when the immediate impression is that of a tremor, tic, chorea or myoclonus

• Tremor is a feature of dystonic movements and may appear as isolated tremor

• Movements are repetitive and patterned (i.e., consistent and predictable) or twisting

• Movements are often sustained at their peak to lessen gradually in a preferred posture (usually opposite to the direction of movement)

Gestes

antagonistes

(‘tricks’)

Voluntary actions performed by patients reduce or abolish abnormal posture or dystonic movements. They are usually simple movements involving, or directed to, the body region affected by dystonia

• These movements are natural and graceful, not consisting of forceful opposition to the phenomenology of dystonia

• The movement does not push or pull the affected body part but simply touches it (‘sensory trick’) or accompanies it during alleviation of dystonia

• Alleviation of dystonia occurs during the geste movement, usually soon after its start

Mirror

dystonia

It is evaluated in the upper or lower limbs. At least three different types of repetitive tasks (e.g., finger sequence, normal writing or piano-like movements) are performed at low and fast speed in the non-affected limb.

It is a unilateral posture or movement with the same or similar characteristics to the patient’s dystonia (usually postures and some movements) that can be elicited, usually in the more severely affected side when contralateral movements or actions are performed.

To be distinguished from non-dystonic mirror movements

Overflow

dystonia

It is observed at least once, usually ipsilaterally, in coincidence with the peak of dystonic movements

It is an unintentional muscle contraction accompanying the most prominent dystonic movement that is observed in an anatomically distinct neighbouring body region

Investigation, Screening and Prevention[edit | edit source]

  • EMG Mapping
  • MRI
  • Copper and Ceruloplasmin levels
  • Genetic Testing
  • CSF analysis (analysis of pterins, dopamine and serotonine metabolites and serum and/or CSF glucose ratio)
  • Lysosomal enzyme assays
  • Long-chain fatty acids
  • Urine metabolic screen (amino acids)
  • Skin or tissue biopsy

Diagnosis[edit | edit source]

Management[edit | edit source]

Botulinum toxin treatment[edit | edit source]

Transcranial magnetic stimulation[edit | edit source]

Deep Brain Stimulation[edit | edit source]

Physiotherapy Management[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 Tarsy D, Simon DK. Dystonia. New England Journal of Medicine. 2006 Aug 24;355(8):818-29.
  2. di Biase L, Di Santo A, Caminiti ML, Pecoraro PM, Di Lazzaro V. Classification of Dystonia. Life. 2022 Jan 29;12(2):206.
  3. 3.0 3.1 Albanese A, Bhatia K, Bressman SB, DeLong MR, Fahn S, Fung VS, Hallett M, Jankovic J, Jinnah HA, Klein C, Lang AE. Phenomenology and classification of dystonia: a consensus update. Movement disorders. 2013 Jun 15;28(7):863-73.
  4. 4.0 4.1 4.2 4.3 4.4 Albanese A, Di Giovanni M, Lalli S. Dystonia: diagnosis and management. European journal of neurology. 2019 Jan;26(1):5-17.
  5. Balint B, Mencacci NE, Valente EM, Pisani A, Rothwell J, Jankovic J, Vidailhet M, Bhatia KP. Dystonia. Nature reviews Disease primers. 2018 Sep 20;4(1):1-23.
  6. Jankovic J. Treatment of hyperkinetic movement disorders. The Lancet Neurology. 2009 Sep 1;8(9):844-56.
  7. 7.0 7.1 Steeves TD, Day L, Dykeman J, Jette N, Pringsheim T. The prevalence of primary dystonia: a systematic review and meta‐analysis. Movement Disorders. 2012 Dec;27(14):1789-96.
  8. Camfield L, Ben-Shlomo Y, Warner TT. Epidemiological study of Dystonia in Europe Collaborative Group impact of cervical dystonia on quality of life. Mov Disord. 2002;17(4):838-41.
  9. Müller J, Kiechl S, Wenning GK, Seppi K, Willeit J, Gasperi A, Wissel J, Gasser T, Poewe W. The prevalence of primary dystonia in the general community. Neurology. 2002 Sep 24;59(6):941-3.
  10. Balint B, Mencacci NE, Valente EM, Pisani A, Rothwell J, Jankovic J, Vidailhet M, Bhatia KP. Dystonia. Nature reviews Disease primers. 2018 Sep 20;4(1):1-23.