Cervical Dystonia
• 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
• Myoclonic or tremulous movements are
often superimposed in CD, producing a
“tremor like” appearance – especially early
in the disease state
• 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)
• M:F 1:1.2
• 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
• 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
• 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
• 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 70–80%
• 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
• Brain MRI is usually normal
• Cervical MRI may show cervical muscle
hypertrophy and cervical disc disease
• 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
• 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
• 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
• 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
• 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
• 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
• 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
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
• Botulinum toxin treatment results in the
improvement of neck posture, muscle
hypertrophy, and pain
• Effect of BoNT begins 3–12 days after an
injection and is sustained for
approximately 3 months
• 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
• 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?
• 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
• 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
• Lower dose is used initially in the newly
diagnosed CD patient
• 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