dystonia

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions that cause twisting patterns or abnormal postures. Symptoms may include repetitive movements, tremor, or patterned postures. Dystonia can affect a single body part (focal), adjacent regions (segmental), or most of the body (generalized), and it may begin in childhood or adulthood. Tasks or emotional stress can worsen symptoms, while movement may transiently relieve them.

Classification is based on distribution and cause. Focal dystonias include cervical dystonia and blepharospasm; segmental dystonia involves two or more adjacent regions; generalized dystonia affects large parts or the whole body. Primary (idiopathic) dystonias have no other neurological signs and often have a genetic basis; secondary dystonias arise from brain injury, drugs, or other diseases.

Pathophysiology is not fully understood, but dystonia is thought to involve dysregulated motor circuits in the basal ganglia, thalamus, cerebellum, and sensorimotor cortex. Abnormal inhibition and maladaptive plasticity in these networks contribute to sustained contractions and abnormal postures.

Diagnosis is clinical, based on history and examination. Imaging and genetic testing may be used to exclude other conditions or identify hereditary forms. Treatments aim to reduce symptoms: botulinum toxin injections for focal dystonias; medications such as anticholinergics, baclofen, or benzodiazepines; physical therapy; and, in refractory generalized cases, deep brain stimulation of the globus pallidus internus.

Prognosis varies by type and cause. Many people achieve meaningful symptom relief with appropriate therapy, though dystonia is typically a chronic condition requiring ongoing management to optimize function and quality of life.