Overview
Dystonia
1. Topic Overview (Clinical Overview)
Summary
Dystonia is a movement disorder characterised by sustained or intermittent muscle contractions causing abnormal, often repetitive movements and/or postures. It can be focal (Affecting one body region – Most common: Cervical Dystonia), segmental (Two+ adjacent regions), multifocal, hemidystonia, or generalised. The most common form in adults is Cervical Dystonia (Spasmodic Torticollis) – involuntary twisting/tilting of the neck. A characteristic clinical sign is the "Sensory Trick" (Geste Antagoniste) – Touching the affected area (e.g., touching the chin in cervical dystonia) temporarily relieves the abnormal posture. Treatment of choice for focal dystonia is Botulinum Toxin (Botox) injections. Acute Dystonic Reactions (Drug-induced, e.g., from Metoclopramide) are a medical emergency requiring Procyclidine/Benztropine IV/IM. Investigation is needed to exclude secondary causes, particularly Wilson's Disease (Treatable).
Key Facts
- Definition: Sustained/Intermittent muscle contractions -> Abnormal movements/postures.
- Classification by Distribution: Focal, Segmental, Multifocal, Hemidystonia, Generalised.
- Most Common Adult Dystonia: Cervical Dystonia (Spasmodic Torticollis).
- Sensory Trick (Geste Antagoniste): Touching the affected area transiently improves dystonia.
- Treatment (Focal): Botulinum Toxin injections.
- Acute Dystonic Reaction: Drug-induced (Metoclopramide, Antipsychotics). Treat with Anticholinergics (Procyclidine IV).
Clinical Pearls
"The Geste Antagoniste": A patient who touches their chin to relieve a head tilt has Cervical Dystonia.
"Oculogyric Crisis = Procyclidine": Forced upward eye deviation from dopamine blockers (Metoclopramide). Stat anticholinergic.
"Wilson's in Young Dystonia": Always check serum Caeruloplasmin and 24-hr urinary copper in young-onset dystonia.
"Botox Every 3 Months": Focal dystonia responds well to repeated Botulinum Toxin injections.
Why This Matters Clinically
Dystonia can be debilitating. Focal forms are very treatable with Botulinum Toxin. Recognising acute drug-induced dystonia and treating promptly prevents distress and serious complications.
2. Epidemiology
Incidence
- Prevalence: ~16-30 per 100,000 (All dystonias). Focal dystonia more common.
- Age: Focal (Adult-onset, typically >40). Generalised (Often childhood-onset).
- Sex: Cervical Dystonia – Female predominance.
3. Classification
By Distribution (Body Region)
| Type | Definition | Examples |
|---|---|---|
| Focal | One body region. | Cervical Dystonia, Blepharospasm, Writer's Cramp. |
| Segmental | Two or more adjacent regions. | Cranial-Cervical (Meige Syndrome + Cervical). |
| Multifocal | Two or more non-adjacent regions. | Arm + Leg dystonia. |
| Hemidystonia | One side of the body. | Suggests structural lesion (Stroke, Tumour). |
| Generalised | Trunk + 2 other regions. | Primary Generalised Dystonia (DYT1). |
By Aetiology
| Type | Examples |
|---|---|
| Primary (Idiopathic) | No identifiable cause. Most focal dystonias. DYT1 (Generalised). |
| Secondary (Acquired) | Drug-induced, Cerebral palsy, Stroke, Head trauma, Wilson's Disease, Huntington's. |
| Heredodegenerative | Part of a degenerative disease (e.g., Parkinson's, Huntington's). |
By Age of Onset
| Age | Typical Pattern |
|---|---|
| Childhood (<12) | Often generalised. May be genetic (DYT1). Check for Wilson's. |
| Adolescence | May progress from focal to generalised. |
| Adult (>6) | Usually focal. Rarely generalises. |
4. Common Focal Dystonias
Cervical Dystonia (Spasmodic Torticollis)
| Feature | Detail |
|---|---|
| Most Common Adult Focal Dystonia | |
| Presentation | Involuntary twisting/tilting of the neck. Tremor ("Yes-Yes" or "No-No"). Pain is common. |
