Dystonia is a movement disorder characterized by slow, involuntary, and often twisting movements involving large muscle groups, including the limbs, trunk, and neck. It may present as intermittent episodes or continuous, sometimes painful contractions. Dystonia can result in abnormal postures, occasionally leading to permanent contractures. Common forms include focal dystonia (affecting a single body region, e.g., spasmodic torticollis), segmental, or generalized dystonia. Etiologies include hereditary, idiopathic, extrapyramidal disorders, or drug-induced causes.

Pathophysiology

Dystonia arises from dysfunction of the basal ganglia and associated extrapyramidal motor pathways. Abnormal signaling in these circuits leads to excessive co-contraction of agonist and antagonist muscles. Secondary dystonia can result from:

• Neurodegenerative diseases (e.g., Parkinson’s disease, Huntington’s disease)

• Drug-induced changes (e.g., phenothiazines, metoclopramide)

• Metabolic disorders (e.g., Wilson’s disease)

• Structural lesions affecting basal ganglia or thalamus

The disorder is aggravated by voluntary movements, walking, or emotional stress and usually improves with sleep.

Signs and Symptoms

• Slow, involuntary twisting or writhing movements

• Intermittent or continuous muscular contractions

• Abnormal postures: foot inversion, leg hyperextension, arm pronation, trunk arching, neck rotation (spasmodic torticollis)

• Painful contractions in severe cases

• Associated features may include dysarthria, dysphagia, emotional lability, and in chronic cases, permanent contractures

Clinical Assessment

History

• Determine onset, duration, and triggers (e.g., emotional stress, walking)

• Family history of dystonia or movement disorders

• Drug history (especially antipsychotics, phenothiazines, metoclopramide)

• Associated neurological symptoms (tremor, rigidity, chorea, weakness)

• Impact on daily activities and sleep

• Presence of comorbidities (neurodegenerative disorders, metabolic conditions)

Physical Examination

• Observe gait and posture

• Assess voluntary motor function:

  • Gross motor: heel-to-knee-to-toe test

  • Fine motor: finger-to-thumb opposition

  • Coordination: finger-to-nose test

• Assess muscle tone, strength, and presence of abnormal contractions

• Differentiate from other movement disorders:

  • Chorea: rapid, jerky, unpredictable

  • Athetosis: slow, continuous, writhing (hands/extremities)

• Look for dystonic postures of neck, trunk, or limbs

• Neurological examination for additional deficits

Investigation

• Laboratory tests: serum ceruloplasmin, copper levels (Wilson’s disease), metabolic panel

• Neuroimaging: MRI or CT of brain to identify basal ganglia lesions or structural abnormalities

• Electromyography (EMG): characterizes abnormal muscle contractions

• Genetic testing for hereditary forms of dystonia (DYT1 mutation, etc.)

• Drug review to assess for drug-induced dystonia

Medical causes of dystonia

Differential Diagnosis

• Chorea (rapid, jerky movements)

• Athetosis (continuous, writhing movements)

• Spasticity due to cerebral palsy or stroke

• Tics (sudden, repetitive movements)

• Parkinsonism

• Myoclonus

Pediatric Considerations

• Onset usually occurs after children can walk, rarely before age 10

• Common pediatric causes:

  • Dystonia musculorum deformans

  • Fahr’s syndrome

  • Athetoid cerebral palsy

  • Residual effects of neonatal anoxia

• Gait abnormalities and progressive postural changes are often early indicators

Special Clinical Considerations

• Encourage adequate sleep and minimize emotional stress

• Avoid range-of-motion exercises that exacerbate dystonia

• Protect the patient from injury (padded bed rails, safe environment)

• Monitor for secondary complications: contractures, joint deformities, aspiration risk

Patient education & Counseling

• Explain the nature of dystonia and its chronic course

• Educate about treatment options: medications (anticholinergics, benzodiazepines, botulinum toxin injections), deep brain stimulation in selected cases

• Emphasize stress management, sleep hygiene, and supportive therapies

• Encourage participation in support groups and mental health services as needed

References

1. Andrews C, Aviles-Olmos I, Hariz M, Foltynie T. Which patients with dystonia benefit from deep brain stimulation? A metaregression of individual patient outcomes. J Neurol Neurosurg Psychiatry. 2010;81:1383–1389.

2. Brighina F, Romano M, Giglia G, Saia V, Puma A, Giglia F, et al. Effects of cerebellar TMS on motor cortex of patients with focal dystonia: A preliminary report. Exp Brain Res. 2009;192:651–656.

3. Fahn S, Jankovic J, Hallett M. Principles and Practice of Movement Disorders. 2nd ed. Philadelphia: Elsevier; 2011.

4. Albanese A, Bhatia K, Bressman SB, DeLong MR, Fahn S, Fung VS, et al. Phenomenology and classification of dystonia: A consensus update. Mov Disord. 2013;28:863–873.

5. Jankovic J. Treatment of dystonia. Lancet Neurol. 2006;5:864–872.