From the Guidelines
Athetosis is a complex movement disorder that requires a comprehensive diagnostic workup, including genetic testing and imaging, to determine the underlying cause, with suspected Huntington disease being a key consideration, as noted in the 2020 study by the American College of Radiology 1. When evaluating a patient with athetotic movements, it is essential to consider the broad differential diagnosis, including genetic and neurodegenerative disorders, as well as acquired conditions such as cerebrovascular, infectious, autoimmune, metabolic, and drug-induced syndromes. Key characteristics of athetosis include:
- Slow, writhing, involuntary movements
- Typically affects the hands, feet, face, and tongue
- Results from damage to the basal ganglia, particularly the putamen and globus pallidus
- Often continuous, flowing, and worm-like in appearance The diagnostic approach should involve:
- Genetic testing to determine the CAG repeat number for each allele, which is commercially available and the diagnostic test of choice for suspected Huntington disease 1
- Initial imaging, which may be normal early on in the disease course, but is essential to consider other potential etiologies Treatment of athetosis typically involves a multidisciplinary approach, including:
- Physical therapy to improve motor control
- Occupational therapy for daily living skills
- Medications like anticholinergics, benzodiazepines, or muscle relaxants to reduce abnormal movements
- Deep brain stimulation in severe cases The underlying mechanism of athetosis involves imbalances in neurotransmitters, particularly dopamine and acetylcholine, which disrupt normal movement control pathways in the brain, as seen in conditions like Huntington disease, where abnormal aggregates of the huntingtin protein accumulate in the brain and impair the function of transcription factors 1.
From the Research
Definition and Classification of Athetosis
- Athetosis is a peculiar involuntary movement resulting from pathologic involvement of the basal ganglia 2
- It is clinically differentiated from chorea and dystonia 2
- Athetosis is classified into double athetosis, chorea-athetosis, unilateral athetosis, and pseudo-athetosis 2
Treatment of Athetosis
- Stereotactic VL-thalamotomy is effective to relieve increased muscle tonus but not to decrease involuntary movement 2
- Muscle-tone-reducing procedures such as partial nerve block by lidocaine and surgical release of the neck muscles can reduce involuntary head movements in athetotic patients 3
- Botulinum toxin-A injections may be used to treat spasticity, but the effects are temporary, and adjunct physical therapies may be necessary to improve motor function 4
Associated Movement Disorders
- Athetosis is often associated with other movement disorders such as dystonia, chorea, and spasticity 5, 2
- Cerebral palsy is a common condition that can cause athetosis, dystonia, and other movement disorders 5