Hemiballismus is a rare and involuntary movement disorder characterized by sudden, violent, and flinging movements of one side of the body. It is caused by an abnormality in the basal ganglia, a group of structures deep within the brain involved in motor control. The term “hemiballismus” is derived from the Greek words “hemi” meaning half and “ballismus” meaning to throw or dance. The condition is typically unilateral, affecting one side of the body, and most commonly affects the arm and leg on the same side. The movements are often irregular, forceful, and uncontrolled, causing the affected limb to swing or flail uncontrollably.
Epidemiology
Hemiballismus is a rare movement disorder, accounting for less than 1% of all movement disorders. It commonly affects adults, especially those in their 50s to 70s. The most common cause is a stroke that damages the subthalamic nucleus, but other causes include vascular malformations, brain tumors, infections, metabolic disorders, and medications. Hemiballismus occurs in both genders and all ethnicities, with its prevalence influenced by the underlying conditions, such as stroke. Due to its rarity and diverse causes, comprehensive epidemiological data is limited, and more research is needed to understand its prevalence and risk factors.
Anatomy
Pathophysiology
Hemiballismus is characterized by abnormal and involuntary movements that result from dysfunction or damage to the basal ganglia, a collection of structures deep within the brain that are involved in motor control. The exact pathophysiology of hemiballismus is not fully understood, but it is believed to involve disruption of the normal inhibitory pathways within the basal ganglia circuitry. The basal ganglia play a crucial role in regulating voluntary movements by modulating the activity of the motor cortex. This circuitry involves a delicate balance between excitatory and inhibitory signals. The primary structures implicated in hemiballismus are the subthalamic nucleus (STN) and the globus pallidus interna (GPi). In normal circumstances, the STN receives excitatory inputs from the cortex and sends inhibitory signals to the GPi. The GPi, in turn, projects inhibitory signals to the thalamus, which helps regulate motor activity. This balanced activity ensures smooth and coordinated movements. In hemiballismus, there is disruption or dysfunction of this circuitry, leading to an imbalance between excitation and inhibition. The exact mechanisms by which this imbalance occurs can vary depending on the underlying cause of hemiballismus. One common cause of hemiballismus is damage to the subthalamic nucleus (STN), such as due to a vascular event like a stroke or a vascular malformation. This damage can result in reduced inhibitory output from the STN to the GPi, leading to increased activity and disinhibition of the thalamus. The thalamus then becomes hyperactive and sends excessive excitatory signals to the motor cortex, resulting in the involuntary and abnormal movements seen in hemiballismus. Other causes of hemiballismus, such as brain tumors, infections, or metabolic disorders, can also disrupt the normal basal ganglia circuitry and lead to similar imbalances between excitation and inhibition. It is important to note that hemiballismus is often a symptom of an underlying condition rather than a primary disorder. The pathophysiology of hemiballismus is therefore closely linked to the underlying cause, and the specific mechanisms may vary depending on the individual case. Further research is needed to fully understand the complex pathophysiology of hemiballismus and the underlying mechanisms that lead to the abnormal movements observed in affected individuals.
Etiology
Hemiballismus is a movement disorder that can be caused by various underlying conditions or factors. The etiology of hemiballismus is often associated with dysfunction or damage to the basal ganglia, particularly the subthalamic nucleus (STN) and its connections. Here are some common etiological factors associated with hemiballismus:
Vascular Events: The most common cause of hemiballismus is a vascular event, such as a stroke or a vascular malformation. Interruption of blood flow to the basal ganglia, including the STN, can lead to dysfunction and result in the characteristic involuntary movements.
Structural Lesions: Hemiballismus can also be caused by structural abnormalities or lesions in the basal ganglia or related areas. This includes brain tumors (such as those in the subthalamic region), vascular malformations, or other space-occupying lesions that directly affect the basal ganglia or disrupt its connections.
Metabolic Disorders: Certain metabolic disorders, such as hyperglycemia (high blood sugar) or non-ketotic hyperosmolar state, can cause hemiballismus. These metabolic disturbances can result in dysfunction within the basal ganglia circuitry and lead to the abnormal movements.
Infections: In rare cases, infections affecting the basal ganglia or related structures can contribute to the development of hemiballismus. This may include viral encephalitis or other infectious processes that involve the central nervous system.
Medications: Hemiballismus can be induced or exacerbated by certain medications, although this is relatively uncommon. Medications that have been reported to trigger hemiballismus include dopamine-blocking agents, such as antipsychotic medications.
Unknown (Idiopathic): In some instances, the underlying cause of hemiballismus remains unknown, and the condition is classified as idiopathic. This occurs when no identifiable structural, vascular, metabolic, infectious, or medication-related causes are evident.
Prognosis
The prognosis of hemiballismus varies based on factors like the cause, severity, and treatment response. If caused by a reversible condition (e.g., metabolic disorders or medication), symptoms may improve with treatment. However, if due to irreversible causes like stroke or neurodegenerative diseases, the prognosis can be worse. Treatment response plays a key role, with some individuals experiencing symptom relief and better quality of life, while others may need ongoing management. The degree of functional impairment also affects long-term outcomes, as does the presence of complications like falls or psychological distress. The underlying neurological condition also impacts the prognosis.
