Dystonia: Involuntary Muscle Contractions That Twist the Body — Causes and Treatment

Dystonia is a movement disorder characterised by sustained or intermittent muscle contractions causing abnormal, often repetitive movements or postures. The movements are typically patterned and twisted, and worsen with voluntary action (action-induced dystonia). Dystonia is not a spastic condition — the muscles have normal tone at rest in many forms — but the disorder of motor control causes inappropriate co-contraction of agonist and antagonist muscles, producing the characteristic twisting and sustained posturing.

Classification by Distribution

Focal dystonia: Affects a single body part. The most common forms in adults: Cervical dystonia (spasmodic torticollis) — the most common focal dystonia; involuntary head turning or tilting, often with neck pain; can be severely disabling. Blepharospasm — involuntary, forceful closure of the eyes; can cause functional blindness. Writer's cramp — task-specific dystonia; the hand cramps and adopts abnormal posture specifically during writing. Oromandibular dystonia — jaw and tongue movements causing difficulty speaking or chewing. Generalised dystonia: Typically begins in childhood (often one limb) and spreads to involve the entire body. DYT1 gene mutation (TOR1A) is the most common cause of childhood-onset generalised dystonia.

Secondary Dystonia

Dystonia can also occur secondary to: dopamine-blocking medications (metoclopramide, haloperidol — acute dystonic reaction within hours of first dose, or tardive dystonia after prolonged use); brain injury, stroke; Wilson's disease (copper accumulation — treatable cause of dystonia in young people — always exclude this in young-onset dystonia).

Treatment

Botulinum toxin injections: First-line for focal dystonias — OnabotulinumtoxinA injected into the overactive muscles every 12 weeks. Dramatically reduces symptoms in cervical dystonia and blepharospasm. Oral medications: Trihexyphenidyl (anticholinergic), clonazepam, baclofen. Deep brain stimulation (DBS): For refractory generalised dystonia — highly effective for DYT1 mutation. Sri Anand CNC, Chanda Nagar, Hyderabad. Call +91 90633 66983.