atetosis

Atetosis, also spelled athetosis, is a movement disorder characterized by slow, continuous, involuntary writhing movements, most evident in the hands and face but can involve the limbs, trunk, and neck. The movements are often continuous, sinuous, and may become worse with voluntary action or stress; they can interfere with speaking, writing, and walking. Postural instability is common, and tone can fluctuate between hypotonia and dystonia.

Atetosis arises from dysfunction in the basal ganglia and their connections, particularly circuits involving the caudate, putamen, and thalamus. It may be congenital, as in certain forms of cerebral palsy, or acquired after perinatal hypoxic-ischemic injury, kernicterus, stroke, infection, or neurodegenerative disease. It can occur as part of choreoathetosis, a broader syndrome combining choreiform and athetoid movements.

Diagnosis is clinical, based on observation of movement patterns and history. Neuroimaging (MRI) and other tests may be used to identify underlying causes; EEG is not diagnostic for atetosis itself. Differential diagnosis includes chorea, dystonia, myoclonus, and tremor.

Treatment aims to manage symptoms and the underlying condition. For focal or troublesome movements, medications such as anticholinergics (e.g., trihexyphenidyl), benzodiazepines, baclofen, and vesicular monoamine transporter inhibitors (e.g., tetrabenazine) may be used. Botulinum toxin can help focal dystonia; deep brain stimulation of the internal globus pallidus may be considered in severe, disabling cases. Physical and occupational therapy support motor control and daily activities.

Prognosis varies with the underlying condition. In congenital cases, athetoid movements tend to persist but may improve in some individuals; in acquired etiologies, symptoms may lessen if the underlying brain injury is treated or stabilizes.