Genetics
Prognostic Factors
The prognosis of hemiballismus depends on several factors, including the underlying cause, the severity of symptoms, and the response to treatment. In some cases, hemiballismus may be transient and resolve on its own, while in others, it may be chronic or persistent. Here are some factors that can influence the prognosis:
Underlying Cause: The prognosis can be influenced by the underlying cause of hemiballismus. For example, if the cause is a reversible condition such as a metabolic disorder or medication-induced, treating the underlying cause may lead to resolution of symptoms and a good prognosis. On the other hand, if the underlying cause is an irreversible condition like a stroke or a progressive neurodegenerative disorder, the prognosis may be more guarded.
Treatment Response: The response to treatment can significantly impact the prognosis. Some individuals with hemiballismus may experience a significant reduction in symptoms with appropriate treatment, leading to improved functional abilities and quality of life. However, others may have a limited response to treatment or require ongoing management to control symptoms.
Functional Impairment: The degree of functional impairment caused by hemiballismus can vary among individuals. Some patients may have minimal impact on daily activities, while others may experience significant limitations in movement, coordination, and overall functioning. The severity of functional impairment can influence the long-term prognosis and the individual’s ability to perform daily tasks independently.
Underlying Neurological Condition: Hemiballismus can be associated with various underlying neurological conditions, such as strokes, tumors, or neurodegenerative disorders. The prognosis may be influenced by the specific characteristics and course of the underlying condition. For example, if the underlying condition is progressive and leads to further neurological deterioration, the long-term prognosis may be less favorable.
Complications: Hemiballismus can sometimes be associated with complications, such as falls, injuries, or secondary psychological distress. The occurrence of these complications can impact the overall prognosis and functional outcomes.
Clinical History
The clinical history of a patient with hemiballismus typically involves a detailed assessment of their symptoms, medical history, and potential risk factors.
Symptom Onset: Inquire about the timing and circumstances surrounding the onset of abnormal movements. Determine if the hemiballismus developed suddenly or gradually, and whether there was an identifiable trigger or event preceding its onset.
Description of Abnormal Movements: Obtain a detailed description of the abnormal movements observed. Hemiballismus is characterized by involuntary, sudden, and forceful flinging movements typically affecting one side of the body. Note the body parts involved (e.g., arm, leg), the amplitude and speed of the movements, and any associated features such as restlessness or difficulty controlling the affected limb.
Unilateral Presentation: Hemiballismus is typically unilateral, affecting one side of the body. Assess whether the abnormal movements are limited to one side or if they have spread to involve both sides.
Duration and Frequency: Determine the duration and frequency of the hemiballismus episodes. Note whether the movements are continuous or intermittent, and if there are any factors that exacerbate or alleviate the symptoms.
Associated Symptoms: Inquire about the presence of any additional symptoms or neurological abnormalities. These may include muscle weakness, altered sensation, changes in coordination, or other movement disorders.
Medical History: Evaluate the patient’s medical history for any underlying conditions that could contribute to the development of hemiballismus. This may include previous strokes, brain tumors, vascular malformations, metabolic disorders, infections, or medication use.
Family History: Assess whether there is a family history of movement disorders or neurological conditions, as some forms of hemiballismus can be hereditary.
Medications and Substances: Determine if the patient is taking any medications, including dopamine-blocking agents, which can sometimes induce or worsen hemiballismus. Also, ask about substance use, as certain drugs or toxins may contribute to movement abnormalities.
Functional Impact: Assess how the hemiballismus affects the patient’s daily activities, functional abilities, and overall quality of life.
Age group
Hemiballismus most commonly affects older adults, particularly those over 50–60 years old. It is often associated with vascular events, such as stroke, which are more prevalent in this age group. However, it can also occur in younger individuals due to metabolic disorders (e.g., nonketotic hyperglycemia), traumatic brain injury, tumors, or infections affecting the subthalamic nucleus or its connections.
Physical Examination
During the physical examination of a patient with hemiballismus, the focus is on assessing the characteristic abnormal movements, evaluating associated neurological findings, and searching for potential underlying causes.
key components of the physical examination:
Observation of Abnormal Movements
Neurological Examination
Cranial Nerve Examination
Balance and Coordination Assessment
Muscle Tone and Power
Sensory Examination
Evaluation of Reflexes
Examination of Additional Systems
Hemiballismus typically presents acutely, with sudden onset of involuntary, violent, and flinging movements of one side of the body. It is most caused by a lesion in the subthalamic nucleus, often due to a stroke. The severity can vary, but the abrupt onset and intense movements often require urgent medical evaluation and management.
Differential Diagnoses
Huntington’s Disease
Wilson’s Disease
Sydenham’s Chorea
Hyperglycemic Hemichorea-Hemiballismus Syndrome
Lesions or Tumors
Psychogenic Movement Disorders
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
Symptomatic Management Since hemiballismus can be disabling, pharmacologic and non-pharmacologic approaches are used to control symptoms.
