Is ballismus a very severe form of chorea characterized by violent flinging of the proximal extremities?

Ballismus: A Severe Form of Chorea

Yes, ballismus is indeed a severe form of chorea characterized by violent, high-amplitude, flinging movements that typically affect the proximal parts of the extremities. 1, 2

Clinical Characteristics and Differentiation

• Ballismus represents the most severe end of the chorea spectrum, distinguished by its large amplitude, proximal location, and violent, flinging quality of movements 1, 2
• While chorea refers to irregular, flowing, non-stereotyped, random involuntary movements that give an appearance of "dance-like" movements, ballismus specifically refers to these movements when they become proximal and of large amplitude 2
• Ballismus is often described as rapid, violent movements that involve throwing or flinging motions, typically affecting the proximal parts of the limbs 3
• The American Heart Association characterizes chorea as irregular, rapid movements that flow randomly, which can progress to the more severe ballistic movements 4

Clinical Presentation and Variants

• Ballismus most commonly presents as hemiballismus (affecting one side of the body), which is typically caused by contralateral lesions of the subthalamic nucleus or its connections 1
• The movements in ballismus are involuntary, violent, coarse, and have a wide amplitude, making them more disruptive than typical choreiform movements 5
• Like chorea, ballistic movements are typically worsened by anxiety and stress and subside during sleep 1
• Patients with ballismus often attempt to disguise the movements by incorporating them into purposeful activities, though this becomes increasingly difficult as severity increases 2

Etiology and Pathophysiology

• The most common causes of hemiballismus include:
  • Cerebrovascular disease (stroke) affecting the subthalamic nucleus 1
  • Metabolic disorders, particularly non-ketotic hyperglycemia in uncontrolled diabetes 5, 6
  • Other causes include infectious, autoimmune, and neurodegenerative conditions 7
• In a retrospective study of acute/subacute onset chorea/hemiballismus, 68.4% of patients presented with hemiballismus, with diabetes mellitus being a significant underlying factor in 68.42% of cases 6

Diagnostic Approach

• Brain MRI without contrast is the optimal imaging modality for patients with chorea/ballismus to identify structural causes 7
• Comprehensive metabolic evaluation is essential, particularly blood glucose and HbA1c levels, given the strong association with diabetes 6
• The American Academy of Neurology recommends differentiating ballismus/chorea from other movement disorders such as tics, which are typically briefer in duration 8

Management Considerations

• Treatment should primarily target the underlying cause, particularly focusing on glycemic control in cases related to diabetes 5
• Symptomatic treatment may include dopamine receptor blockers when symptoms are severe and disabling 5
• The American Academy of Neurology recommends periodic evaluation of patients receiving long-term neuroleptic treatment to monitor for tardive dyskinesia 8
• Surgical interventions are typically reserved for severe, persistent, and disabling hemiballismus that doesn't respond to medical management 5

Clinical Pitfalls and Caveats

• Misdiagnosis is common as ballismus may be confused with other movement disorders or even psychiatric conditions 4
• Ballismus can be the presenting symptom of serious underlying conditions like stroke or uncontrolled diabetes, making prompt diagnosis crucial 5, 6
• While ballismus is typically unilateral (hemiballismus), it can occasionally present bilaterally or be limited to a single extremity 6
• Spontaneous improvement or remission may occur with proper treatment of the underlying cause, particularly in cases related to metabolic disorders 5