Dystonia
◦ Dystonia is a disorder of movement characterized by sustained muscle contractions,
frequently causing twisting and repetitive movements and/or abnormal postures
◦ Dystonic movements are typically patterned and twisting, and may be tremulous
◦ Dystonia is often initiated or worsened by voluntary action and associated with
over ow muscle activation
◦ Sensory trick or geste antagoniste is speci c to dystonia - Eg: Allievation of dystonia
by touch
Classi cation
Clinical
Characteristics
Age of Onset Infancy: Birth to 2 years - Eg : GA1, IEM
Childhood : 3 to 12 years - Eg: Wilson disease
Adolescence : 13 to 20 years - Eg: Wilson disease
Early adulthood : 21 to 40 years
Late adulthood : >40 years
Body
Focal: Involving a single body region
distribution
Segmental : Involving two or more contiguous body regions
Multifocal : Involving two non contiguous or more (non contiguous or not) body
regions
Generalized ; Involving the trunk and at least two other sites
Hemidystonia : Involving more regions restricted to one body side
Temporal pattern Disease Course:
Static - Eg: Kernicterus
Progressive - Eg: PKAN
Variability :
Persistent: Dystonia that persists to approximately the same extent throughout
the day
Action-speci c: Dystonia that occurs only during a particular activity or task -
Eg: Writer’s Cramp
Diurnal: Dystonia uctuates during the day, with recognizable circadian
variations in occurence, severity and phenomenology Eg: Segawa Syndrome
(DOPA responsive dystonia)
Paroxysmal: Sudden self limited episodes of dystonia usually induced by a
trigger with return to pre existing neurologic state Eg: PKD, PNKD,PED
Associated
Isolated or combined with another movement disorder
features
Isolated : Dystonia is the only motor feature with the exception of tremor
Combined: Dystonia is combined with other movement disorders (such as
myoclonus, parkinsonism, etc)
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Etiology
Nervous system pathology Evidence of degeneration (progressive
structural abnormality, such as neuronal loss)
Evidence of structural (often static) lesions No
evidence of degeneration or structural lesion
Inherited or acquired Inherited (dystonia forms of proven genetic
origin)
AD/AR/XLR/Mitochondrial
Acquired (dystonia due to a known speci c
cause):
Cerebrovascular (infarction or hemorrhage) -
Moa Moa
Perinatal brain injury
Traumatic brain injury
infection - JE, West nile
Drug - Metoclopromide, Anti psychotics
Toxic - CO, Metal , Manganese poisoning
Neoplastic
Psychogenic
Idiopathic (unknown) Sporadic
Familial
MRI Patterns in dystonia
Two patterns of involvement
1. Globus pallidus
2. Straital (Caudate+putamen)
Globus Pallidus involvement
1. Kernicterus
2. Methyl malonic acidemia (MMA)
3. isovaleric acidemia (IA)
4. Pyruvate Dehydrogenase De ciency (PDH)
5. Pantothenate Kinase Associated Neurodegeneration (PKAN)
Striatal involvement
1. Acquired
• Infections : Mycoplasma, HHV-6, Streptococcus, Measles, Rotavirus, HSV-1
• Extrapontine myelinosis
• Demyelination
2. Inherited
• Mitochondrial : Leigh
• Organic acidurias: PA
• BTBGD - Give high dose Biotin and thiamine even if striatal involvement
• Wilson disease
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Treatment
1. An initial trial of carbidopa-Levodopa is indicated to identify those with DRD (Lin et al)
2. Striatal necrosis in MRI : Trial of biotin and thiamine
3. Symptomatic treatment: Trihexyphenidyl, benzodiazepines, baclofen, gabapentin
4. Surgical: Intrathecal baclofen, DBS
Monitoring:
Different scales used for monitoring of dystonia
1. DSAP: Dystonia severity action plan
2. UDRS: Uni ed Dystonia Rating Scale
3. BADS: Barry Albright Dystonia Scale
4. BFMDRS: Burke Fahn Marsden Dystonia Rating Scale
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