Hemichorea (also known as hemichorea) is a movement disorder characterized by involuntary, irregular, purposeless movements that resemble dance-like motions affecting one side of the body. The term derives from the Greek words "hemi-" (half) and "chorea" (dance), reflecting the characteristic dancing or jerky quality of the movements. [@shannon2009]
Hemichorea exists on a spectrum with hemiballismus, with both conditions resulting from dysfunction in the basal ganglia motor circuits, particularly involving the striatum and subthalamic nucleus. [@walker2011]
Clinical Presentation
Core Symptoms
Movement characteristics:
Random, irregular, jerky movements
Non-repetitive and non-rhythmic
Flowing quality (like piano playing)
Often continuous during waking hours
May decrease during sleep
Distribution:
Primarily affects the face, arm, and leg on one side
Can involve proximal and distal muscles
May vary in severity throughout the day
Associated Features
Motor impersistence: Inability to maintain sustained postures
Motor weakness: Often coexists with weakness on the affected side
Cognitive changes: May accompany cognitive impairment in neurodegenerative cases
Etiology
Vascular Causes (Most Common)
Stroke
Lacunar strokes affecting:
Striatum (putamen, caudate)
Subthalamic nucleus
Thalamus
Globus pallidus
Small vessel disease
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)
...
Hemichorea
Overview
Hemichorea (also known as hemichorea) is a movement disorder characterized by involuntary, irregular, purposeless movements that resemble dance-like motions affecting one side of the body. The term derives from the Greek words "hemi-" (half) and "chorea" (dance), reflecting the characteristic dancing or jerky quality of the movements. [@shannon2009]
Hemichorea exists on a spectrum with hemiballismus, with both conditions resulting from dysfunction in the basal ganglia motor circuits, particularly involving the striatum and subthalamic nucleus. [@walker2011]
Clinical Presentation
Core Symptoms
Movement characteristics:
Random, irregular, jerky movements
Non-repetitive and non-rhythmic
Flowing quality (like piano playing)
Often continuous during waking hours
May decrease during sleep
Distribution:
Primarily affects the face, arm, and leg on one side
Can involve proximal and distal muscles
May vary in severity throughout the day
Associated Features
Motor impersistence: Inability to maintain sustained postures
Motor weakness: Often coexists with weakness on the affected side
Cognitive changes: May accompany cognitive impairment in neurodegenerative cases
Etiology
Vascular Causes (Most Common)
Stroke
Lacunar strokes affecting:
Striatum (putamen, caudate)
Subthalamic nucleus
Thalamus
Globus pallidus
Small vessel disease
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)
Metabolic Causes
Non-ketotic hyperglycemia - Increasingly recognized cause in elderly patients
Hypoglycemia
Thyroid dysfunction (thyroid-related movement disorders)
Electrolyte disturbances:
Hyponatremia
Hypernatremia
Hypocalcemia
Neurodegenerative Diseases
Huntington's disease and Juvenile Huntington's disease
Wilson disease - Copper accumulation
Neuroacanthocytosis syndromes
C9orf72 expansions (ALS/FTD spectrum)
Autoimmune/Inflammatory
Systemic lupus erythematosus (SLE)
Autoimmune encephalitis
Antiphospholipid syndrome
CNS vasculitis
Infectious
HIV-associated encephalopathy
Syphilis (general paresis)
Viral encephalitis (post-infectious)
Drug-Induced
Levodopa-induced dyskinesias
Antipsychotic medications (tardive chorea)
Phenytoin
Oral contraceptives
Pathophysiology
Basal Ganglia Dysfunction
Hemichorea results from disruption of the normal inhibitory-excitatory balance in the basal ganglia motor circuit: [@postuma2003]
Mermaid diagram (expand to render)
Neurochemical Changes
Dopamine dysregulation: Either excess or deficiency
GABAergic dysfunction: Reduced inhibitory control
Cholinergic deficiency: Particularly in the striatum
Regional Involvement
Striatal lesions: Most common cause (especially putamen)
Subthalamic nucleus: More associated with ballismus
Thalamic involvement: Can produce chorea
Diagnosis
Clinical Evaluation
History:
Acute vs. gradual onset
Vascular risk factors
Medication history
Family history of movement disorders
Neurological examination:
Distribution of movements
Associated weakness
Cognitive assessment
Search for signs of systemic disease
Diagnostic Workup
Neuroimaging
MRI brain: Gold standard for structural lesions
T2/FLAIR hyperintensities (stroke,代谢)
Gradient echo (cavernous malformations)
CT brain: Acute hemorrhage
MR angiography: Vascular malformations
Laboratory Studies
Metabolic panel: Glucose, electrolytes, liver function
[Unknown, Shannon KM, Comella CL. Treatment of hyperkinetic movement disorders. Lancet Neurology. 2009 (2009)](https://pubmed.ncbi.nlm.nih.gov/19398973/)
[Unknown, Postuma RB, Lang AE. Hemiballismus: Consenting to treat. Neurology. 2003 (2003)](https://pubmed.ncbi.nlm.nih.gov/14504320/)
[Ceravolo R, et al., Non-ketotic hyperglycemia presenting with hemiballismus and hemichorea. Journal of Neurology. 2012 (2012)](https://pubmed.ncbi.nlm.nih.gov/22446854/)
[Unknown, Cardoso F. Chorea: A journey through history. Tremor and Other Hyperkinetic Movements. 2015 (2015)](https://pubmed.ncbi.nlm.nih.gov/26175779/)
[Unknown, Huntington Study Group. Tetrabenazine therapy for chorea. Neurology. 2006 (2006)](https://pubmed.ncbi.nlm.nih.gov/16476936/)
[Fasano A, et al., Surgical treatment of movement disorders. Journal of Neurology, Neurosurgery & Psychiatry. 2013 (2013)](https://pubmed.ncbi.nlm.nih.gov/23400136/)