Dopamine Blockade (First-Line Therapy)
Dopamine Depleters (Alternative First-Line or Adjunctive) Tetrabenazine or Valbenazine (VMAT2 inhibitors) – reduce dopamine release, effective with fewer extrapyramidal side effects.
GABAergic Modulation Benzodiazepines (e.g., Clonazepam, Diazepam): Used for their muscle-relaxant and sedative effects.
Baclofen: GABA-B agonist sometimes used adjunctively.
Refractory Cases For persistent or severe hemiballismus not responsive to medication:
Deep Brain Stimulation (DBS): STN or globus pallidus interna (GPi) targeting in severe, refractory cases.
Stereotactic Lesioning: Pallidotomy or thalamotomy in selected cases.
Supportive and Rehabilitation Therapy Physical and occupational therapy to improve function and prevent secondary complications.
Counselling and psychiatric support for quality-of-life improvement.
by Stage
by Modality
Chemotherapy
Radiation Therapy
Surgical Interventions
Hormone Therapy
Immunotherapy
Hyperthermia
Photodynamic Therapy
Stem Cell Transplant
Targeted Therapy
Palliative Care
lifestyle-modifications-for-hemiballismus
Fall and Injury Prevention
Padding and Cushioned Surfaces: Use padded furniture edges and place cushioned mats in high-risk areas.
Secure Loose Objects: Remove or secure fragile objects that could be knocked over.
Non-Slip Flooring: Use rugs with anti-slip backing and ensure floors are free of tripping hazards.
Adaptive Living Arrangements
Stable Seating: Use chairs with armrests and weighted bases to prevent tipping.
Bed Safety: Consider bed rails or lower beds to reduce fall risks during sleep.
Assistive Devices and Support
Mobility Aids: Canes, walkers, or wheelchairs may be necessary if mobility is significantly affected.
Weighted Utensils: Special utensils with added weight can help control unintentional movements while eating.
Treating the Underlying Cause
Stroke-related hemiballismus: Supportive care with rehabilitation, often self-limiting within weeks to months.
Metabolic causes (e.g., hyperglycemia): Correction of blood glucose levels, hydration, and electrolyte management.
Infections or inflammatory conditions: Appropriate antimicrobial or anti-inflammatory therapy.
Neoplastic or structural lesions: Neurosurgical evaluation if indicated.
Role of dopamine-blocking agents in treating Hemiballismus
Medications such as neuroleptics (e.g., haloperidol, risperidone) or tetrabenazine can help reduce abnormal movements by blocking dopamine receptors. However, these medications may have side effects and should be used cautiously.
Effectiveness of antiepileptic drugs in treating Hemiballismus
Certain antiepileptic medications, such as carbamazepine or valproic acid, may be considered in some cases to help control the abnormal movements.
Use of Botulinum Toxin Injections in treating Hemiballismus
Botulinum toxin injections can be used to selectively weaken or paralyze specific muscles involved in the abnormal movements. This can help reduce the severity and frequency of hemiballismus. However, the effect is temporary and repeat injections may be needed.
Hemiballismus is a rare and involuntary movement disorder characterized by sudden, violent, and flinging movements of one side of the body. It is caused by an abnormality in the basal ganglia, a group of structures deep within the brain involved in motor control. The term “hemiballismus” is derived from the Greek words “hemi” meaning half and “ballismus” meaning to throw or dance. The condition is typically unilateral, affecting one side of the body, and most commonly affects the arm and leg on the same side. The movements are often irregular, forceful, and uncontrolled, causing the affected limb to swing or flail uncontrollably.
Hemiballismus is a rare movement disorder, accounting for less than 1% of all movement disorders. It commonly affects adults, especially those in their 50s to 70s. The most common cause is a stroke that damages the subthalamic nucleus, but other causes include vascular malformations, brain tumors, infections, metabolic disorders, and medications. Hemiballismus occurs in both genders and all ethnicities, with its prevalence influenced by the underlying conditions, such as stroke. Due to its rarity and diverse causes, comprehensive epidemiological data is limited, and more research is needed to understand its prevalence and risk factors.
Hemiballismus is characterized by abnormal and involuntary movements that result from dysfunction or damage to the basal ganglia, a collection of structures deep within the brain that are involved in motor control. The exact pathophysiology of hemiballismus is not fully understood, but it is believed to involve disruption of the normal inhibitory pathways within the basal ganglia circuitry. The basal ganglia play a crucial role in regulating voluntary movements by modulating the activity of the motor cortex. This circuitry involves a delicate balance between excitatory and inhibitory signals. The primary structures implicated in hemiballismus are the subthalamic nucleus (STN) and the globus pallidus interna (GPi). In normal circumstances, the STN receives excitatory inputs from the cortex and sends inhibitory signals to the GPi. The GPi, in turn, projects inhibitory signals to the thalamus, which helps regulate motor activity. This balanced activity ensures smooth and coordinated movements. In hemiballismus, there is disruption or dysfunction of this circuitry, leading to an imbalance between excitation and inhibition. The exact mechanisms by which this imbalance occurs can vary depending on the underlying cause of hemiballismus. One common cause of hemiballismus is damage to the subthalamic nucleus (STN), such as due to a vascular event like a stroke or a vascular malformation. This damage can result in reduced inhibitory output from the STN to the GPi, leading to increased activity and disinhibition of the thalamus. The thalamus then becomes hyperactive and sends excessive excitatory signals to the motor cortex, resulting in the involuntary and abnormal movements seen in hemiballismus. Other causes of hemiballismus, such as brain tumors, infections, or metabolic disorders, can also disrupt the normal basal ganglia circuitry and lead to similar imbalances between excitation and inhibition. It is important to note that hemiballismus is often a symptom of an underlying condition rather than a primary disorder. The pathophysiology of hemiballismus is therefore closely linked to the underlying cause, and the specific mechanisms may vary depending on the individual case. Further research is needed to fully understand the complex pathophysiology of hemiballismus and the underlying mechanisms that lead to the abnormal movements observed in affected individuals.
