Cervical Dystonia

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Cervical Dystonia
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• Originally known as spasmodic torticollis and
  first described by Foltz in 1959, is a
  neurological syndrome characterized by abnormal
  head and neck posture due to tonic involuntary
  contractions in a set of cervical muscles

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• Myoclonic or tremulous movements are often
  superimposed in CD, producing a tremor like
  appearance especially early in the disease state

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• Classified into 4 types based on the principal
  direction of head posture
• 1.Torticollis (abnormal rotation of the head to
  the right or to the left in the transverse plane)
• 2.Laterocollis (the head tilts toward the right
  or left shoulder)
• 3.Anterocollis (the head pulls forward with neck
  flexion)
• 4.Retrocollis (the head pulls back with the neck
  hyperextended)

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• MF 11.2
• Onset is usually insidious, although in some
  patients the onset has been reported as sudden
• Cervical dystonia may develop in patients of all
  age groups, but the peak age of onset is 41 years

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• Idiopathic CD usually progresses in severity over
  the first five years until it reaches a plateau,
  during which time the CD remains fairly constant
  and becomes a lifelong condition
• Although remission can occur, it is rare and the
  dystonia usually returns after a period of time

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• Transient relief from symptoms with a sensory
  trick or geste antagoniste.
• A common form of a sensory trick in CD is placing
  the hand lightly on the cheek. This allows the
  head to return to a more normal posture
• Resting the head against the headrest while
  driving or against a pillow while watching TV are
  examples of sensory tricks

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• May obtain temporary relief from symptoms of CD
  in the morning hours following sleep
• Stress can exacerbate symptoms of CD
• Neck pain is common in CD and has been reported
  in 7080

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• Pain does not appear to be correlated with the
  degree of severity of CD, and is thought to
  involve central mechanisms in addition to pain
  arising from muscle spasms
• Degenerative disc disease seems to be accelerated
  in CD, which can aggravate the pain associated
  with this disorder
• Depression, anxiety, and social phobia are also
  common associated conditions

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• Brain MRI is usually normal
• Cervical MRI may show cervical muscle hypertrophy
  and cervical disc disease

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• Most often, the cause of CD is unknown
• Cases of hereditable forms of CD, such as DYT7,
  autosomal dominant transmission and incomplete
  penetrance
• Affected family members may present with
  different signs/symptoms in different body regions

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• A component of various secondary dystonias that
  manifest in a number of neurodegenerative
  diseases
• Secondary causes of CD include neuroleptic
  medication exposure or trauma
• May occur following a relatively mild trauma
• Usually begins within days of an incident, lacks
  the sensory trick response and tends to be more
  resistant to treatment with botulinum toxin

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• 54 muscles affecting action on head and neck
  posture
• Dystonic muscles can show a dominant tonic
  activity, myoclonic or tremulous activity often
  in complex mixtures

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• Intramuscular injections of BoNT are considered
  the first line of treatment in CD
• Both botulinum toxin serotype A (BoNT-A) (Botox,
  Dysport, Xeomin) and serotype B (BoNT-B)
  (NeuroBloc/Myobloc) have been used

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• Anticholinergic trihexyphenidyl and benztropine
  have some beneficial effects and can be used in
  more severe cases alongside BoNT injections
• Benzodiazepines, such as diazepam or lorazepam,
  and tricyclic antidepressants, such as
  amitriptyline and nortriptyline

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• Surgical treatment with selective peripheral
  denervation has been reported in open studies to
  be helpful in some severe cases that do not
  respond to either oral medications or
  chemodenervation

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• Surgical myectomy has also been used however,
  the dystonia tends to involve other muscles or
  continues to involve remnants of the resected
  muscles
• Deep brain stimulation

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BTX in Cervical Dystonia

• The most effective treatment for CD
• Treatment with BoNT should be initiated as early
  as possible, since secondary changes to the
  muscles involved (contractures) and of connective
  tissues, bony tissues, and cervical discs may
  occur with longstanding CD
• Worsening of CD while being treated with BoNT
  could be due to resistance of BoNT or the result
  of an actual increase in severity often, wrong
  muscles have been injected

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• Botulinum toxin treatment results in the
  improvement of neck posture, muscle hypertrophy,
  and pain
• Effect of BoNT begins 312 days after an
  injection and is sustained for approximately 3
  months

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• Injections at 3-month intervals (or longer) are
  thought to reduce the risk of antibodies to the
  BoNT
• number of injection sites within a muscle ranges
  from one site in smaller muscles to eight sites
  in larger muscles

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• The following questions must be answered before
  BoNT therapy of CD is considered
• 1. Is the abnormal posture of the head and of
  the shoulder induced by dystonia or by another
  abnormality that only imitates CD?
• 2. Is the CD the primary cause of disability?
• 3. Does the patient have myasthenia gravis or
  other neuromuscular junction disorders?
• 4. Are there already secondary changes of
  muscles or connective and bony tissues?

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• Patients must be requested to release any
  compensatory voluntary muscle activities in
  non-dystonic muscles, avoid the use of sensory
  tricks (geste antagoniste), and report accurately
  on pain severity
• They should be asked to perform slow head
  movements in all common directions evaluation of
  head posture is performed with the patient
  standing, walking slowly, and lying down

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• In cases of bilateral injections in the
  sternocleidomastoid, the dose per muscle is half
  of the regular dose Swallowing problems happen
  more frequently in cases of bilateral injections
  to the SCM
• In cases of bilateral injection into the splenius
  capitis and semispinalis capitis muscles, the
  individual dose per muscle should be reduced to
  60 of the regular dose to prevent neck weakness
  Neck muscle weakness, which may cause problems
  with holding the head upright, is more frequent
  if injecting splenius capitis and semispinalis
  capitis muscles bilaterally

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• Lower dose is used initially in the newly
  diagnosed CD patient

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• Side effects of BoNT include hypersensitivity
  reactions, injection site infections, injection
  site bleeding or bruising, dry mouth, dysphagia,
  upper respiratory infection, neck pain, and
  headache
• To reduce the risk of developing resistance, a
  3-month interval between injections is recommended