Dystonia
-Definition: Sustained or intermittent repetitious/stereotyped muscle contractions causing
twisting/abnormal postures.
-Involve both agonist and antagonist muscles.
-Speed can be fast or slow; adult onset is usually insidious onset.
-Action often makes it worse, or elicits it.
-Can vary with body position.
-Can have dystonic tremor at times, that can mimic ET.
-Worsened by stress and fatigue.
-Reduced by relaxation, hypnosis, sleep, SENSORY TRICKS.
-Can sometimes remit for weeks or months at a time (usually in first 3 years of onset).
-Usually not painful or fixed until late in the disease, when contractures form (exception is cervical
dystonia, usually painful).
-VAST majority of focal dystonias are idiopathic.
PATHOPHYSIOLOGY:
-Loss of inhibition of movement system
-Increased plasticity of neural connections
CLASSIFICATION:
Describe by age of onset, distribution, temporal pattern, other abnormalities, and etiology (2013
classification system)
1) Age:
-Infancy (birth to 2 years): usually metabolic
-Age 3-20: usually combined/generalized, usually inherited
-Age 21 and older: Usually focal or segmental, and idiopathic.
2) Distribution:
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Focal – localized to a specific body part (most common)
Segmental – involves 2 or more adjacent body parts (second most common)
Multifocal – involves 2 or more non-adjacent body parts
Hemidystonia (Unilateral) – involves arm and leg on only one side
Generalized – Trunk plus two other regions
-Primary dystonia begins with focal dystonia, can then spread to be segmental or generalized
-Even in a family, some can have focal, while others have segmental or generalized types.
-Same meds can help the different types of dystonia
3) Temporal pattern:
-Persistent
-Action-induced
-Diurnal
-Paroxysmal
4) Other abnormal movements also occurring
-If not, call it primary dystonia
5) Other systemic features or other neurologic abnormalities
-If not, call it primary dystonia
6) Etiology based on neuropathology
-Structural lesion
-No structural lesion
-degenerative
7) Etiology based on inheritance vs. acquired
-Inherited (AR, AD, X-linked, mitochondrial)
-Acquired
-Idiopathic
CAUSES OF DYSTONIA:
1) Genetic
See: http://www.cmdg.org/Dystonia/Dystonia_genetics/dystonia_genetics.htm
A) Some isolated genetic dystonias:
-DYT1: AD but 30-40% penetrance (1/3 with gene will show symptoms); early onset (mainly <
age 26), generalized. Limbs involved first, then spreads. Younger age + leg as site of onset= more
likely it will spread. TOR1A gene. Ashkenazi Jews.
-DYT4: AD, generalized
-DYT6: AD, generalized, early onset but can occur up to age 49. Usually starts arm or cranial,
usually remains upper body. Speech is usually affected.
B) Some “Dystonia Plus” genetic syndromes:
-DYT5 (dopa-responsive dystonia): AD or AR: Childhood onset usually (<age 16); starts in
legs with toe walking, 50% are specifically worse at night, parkinsonism, markedly improved with lowdose dopamine (50-200mg per day), no pathologic neurodegeneration; normal PET/SPECT. Adult
onset more neck focal dystonia. Not get dyskinesia/wearing off.
-DYT12: (rapid-onset dystonia parkinsonism). AD. Adolesence to adult onset. Evolves to
generalized dystonia in hours to weeks. Parkinsonism. No response to levodopa. Pathology normal.
Plateaus. Quite rare.
-DYT 11 (Myoclonus Dystonia): AD, variable penetrance. Variable age of onset, usually young.
Usually involves upper body, legs spared. Slowly progressive, plateaus. Responds to alcohol.
2) Idiopathic
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Blepharospasm (trick: speak or remain silent, look down, touch corner of eye;
worse with blinking or bright lights, looking up, reading; mean age 60)
Cervical Dystonia (torticollis, antero/retrocollis, laterocollis etc; frequently painful;
mean age 40)
Meige syndrome (cranial facial dystonia)
Occupational/Task specific dystonia (ie, writer's cramp)
Focal limb dystonia (usually task-specific; lower extremity dystonia in kids usually
generalizes; in adult leg dystonia may suggest structural lesion or PD; lower
extremity dystonia can be improved when walking backwards)
Spasmotic dysphonia (vocal cords; adductor vs. abductor; mean age 30-50)
Oromandibular dystonia: (trick: toothpick in mouth, bite on hard object, touch
bottom of jaw; mean age 60).