Hemiballismus is a movement disorder that can be caused by various underlying conditions or factors. The etiology of hemiballismus is often associated with dysfunction or damage to the basal ganglia, particularly the subthalamic nucleus (STN) and its connections. Here are some common etiological factors associated with hemiballismus:
Vascular Events: The most common cause of hemiballismus is a vascular event, such as a stroke or a vascular malformation. Interruption of blood flow to the basal ganglia, including the STN, can lead to dysfunction and result in the characteristic involuntary movements.
Structural Lesions: Hemiballismus can also be caused by structural abnormalities or lesions in the basal ganglia or related areas. This includes brain tumors (such as those in the subthalamic region), vascular malformations, or other space-occupying lesions that directly affect the basal ganglia or disrupt its connections.
Metabolic Disorders: Certain metabolic disorders, such as hyperglycemia (high blood sugar) or non-ketotic hyperosmolar state, can cause hemiballismus. These metabolic disturbances can result in dysfunction within the basal ganglia circuitry and lead to the abnormal movements.
Infections: In rare cases, infections affecting the basal ganglia or related structures can contribute to the development of hemiballismus. This may include viral encephalitis or other infectious processes that involve the central nervous system.
Medications: Hemiballismus can be induced or exacerbated by certain medications, although this is relatively uncommon. Medications that have been reported to trigger hemiballismus include dopamine-blocking agents, such as antipsychotic medications.
Unknown (Idiopathic): In some instances, the underlying cause of hemiballismus remains unknown, and the condition is classified as idiopathic. This occurs when no identifiable structural, vascular, metabolic, infectious, or medication-related causes are evident.
Prognosis
The prognosis of hemiballismus varies based on factors like the cause, severity, and treatment response. If caused by a reversible condition (e.g., metabolic disorders or medication), symptoms may improve with treatment. However, if due to irreversible causes like stroke or neurodegenerative diseases, the prognosis can be worse. Treatment response plays a key role, with some individuals experiencing symptom relief and better quality of life, while others may need ongoing management. The degree of functional impairment also affects long-term outcomes, as does the presence of complications like falls or psychological distress. The underlying neurological condition also impacts the prognosis.
The prognosis of hemiballismus depends on several factors, including the underlying cause, the severity of symptoms, and the response to treatment. In some cases, hemiballismus may be transient and resolve on its own, while in others, it may be chronic or persistent. Here are some factors that can influence the prognosis:
Underlying Cause: The prognosis can be influenced by the underlying cause of hemiballismus. For example, if the cause is a reversible condition such as a metabolic disorder or medication-induced, treating the underlying cause may lead to resolution of symptoms and a good prognosis. On the other hand, if the underlying cause is an irreversible condition like a stroke or a progressive neurodegenerative disorder, the prognosis may be more guarded.
Treatment Response: The response to treatment can significantly impact the prognosis. Some individuals with hemiballismus may experience a significant reduction in symptoms with appropriate treatment, leading to improved functional abilities and quality of life. However, others may have a limited response to treatment or require ongoing management to control symptoms.
Functional Impairment: The degree of functional impairment caused by hemiballismus can vary among individuals. Some patients may have minimal impact on daily activities, while others may experience significant limitations in movement, coordination, and overall functioning. The severity of functional impairment can influence the long-term prognosis and the individual’s ability to perform daily tasks independently.
Underlying Neurological Condition: Hemiballismus can be associated with various underlying neurological conditions, such as strokes, tumors, or neurodegenerative disorders. The prognosis may be influenced by the specific characteristics and course of the underlying condition. For example, if the underlying condition is progressive and leads to further neurological deterioration, the long-term prognosis may be less favorable.
Complications: Hemiballismus can sometimes be associated with complications, such as falls, injuries, or secondary psychological distress. The occurrence of these complications can impact the overall prognosis and functional outcomes.
The clinical history of a patient with hemiballismus typically involves a detailed assessment of their symptoms, medical history, and potential risk factors.
Symptom Onset: Inquire about the timing and circumstances surrounding the onset of abnormal movements. Determine if the hemiballismus developed suddenly or gradually, and whether there was an identifiable trigger or event preceding its onset.
