dystonia

Last edited 04/2022 and last reviewed 05/2022

Dystonia is a movement disorder characterized by sustained muscle contractions, repetitive twisting movements, and abnormal posturing of the trunk, neck, face, or arms and legs (1)

There is impairment of muscle tone resulting in an abnormal posture with excessive contraction of antagonist muscles. A limb is usually held in an extreme of flexion or extension. Facial muscles and the tongue may be involved.

• most common forms of dystonia in adults are focal, affecting the neck (cervical dystonia), eyes (blepharospasm), or associated with a task (eg, writer's cramp)
• dystonia can also present with a generalised pattern, which is more common with childhood onset forms

It is often a very isolated, focal condition - for example the hand in writer's cramp. Alternatively, it may be more generalised, as occurs in idiopathic torsion dystonia, or segmental. Dystonia may be a complication of neuroleptic use.

Dystonia is a movement disorder

• characterised by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both
• dystonic movements are typically patterned, twisting, and may be tremulous
• dystonia is often initiated or worsened by voluntary action and associated with overflow muscle activation

Dystonia can be treated conservatively or surgically:

• currently available conservative management options for dystonia improve the symptoms but do not cure the underlying neurological disorder. The severity of dystonia may progress over time as part of the underlying neurological condition
• surgical options include thalamotomy and pallidotomy; however, benefits may not be maintained in the long term (2)
• deep brain stimulation is another treatment option
  • the safety and efficacy of deep brain stimulation for tremor and dystonia (excluding Parkinson's disease) appears adequate to support the use of this procedure (2)

Key messages (3):

• dystonia is a neurological condition characterised by abnormal postures and movements resulting from abnormal neural control of muscles

• most common forms of isolated dystonia in adults are focal, affecting the neck (cervical dystonia), eyes (blepharospasm), or associated with a task (eg, writer's cramp)

• acute and tardive dystonia can occur as complications of medications such as dopamine receptor blockers

• neurophysiotherapy, botulinum toxin injections, and deep brain stimulation are effective treatments

• management of non-motor symptoms such as depression, anxiety, and associated pain are also important

Note:

Dystonia is often confused with spasticity or rigidity and sometimes mistakenly attributed to psychogenic causes. Sometimes the diagnosis is missed and patients often consult several physicians before the correct diagnosis is made (1)

Reference:

1. Tarsy D and Simon DK, Dystonia, N Engl J Med 2006 ; 355:818, Review Article
2. NICE (August 2006).Deep brain stimulation for tremor and dystonia (excluding Parkinson's disease).
3. Sadnicka A, Meppelink A, Kalinowski A, Oakeshott P, van den Dool J. Dystonia BMJ 2022; 377 :e062659 doi:10.1136/bmj-2020-062659