Approach

Treatment strategies for dystonias are highly dependent upon the age of onset and the affected body region.

For all patients, regular physiotherapy, bracing, and stretching are recommended to alleviate pain and prevent contractures.[37]​ Patients with acquired dystonia (e.g., Wilson's disease, Parkinson's disease) and a treatable underlying cause should receive appropriate disease-specific treatment.

Acute dystonic reactions

Acute onset of dystonia is rare and, in most cases, is due to exposure to antidopaminergic agents. Initial evaluation in the emergency setting should include assessment of the airway.[45] If exposure to antidopaminergic agents is confirmed, give intravenous diphenhydramine or benzatropine and repeat if no effect is seen. Some patients with poorly controlled generalised dystonia may develop acute worsening of their dystonia which can be severe and life-threatening. If you suspect overlapping neuroleptic malignant syndrome, malignant hyperthermia, serotonin syndrome, or other acute infectious, metabolic, or toxic derangement as a cause for the acute worsening, treatment should be directed at these underlying aetiologies. See Neuroleptic malignant syndrome (Management approach); Malignant hyperthermia (Management approach); Serotonin syndrome (Management approach).

Generalised dystonias

It is important to establish whether patients with generalised dystonia are responsive to dopaminergic therapy. A therapeutic trial of levodopa with a decarboxylase inhibitor (carbidopa) should be given, which will determine whether the patient has dopa-responsive dystonia (DRD).[37]​ Responsiveness should be apparent within a few days to weeks.[39][46] DRD typically presents in childhood (DRD may comprise 5% to 10% of childhood-onset dystonia), but adults may also respond to treatment.[3] Some patients with other forms of dystonia may still respond to levodopa but usually less so and require higher doses than patients with DRD.

In a minority of patients, levodopa exacerbates dystonia.

If the dystonia does not improve with levodopa given for at least 4 weeks, the mainstay of oral symptomatic therapy consists of anticholinergic therapy. Trihexyphenidyl was shown in a double-blind, randomised, placebo-controlled study to produce a 50% improvement in dystonia ratings.[47]​ Anticholinergics in general are thought to be more effective in children than in adults, although this may be the result of higher doses being tolerated more easily by children.[48]

Antispasmodic medications may be given with levodopa or trihexyphenidyl. Oral baclofen has demonstrated efficacy in improving gait in some patients with TOR1A (also known as DYT1) mutations, although no randomised controlled trials investigating its use exist.[49] Clonazepam or zonisamide may also be helpful, particularly for myoclonic dystonia.[48][50]​​ Intrathecal baclofen has been proposed for use in cases of secondary dystonia when accompanied by spasticity, and may also be considered in children when dystonia is accompanied by cerebral palsy.[51][52]

​Although trihexyphenidyl, levodopa, and pallidal deep brain stimulation have been explored for dystonia related to cerebral palsy, there is little evidence supportive of overall benefit.[53][54]

Focal dystonias

Most focal dystonias in adults and children do not respond to oral medications such as trihexyphenidyl and levodopa so botulinum toxin is usually the first line treatment.[39]

A number of randomised, placebo-controlled trials for various movement disorders have demonstrated efficacy of botulinum toxin in reducing the severity of the dystonia as well as pain and disability, and in improving quality of life measures.[55][56]​​ The best evidence exists for cervical dystonia.[57][58][59][60]​​​​​ [ Cochrane Clinical Answers logo ] ​ One Cochrane review found a significant and clinically relevant reduction in cervical dystonia-specific impairment and pain following a single treatment session of botulinum toxin type A.[60]

​Botulinum toxin is available in two serotypes: type A and type B. Doses depend on the size of the muscle being injected and the serotype used.[61]​ Referral to a neurologist experienced in movement disorders and injection of botulinum toxin is strongly recommended when considering this treatment for cervical dystonia, blepharospasm, spasmodic dysphonia, writer's cramp, or focal lower limb dystonia.

Transcutaneous electrical nerve stimulation (TENS) has shown to be helpful for writer's cramp and speech therapy may be helpful as an adjunct to botulinum toxin for laryngeal dystonia.[62]

A trial of levodopa instead of botulinum toxin may be given for adults with isolated foot dystonia, especially if subtle signs of parkinsonism are present. Trihexyphenidyl (to a maximum tolerated dose) is a secondary option for isolated foot dystonia.

Treatment-refractory generalised, segmental, and focal dystonias

Deep brain stimulation (DBS) of the internal globus pallidus may be used in cases where oral medications or botulinum toxin have failed to improve dystonia.

DBS is approved by the US Food and Drug Administration under a humanitarian device exemption for treatment of primary generalised, segmental, cervical dystonia, or hemidystonia. DBS is thought to restore abnormal firing rates and patterns in the main outflow nucleus from the basal ganglia to the motor cortex. One Cochrane review found that DBS may improve functional capacity and reduce symptom severity in adults with cervical, segmental, or generalised moderate to severe dystonia, and may improve quality of life in adults with generalised or segmental dystonia, although the evidence was of low quality.[63]​ Subthalamic nucleus DBS has shown some benefit in patients with toe dystonia related to Parkinson’s disease.[64]

​The following factors may have an affect on the success rate of DBS: the duration of dystonia before DBS, TOR1A (also known as DYT1) mutation status, the severity of disease, and whether the dystonia is idiopathic or acquired.[65][66]​ Although data are equivocal, there are several case series indicating that idiopathic dystonias may be more likely than acquired dystonia to respond to a clinically meaningful degree, with the exception of tardive dystonias, which appear to respond very well to DBS of the internal globus pallidus.[67][68]​ Consensus guidelines for patient selection suggest that there is currently not enough evidence to include or exclude candidates based on age, disease duration, or previous ablative procedures.[69]

Referral to a neurosurgery centre experienced in DBS implantation in dystonia is strongly recommended, especially in the case of children, for whom early referral may be a factor in a successful outcome.[70]

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