Description of Abnormal Movements: Obtain a detailed description of the abnormal movements observed. Hemiballismus is characterized by involuntary, sudden, and forceful flinging movements typically affecting one side of the body. Note the body parts involved (e.g., arm, leg), the amplitude and speed of the movements, and any associated features such as restlessness or difficulty controlling the affected limb.
Unilateral Presentation: Hemiballismus is typically unilateral, affecting one side of the body. Assess whether the abnormal movements are limited to one side or if they have spread to involve both sides.
Duration and Frequency: Determine the duration and frequency of the hemiballismus episodes. Note whether the movements are continuous or intermittent, and if there are any factors that exacerbate or alleviate the symptoms.
Associated Symptoms: Inquire about the presence of any additional symptoms or neurological abnormalities. These may include muscle weakness, altered sensation, changes in coordination, or other movement disorders.
Medical History: Evaluate the patient’s medical history for any underlying conditions that could contribute to the development of hemiballismus. This may include previous strokes, brain tumors, vascular malformations, metabolic disorders, infections, or medication use.
Family History: Assess whether there is a family history of movement disorders or neurological conditions, as some forms of hemiballismus can be hereditary.
Medications and Substances: Determine if the patient is taking any medications, including dopamine-blocking agents, which can sometimes induce or worsen hemiballismus. Also, ask about substance use, as certain drugs or toxins may contribute to movement abnormalities.
Functional Impact: Assess how the hemiballismus affects the patient’s daily activities, functional abilities, and overall quality of life.
Age group
Hemiballismus most commonly affects older adults, particularly those over 50–60 years old. It is often associated with vascular events, such as stroke, which are more prevalent in this age group. However, it can also occur in younger individuals due to metabolic disorders (e.g., nonketotic hyperglycemia), traumatic brain injury, tumors, or infections affecting the subthalamic nucleus or its connections.
During the physical examination of a patient with hemiballismus, the focus is on assessing the characteristic abnormal movements, evaluating associated neurological findings, and searching for potential underlying causes.
key components of the physical examination:
Observation of Abnormal Movements
Neurological Examination
Cranial Nerve Examination
Balance and Coordination Assessment
Muscle Tone and Power
Sensory Examination
Evaluation of Reflexes
Examination of Additional Systems
Hemiballismus typically presents acutely, with sudden onset of involuntary, violent, and flinging movements of one side of the body. It is most caused by a lesion in the subthalamic nucleus, often due to a stroke. The severity can vary, but the abrupt onset and intense movements often require urgent medical evaluation and management.
Huntington’s Disease
Wilson’s Disease
Sydenham’s Chorea
Hyperglycemic Hemichorea-Hemiballismus Syndrome
Lesions or Tumors
Psychogenic Movement Disorders
Symptomatic Management Since hemiballismus can be disabling, pharmacologic and non-pharmacologic approaches are used to control symptoms.
Dopamine Blockade (First-Line Therapy)
Dopamine Depleters (Alternative First-Line or Adjunctive) Tetrabenazine or Valbenazine (VMAT2 inhibitors) – reduce dopamine release, effective with fewer extrapyramidal side effects.
GABAergic Modulation Benzodiazepines (e.g., Clonazepam, Diazepam): Used for their muscle-relaxant and sedative effects.
Baclofen: GABA-B agonist sometimes used adjunctively.
Refractory Cases For persistent or severe hemiballismus not responsive to medication:
Deep Brain Stimulation (DBS): STN or globus pallidus interna (GPi) targeting in severe, refractory cases.
Stereotactic Lesioning: Pallidotomy or thalamotomy in selected cases.
Supportive and Rehabilitation Therapy Physical and occupational therapy to improve function and prevent secondary complications.
Counselling and psychiatric support for quality-of-life improvement.
Neurology
Fall and Injury Prevention
Padding and Cushioned Surfaces: Use padded furniture edges and place cushioned mats in high-risk areas.
Secure Loose Objects: Remove or secure fragile objects that could be knocked over.
Non-Slip Flooring: Use rugs with anti-slip backing and ensure floors are free of tripping hazards.
Adaptive Living Arrangements
Stable Seating: Use chairs with armrests and weighted bases to prevent tipping.
Bed Safety: Consider bed rails or lower beds to reduce fall risks during sleep.
Assistive Devices and Support
Mobility Aids: Canes, walkers, or wheelchairs may be necessary if mobility is significantly affected.
Weighted Utensils: Special utensils with added weight can help control unintentional movements while eating.
Treating the Underlying Cause
Stroke-related hemiballismus: Supportive care with rehabilitation, often self-limiting within weeks to months.
Metabolic causes (e.g., hyperglycemia): Correction of blood glucose levels, hydration, and electrolyte management.
Infections or inflammatory conditions: Appropriate antimicrobial or anti-inflammatory therapy.
Neoplastic or structural lesions: Neurosurgical evaluation if indicated.
Neurology
Medications such as neuroleptics (e.g., haloperidol, risperidone) or tetrabenazine can help reduce abnormal movements by blocking dopamine receptors. However, these medications may have side effects and should be used cautiously.
Neurology
Certain antiepileptic medications, such as carbamazepine or valproic acid, may be considered in some cases to help control the abnormal movements.