| Postures | Torticollis (Rotation), Laterocollis (Side tilt), Retrocollis (Extension), Anterocollis (Flexion). |
| Geste Antagoniste | Touching chin, Face, Occiput temporarily relieves. |
| Treatment | Botulinum Toxin. |
Blepharospasm
| Feature | Detail |
|---|---|
| Definition | Involuntary, forceful, bilateral eyelid closure. |
| Presentation | Increased blinking -> Sustained eye closure. Functionally blind. |
| Triggers | Bright light, Stress. |
| Geste Antagoniste | Touching eyebrow. |
| Treatment | Botulinum Toxin (Orbicularis Oculi). |
Writer's Cramp (Task-Specific Dystonia)
| Feature | Detail |
|---|---|
| Definition | Dystonic posturing of hand/arm during writing. |
| Presentation | Abnormal grip, Wrist posturing. Only present during the specific task. |
| Variants | Musician's Dystonia ("Focal Hand Dystonia of Musicians"). |
| Treatment | Botulinum Toxin (Less Consistently Effective). Retraining. |
Oromandibular Dystonia
| Feature | Detail |
|---|---|
| Definition | Dystonia of jaw, Tongue, Lower face. |
| Presentation | Jaw opening, Jaw closing, Grinding, Tongue protrusion. Speech/Eating difficulties. |
| Meige Syndrome | Blepharospasm + Oromandibular Dystonia. |
Laryngeal Dystonia (Spasmodic Dysphonia)
| Feature | Detail |
|---|---|
| Definition | Dystonia of vocal cords. |
| Presentation | Strained, Strangled voice (Adductor type). Breathy, Whispery voice (Abductor type). |
| Treatment | Botulinum Toxin to vocal cord muscles (ENT). |
5. Acute Dystonic Reaction (Drug-Induced)
Causes
| Drug Class | Examples |
|---|---|
| Dopamine Receptor Blockers | Antipsychotics (Haloperidol, Risperidone). Antiemetics (Metoclopramide, Prochlorperazine). |
Clinical Features
| Feature | Notes |
|---|---|
| Onset | Acute. Usually within hours to days of drug exposure. |
| Oculogyric Crisis | Forced, Sustained upward deviation of eyes. |
| Torticollis | Neck twisting. |
| Trismus | Jaw spasm. |
| Opisthotonus | Arching of back. |
| Laryngeal Dystonia | Rare but dangerous (Stridor, Airway compromise). |
Management (Emergency)
| Drug | Dose | Route | Notes |
|---|---|---|---|
| Procyclidine | 5-10mg | IV/IM | Anticholinergic. Rapid effect IV. |
| Benztropine | 1-2mg | IV/IM | Alternative. |
Relief within minutes of IV anticholinergic.
Continue oral anticholinergic for 24-48 hours (Prevent recurrence).
6. Pathophysiology
Mechanism
- Dysfunction of Basal Ganglia circuitry.
- Reduced Inhibition from Sensorimotor circuits.
- Abnormal plasticity.
- Abnormal co-contraction of agonist and antagonist muscles.
Genetics (Selected)
| Gene | Syndrome | Inheritance |
|---|---|---|
| DYT1 (TOR1A) | Primary Generalised Dystonia (Oppenheim's). | Autosomal Dominant (Low penetrance). Ashkenazi Jewish. |
| DYT6 (THAP1) | Adolescent-Onset Dystonia. Cranio-Cervical predominance. | AD. |
| DYT5 (GCH1) | Dopa-Responsive Dystonia (Segawa's). Diurnal fluctuation. | AD. |
| DYT11 (SGCE) | Myoclonus-Dystonia. | AD. |
7. Investigations
Who to Investigate?
- Young Onset (<26).
- Atypical Features (e.g., Hemidystonia, Rapid progression, Pyramidal signs).
- Suspected Secondary Cause.
Investigations
| Test | Purpose |
|---|---|
| Serum Caeruloplasmin + 24hr Urinary Copper | Wilson's Disease (Low Caeruoloplasmin, High urinary copper). |
| Slit Lamp Examination | Kayser-Fleischer rings (Wilson's). |
| MRI Brain | Exclude structural lesions (Stroke, Tumour, Basal Ganglia abnormality). |
| Genetic Testing | DYT1.etc. |
| Trial of Levodopa | Dopa-Responsive Dystonia (Segawa's). Dramatic response. |
8. Management
Principles
- Exclude Secondary/Treatable Causes (Wilson's, Drug-induced).
- Botulinum Toxin for Focal Dystonia.
- Oral Medications for Generalised / Multifocal.
- Deep Brain Stimulation (DBS) for Severe Refractory Cases.
- Physiotherapy / Occupational Therapy.