Task specific: Writers cramp (trick: hold pen in novel way), Musician cramp,
golfer cramp, etc
3) Secondary
Tumor, stroke, MS, trauma, or other mass or structural lesion
Tardive dystonia 2/2 meds
Neurodegenerative disease (Parkinson's, MSA, PSP, CBD, Huntington's, Wilsons,
neuroacanthocytosis)
Encephalitis
Paraneoplastic
Anti-phospholipid antibody
4) Fixed (posture) dystonia:
Most are psychogenic. Non-changing with change in body posture, can’t be altered by examiner.
Need to examine under sleep (if absent in sleep, usually psychogenic); CAN still cause contractures.
5) DDx: Structural (MSK, masses, skeletal deformities, etc)
Workup
-Characterize the dystonia as above, do a good neuro/movement disorders history and exam, and
then try to establish if genetic vs. isolated focal dystonia vs. dystonia + other
features/generalized/weird
A) Genetic: What mode of inheritance based on history? See what genetic dystonia syndrome this
would be consistent with. Get MRI brain. Consider genetic testing (AFTER genetic counseling) if
clear family history or clear DYT syndrome.
B) Isolated focal dystonias: Get MRI brain and (if onset < age 40) Wilson’s labs; otherwise no further
workup.
C) Dystonia + other features/generalized/weird: Get MRI brain. Consider ancillary testing (for Wilsons,
paraneoplastic, etc). Check medication list for offending agents.
Treatment:
1) General points:
-Identify treatable cause (Wilson’s, drugs, structural lesions, metabolic abnormalities)
-If no treatable cause, treatment is symptomatic.
-Education/genetic counseling
-Address comorbidities (depression, etc)
-Explain treatment is symptomatic, not curative or protective.
-Select treatment according to severity, age, type, and distribution
-Encourage patients to discover sensory tricks.
-Range of motion exercises to present contractures. DO NOT use immobilization techniques.
-L-dopa in young dystonia
-Surgery as last resort.
2) PHYSICAL, SUPPORTIVE, AND ANCILLARY:
-PT (prevent contractures, range of motion exercises) and OT (adaptive devices for sensory tricks,
etc)
3) DRUGS/SURGERY:
A) GENERALIZED DYSTONIA
0.5) **Always try Levodopa (Sinemet) trial to rule out dopa-responsive dystonia if
younger-onset or parkinsonism.
1) Anticholinergics:First line for generalized dystonia. Artane (trihexyphenidyl) start 1mg
BID, increasing SLOWLY over MONTHS up to as much as 80-140mg/day over LONG time.
DO NOT stop suddenly, requires slow taper. Side effects include dry mouth, urinary retention,
constipation, memory loss, confusion, blurry vision, worsening of glaucoma; can treat these
symptomatically.
2) Tetrabenazine (dopamine depleting);12.5 mg daily, increase to 50-75mg daily.
3) Muscle relaxants (benzos, flexiril, baclofen/pump)
4) Anticonvulsants (carbamezapine, pregabalin, leviteracitam, zonisamide)
5) Deep brain stimulation: Best for medically refractory genetic or idiopathic generalized or
segmental dystonias (ie, DYT1). NOT a cure. Predictors of success are primary dystonia,
younger age of onset, short disease duration, and less severity. Currently GPi is the preferred
location (more studied), but STN may have less bradykinesia.
B) FOCAL DYSTONIA
-Botox, Botox, Botox (first line for focal or segmental dystonias)  light chain cuts proteins
at presynapse, keeps Ach from being released from presynapse (See “Evidence based review
and assessment of botulinum neurotoxin for the treatment of movement disorders” by Hallett et
al. for specific toxin for each condition).
ADDITIONAL NOTE ON STATUS DYSTONICUS: severe generalized stiffness, fever, markedly
elevated CK, respiratory, renal problems. Versed gtt  add propafol  pentobarb coma  baclofen
infusion  surgery, DBS