Neurology
Botulinum toxin injections can be used to selectively weaken or paralyze specific muscles involved in the abnormal movements. This can help reduce the severity and frequency of hemiballismus. However, the effect is temporary and repeat injections may be needed.
Neurology
Surgical Options:
Deep Brain Stimulation (DBS)
The most common modern surgical approach.
Targets the subthalamic nucleus (STN) or globus pallidus internus (GPi).
A pacemaker-like device delivers electrical impulses to modulate abnormal brain activity.
Advantage: Adjustable, reversible, and has been effective in reducing symptoms.
Pallidotomy (Globus Pallidus Lesioning)
A lesion is created in the internal segment of the globus pallidus (GPi) to reduce abnormal movement.
Used when DBS is not available or feasible.
Can provide permanent symptom relief but is non-reversible.
Thalamotomy
Less commonly used, involves lesioning the ventral intermediate nucleus (VIM) of the thalamus.
May be considered in some cases where other targets are less effective.
Neurology
Acute Phase (Symptomatic Control)
Dopamine blockade: First-line treatment with antipsychotics (e.g., haloperidol) or dopamine-depleting agents (e.g., tetrabenazine).
GABAergic agents: Benzodiazepines or anticonvulsants (e.g., clonazepam, valproate) to reduce hyperkinetic movements.
Supportive care: Prevent complications like falls and injuries.
Identification & Treatment of Underlying Cause
Neuroimaging (MRI/CT): To identify stroke, tumor, infection, or metabolic causes.
Hemiballismus is a rare and involuntary movement disorder characterized by sudden, violent, and flinging movements of one side of the body. It is caused by an abnormality in the basal ganglia, a group of structures deep within the brain involved in motor control. The term “hemiballismus” is derived from the Greek words “hemi” meaning half and “ballismus” meaning to throw or dance. The condition is typically unilateral, affecting one side of the body, and most commonly affects the arm and leg on the same side. The movements are often irregular, forceful, and uncontrolled, causing the affected limb to swing or flail uncontrollably.
Hemiballismus is a rare movement disorder, accounting for less than 1% of all movement disorders. It commonly affects adults, especially those in their 50s to 70s. The most common cause is a stroke that damages the subthalamic nucleus, but other causes include vascular malformations, brain tumors, infections, metabolic disorders, and medications. Hemiballismus occurs in both genders and all ethnicities, with its prevalence influenced by the underlying conditions, such as stroke. Due to its rarity and diverse causes, comprehensive epidemiological data is limited, and more research is needed to understand its prevalence and risk factors.
Hemiballismus is characterized by abnormal and involuntary movements that result from dysfunction or damage to the basal ganglia, a collection of structures deep within the brain that are involved in motor control. The exact pathophysiology of hemiballismus is not fully understood, but it is believed to involve disruption of the normal inhibitory pathways within the basal ganglia circuitry. The basal ganglia play a crucial role in regulating voluntary movements by modulating the activity of the motor cortex. This circuitry involves a delicate balance between excitatory and inhibitory signals. The primary structures implicated in hemiballismus are the subthalamic nucleus (STN) and the globus pallidus interna (GPi). In normal circumstances, the STN receives excitatory inputs from the cortex and sends inhibitory signals to the GPi. The GPi, in turn, projects inhibitory signals to the thalamus, which helps regulate motor activity. This balanced activity ensures smooth and coordinated movements. In hemiballismus, there is disruption or dysfunction of this circuitry, leading to an imbalance between excitation and inhibition. The exact mechanisms by which this imbalance occurs can vary depending on the underlying cause of hemiballismus. One common cause of hemiballismus is damage to the subthalamic nucleus (STN), such as due to a vascular event like a stroke or a vascular malformation. This damage can result in reduced inhibitory output from the STN to the GPi, leading to increased activity and disinhibition of the thalamus. The thalamus then becomes hyperactive and sends excessive excitatory signals to the motor cortex, resulting in the involuntary and abnormal movements seen in hemiballismus. Other causes of hemiballismus, such as brain tumors, infections, or metabolic disorders, can also disrupt the normal basal ganglia circuitry and lead to similar imbalances between excitation and inhibition. It is important to note that hemiballismus is often a symptom of an underlying condition rather than a primary disorder. The pathophysiology of hemiballismus is therefore closely linked to the underlying cause, and the specific mechanisms may vary depending on the individual case. Further research is needed to fully understand the complex pathophysiology of hemiballismus and the underlying mechanisms that lead to the abnormal movements observed in affected individuals.
Hemiballismus is a movement disorder that can be caused by various underlying conditions or factors. The etiology of hemiballismus is often associated with dysfunction or damage to the basal ganglia, particularly the subthalamic nucleus (STN) and its connections. Here are some common etiological factors associated with hemiballismus:
Vascular Events: The most common cause of hemiballismus is a vascular event, such as a stroke or a vascular malformation. Interruption of blood flow to the basal ganglia, including the STN, can lead to dysfunction and result in the characteristic involuntary movements.