Botulinum Toxin (Botox / Dysport / Xeomin)
| Feature | Detail |
|---|---|
| Mechanism | Blocks Acetylcholine release at neuromuscular junction. Weakens overactive muscles. |
| Indication | First-line for Focal Dystonia (Cervical, Blepharospasm, Writer's Cramp). |
| Administration | IM injections into affected muscles. Often EMG-guided. |
| Duration | ~3 months. Repeat injections needed. |
| Side Effects | Local weakness. Dysphagia (Cervical). Ptosis (Blepharospasm). Antibody development (Rare). |
Oral Medications
| Drug | Mechanism | Notes |
|---|---|---|
| Anticholinergics (Trihexyphenidyl) | Central anticholinergic. | Useful in generalised dystonia. Limited by side effects (Dry mouth, Confusion, Urinary retention). |
| Baclofen | GABAb agonist. | May help. |
| Levodopa | Dopamine precursor. | Specific for Dopa-Responsive Dystonia (Segawa's). |
| Benzodiazepines (Clonazepam) | GABAa agonist. | Adjunct. |
| Tetrabenazine | VMAT2 inhibitor (Depletes dopamine). | May help. Limited by depression/parkinsonism. |
Deep Brain Stimulation (DBS)
| Feature | Detail |
|---|---|
| Target | Globus Pallidus Internus (GPi). |
| Indication | Severe, Medically refractory dystonia (Generalised, Segmental, Cervical). |
| Efficacy | Can be very effective. Best in Primary Generalised (DYT1). |
9. Complications
| Complication | Notes |
|---|---|
| Pain | Especially Cervical Dystonia. |
| Functional Disability | Writing, Walking, Vision. |
| Social Isolation / Depression | |
| Dysphagia / Aspiration | Oropharyngeal dystonia. Cervical Dystonia (Post-Botox). |
| Contractures | Fixed deformity (Late stage). |
10. Prognosis & Outcomes
| Type | Prognosis |
|---|---|
| Focal Dystonia (Adult Onset) | Rarely generalises. Good symptom control with Botox. Chronic. |
| Childhood Generalised | Progressive. DBS can be effective. |
| DYT1 | Variable. DBS response often good. |
| Drug-Induced Acute | Excellent if treated promptly. |
11. Evidence & Guidelines
Key Guidelines
| Guideline | Organisation | Notes |
|---|---|---|
| NICE | NICE | Guidance on Botulinum Toxin use. DBS pathways. |
| ABN / Movement Disorder Society | Professional Bodies | Clinical practice guidelines. |
| Dystonia Society UK | Charity | Patient information. |
12. Exam Scenarios
Scenario 1:
- Stem: A 45-year-old woman presents with involuntary turning of her head to the right, which she can temporarily relieve by touching her chin. What is the diagnosis and first-line treatment?
- Answer: Cervical Dystonia. Sensory Trick (Geste Antagoniste). First-line: Botulinum Toxin injections.
Scenario 2:
- Stem: A young patient presents with dystonia after receiving Metoclopramide for nausea. They have sustained upward eye deviation. What is the diagnosis and treatment?
- Answer: Acute Dystonic Reaction (Oculogyric Crisis). Treat with IV Procyclidine 5-10mg.
Scenario 3:
- Stem: What investigation should be performed in all young-onset dystonia to exclude a treatable cause?
- Answer: Serum Caeruloplasmin + 24-hour Urinary Copper (To exclude Wilson's Disease).
14. Triage: When to Refer
| Scenario | Urgency | Action |
|---|---|---|
| Suspected Focal Dystonia | Routine | Neurology / Movement Disorders. |
| Acute Dystonic Reaction | Emergency | IV Procyclidine/Benztropine. +/- A&E. |
| Young-Onset Dystonia (<26) | Urgent | Neurology. Investigate for Wilson's, Genetic causes. |
| Hemidystonia | Urgent | MRI Brain. Exclude structural lesion. |
15. Patient/Layperson Explanation
What is Dystonia?
Dystonia is a movement disorder where muscles contract abnormally, causing twisting movements or abnormal postures. It can affect different parts of the body.
What are the symptoms?
- Neck turning involuntarily (Torticollis).
- Eyes closing forcefully (Blepharospasm).
- Difficulty writing (Writer's Cramp).
How is it treated?
- Botox injections: Into the affected muscles. Works well for focal dystonia. Needs repeating every 3 months.
- Medications: Pills to relax muscles.
- Surgery (DBS): For severe cases.
Key Counselling Points
- Chronic Condition: "Dystonia is usually lifelong, but symptoms can be well controlled."
- Botox Works: "Injections are very effective and need to be repeated every 3 months."
- Support Available: "Organisations like the Dystonia Society can provide support."
16. Quality Markers: Audit Standards
| Standard | Target |
|---|---|
| Wilson's Disease excluded in young-onset dystonia | 100% |
| Botulinum Toxin offered for focal dystonia | >5% |
| Acute Dystonic Reaction treated promptly | 100% |
17. Historical Context
- Term "Dystonia": Coined by Oppenheim (1911) – "Dystonia Musculorum Deformans".
- Botulinum Toxin for Dystonia: First used 1980s. Revolutionised focal dystonia management.
- DBS for Dystonia: Approved and increasingly used since 2000s.
18. References
- Albanese A, et al. Phenomenology and classification of dystonia: a consensus update. Mov Disord. 2013. PMID: 23629998
- Dystonia Society UK: dystonia.org.uk
Last Reviewed: 2025-12-24 | MedVellum Editorial Team
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. If you have symptoms of dystonia, please consult a neurologist.