Structural Lesions: Hemiballismus can also be caused by structural abnormalities or lesions in the basal ganglia or related areas. This includes brain tumors (such as those in the subthalamic region), vascular malformations, or other space-occupying lesions that directly affect the basal ganglia or disrupt its connections.
Metabolic Disorders: Certain metabolic disorders, such as hyperglycemia (high blood sugar) or non-ketotic hyperosmolar state, can cause hemiballismus. These metabolic disturbances can result in dysfunction within the basal ganglia circuitry and lead to the abnormal movements.
Infections: In rare cases, infections affecting the basal ganglia or related structures can contribute to the development of hemiballismus. This may include viral encephalitis or other infectious processes that involve the central nervous system.
Medications: Hemiballismus can be induced or exacerbated by certain medications, although this is relatively uncommon. Medications that have been reported to trigger hemiballismus include dopamine-blocking agents, such as antipsychotic medications.
Unknown (Idiopathic): In some instances, the underlying cause of hemiballismus remains unknown, and the condition is classified as idiopathic. This occurs when no identifiable structural, vascular, metabolic, infectious, or medication-related causes are evident.
Prognosis
The prognosis of hemiballismus varies based on factors like the cause, severity, and treatment response. If caused by a reversible condition (e.g., metabolic disorders or medication), symptoms may improve with treatment. However, if due to irreversible causes like stroke or neurodegenerative diseases, the prognosis can be worse. Treatment response plays a key role, with some individuals experiencing symptom relief and better quality of life, while others may need ongoing management. The degree of functional impairment also affects long-term outcomes, as does the presence of complications like falls or psychological distress. The underlying neurological condition also impacts the prognosis.
The prognosis of hemiballismus depends on several factors, including the underlying cause, the severity of symptoms, and the response to treatment. In some cases, hemiballismus may be transient and resolve on its own, while in others, it may be chronic or persistent. Here are some factors that can influence the prognosis:
Underlying Cause: The prognosis can be influenced by the underlying cause of hemiballismus. For example, if the cause is a reversible condition such as a metabolic disorder or medication-induced, treating the underlying cause may lead to resolution of symptoms and a good prognosis. On the other hand, if the underlying cause is an irreversible condition like a stroke or a progressive neurodegenerative disorder, the prognosis may be more guarded.
Treatment Response: The response to treatment can significantly impact the prognosis. Some individuals with hemiballismus may experience a significant reduction in symptoms with appropriate treatment, leading to improved functional abilities and quality of life. However, others may have a limited response to treatment or require ongoing management to control symptoms.
Functional Impairment: The degree of functional impairment caused by hemiballismus can vary among individuals. Some patients may have minimal impact on daily activities, while others may experience significant limitations in movement, coordination, and overall functioning. The severity of functional impairment can influence the long-term prognosis and the individual’s ability to perform daily tasks independently.
Underlying Neurological Condition: Hemiballismus can be associated with various underlying neurological conditions, such as strokes, tumors, or neurodegenerative disorders. The prognosis may be influenced by the specific characteristics and course of the underlying condition. For example, if the underlying condition is progressive and leads to further neurological deterioration, the long-term prognosis may be less favorable.
Complications: Hemiballismus can sometimes be associated with complications, such as falls, injuries, or secondary psychological distress. The occurrence of these complications can impact the overall prognosis and functional outcomes.
The clinical history of a patient with hemiballismus typically involves a detailed assessment of their symptoms, medical history, and potential risk factors.
Symptom Onset: Inquire about the timing and circumstances surrounding the onset of abnormal movements. Determine if the hemiballismus developed suddenly or gradually, and whether there was an identifiable trigger or event preceding its onset.
Description of Abnormal Movements: Obtain a detailed description of the abnormal movements observed. Hemiballismus is characterized by involuntary, sudden, and forceful flinging movements typically affecting one side of the body. Note the body parts involved (e.g., arm, leg), the amplitude and speed of the movements, and any associated features such as restlessness or difficulty controlling the affected limb.
Unilateral Presentation: Hemiballismus is typically unilateral, affecting one side of the body. Assess whether the abnormal movements are limited to one side or if they have spread to involve both sides.
Duration and Frequency: Determine the duration and frequency of the hemiballismus episodes. Note whether the movements are continuous or intermittent, and if there are any factors that exacerbate or alleviate the symptoms.
Associated Symptoms: Inquire about the presence of any additional symptoms or neurological abnormalities. These may include muscle weakness, altered sensation, changes in coordination, or other movement disorders.
Medical History: Evaluate the patient’s medical history for any underlying conditions that could contribute to the development of hemiballismus. This may include previous strokes, brain tumors, vascular malformations, metabolic disorders, infections, or medication use.
Family History: Assess whether there is a family history of movement disorders or neurological conditions, as some forms of hemiballismus can be hereditary.
Medications and Substances: Determine if the patient is taking any medications, including dopamine-blocking agents, which can sometimes induce or worsen hemiballismus. Also, ask about substance use, as certain drugs or toxins may contribute to movement abnormalities.
Functional Impact: Assess how the hemiballismus affects the patient’s daily activities, functional abilities, and overall quality of life.
Age group
Hemiballismus most commonly affects older adults, particularly those over 50–60 years old. It is often associated with vascular events, such as stroke, which are more prevalent in this age group. However, it can also occur in younger individuals due to metabolic disorders (e.g., nonketotic hyperglycemia), traumatic brain injury, tumors, or infections affecting the subthalamic nucleus or its connections.
During the physical examination of a patient with hemiballismus, the focus is on assessing the characteristic abnormal movements, evaluating associated neurological findings, and searching for potential underlying causes.
key components of the physical examination:
Observation of Abnormal Movements
Neurological Examination
Cranial Nerve Examination
Balance and Coordination Assessment
Muscle Tone and Power
Sensory Examination
Evaluation of Reflexes
Examination of Additional Systems
Hemiballismus typically presents acutely, with sudden onset of involuntary, violent, and flinging movements of one side of the body. It is most caused by a lesion in the subthalamic nucleus, often due to a stroke. The severity can vary, but the abrupt onset and intense movements often require urgent medical evaluation and management.
Huntington’s Disease
Wilson’s Disease
Sydenham’s Chorea
Hyperglycemic Hemichorea-Hemiballismus Syndrome
Lesions or Tumors
Psychogenic Movement Disorders
Symptomatic Management Since hemiballismus can be disabling, pharmacologic and non-pharmacologic approaches are used to control symptoms.
Dopamine Blockade (First-Line Therapy)
Dopamine Depleters (Alternative First-Line or Adjunctive) Tetrabenazine or Valbenazine (VMAT2 inhibitors) – reduce dopamine release, effective with fewer extrapyramidal side effects.
GABAergic Modulation Benzodiazepines (e.g., Clonazepam, Diazepam): Used for their muscle-relaxant and sedative effects.
Baclofen: GABA-B agonist sometimes used adjunctively.
Refractory Cases For persistent or severe hemiballismus not responsive to medication:
Deep Brain Stimulation (DBS): STN or globus pallidus interna (GPi) targeting in severe, refractory cases.
Stereotactic Lesioning: Pallidotomy or thalamotomy in selected cases.
Supportive and Rehabilitation Therapy Physical and occupational therapy to improve function and prevent secondary complications.
Counselling and psychiatric support for quality-of-life improvement.
Neurology
Fall and Injury Prevention
Padding and Cushioned Surfaces: Use padded furniture edges and place cushioned mats in high-risk areas.
Secure Loose Objects: Remove or secure fragile objects that could be knocked over.
Non-Slip Flooring: Use rugs with anti-slip backing and ensure floors are free of tripping hazards.
Adaptive Living Arrangements
Stable Seating: Use chairs with armrests and weighted bases to prevent tipping.
Bed Safety: Consider bed rails or lower beds to reduce fall risks during sleep.
Assistive Devices and Support
Mobility Aids: Canes, walkers, or wheelchairs may be necessary if mobility is significantly affected.
Weighted Utensils: Special utensils with added weight can help control unintentional movements while eating.
Treating the Underlying Cause
Stroke-related hemiballismus: Supportive care with rehabilitation, often self-limiting within weeks to months.
Metabolic causes (e.g., hyperglycemia): Correction of blood glucose levels, hydration, and electrolyte management.
Infections or inflammatory conditions: Appropriate antimicrobial or anti-inflammatory therapy.
Neoplastic or structural lesions: Neurosurgical evaluation if indicated.
Neurology
Medications such as neuroleptics (e.g., haloperidol, risperidone) or tetrabenazine can help reduce abnormal movements by blocking dopamine receptors. However, these medications may have side effects and should be used cautiously.
Neurology
Certain antiepileptic medications, such as carbamazepine or valproic acid, may be considered in some cases to help control the abnormal movements.
Neurology
Botulinum toxin injections can be used to selectively weaken or paralyze specific muscles involved in the abnormal movements. This can help reduce the severity and frequency of hemiballismus. However, the effect is temporary and repeat injections may be needed.
Neurology
Surgical Options:
Deep Brain Stimulation (DBS)
The most common modern surgical approach.
Targets the subthalamic nucleus (STN) or globus pallidus internus (GPi).
A pacemaker-like device delivers electrical impulses to modulate abnormal brain activity.
Advantage: Adjustable, reversible, and has been effective in reducing symptoms.
Pallidotomy (Globus Pallidus Lesioning)
A lesion is created in the internal segment of the globus pallidus (GPi) to reduce abnormal movement.
Used when DBS is not available or feasible.
Can provide permanent symptom relief but is non-reversible.
Thalamotomy
Less commonly used, involves lesioning the ventral intermediate nucleus (VIM) of the thalamus.
May be considered in some cases where other targets are less effective.
Neurology
Acute Phase (Symptomatic Control)
Dopamine blockade: First-line treatment with antipsychotics (e.g., haloperidol) or dopamine-depleting agents (e.g., tetrabenazine).
GABAergic agents: Benzodiazepines or anticonvulsants (e.g., clonazepam, valproate) to reduce hyperkinetic movements.
Supportive care: Prevent complications like falls and injuries.
Identification & Treatment of Underlying Cause
Neuroimaging (MRI/CT): To identify stroke, tumor, infection, or metabolic causes.
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