Movement Disorders in Pediatric Age

Introduction to Movement Disorders in Children

Movement disorders in children encompass a wide range of neurological conditions characterized by abnormal involuntary movements. Chorea, athetosis, myoclonus, and tremor are distinct types of movement disorders that can significantly impact a child's quality of life.

Key points:

These disorders can occur in isolation or as part of complex neurological syndromes.
Etiologies range from genetic and metabolic disorders to acquired conditions such as infections or autoimmune diseases.
Early recognition and accurate diagnosis are crucial for appropriate management and prognosis.
Treatment often requires a multidisciplinary approach, involving neurologists, geneticists, physiotherapists, and other specialists.

Chorea in Children

Chorea is characterized by rapid, unpredictable, dance-like movements that flow from one body part to another.

Clinical Features:

Irregular, non-rhythmic movements
Can affect any part of the body, but often involves the face, hands, and feet
Movements are typically brief and unsustained
May be exacerbated by stress or voluntary movements
Can interfere with daily activities and speech

Etiology:

Sydenham's chorea: Associated with Group A streptococcal infections
Genetic disorders:
- Huntington's disease (juvenile form)
- Benign hereditary chorea
- Wilson's disease
Autoimmune conditions:
- Systemic lupus erythematosus
- Antiphospholipid syndrome
Metabolic disorders: Lesch-Nyhan syndrome, glutaric aciduria
Vascular causes: Moyamoya disease, stroke
Drug-induced: Neuroleptics, anticonvulsants

Management Considerations:

Treatment of underlying cause when identified
Symptomatic treatment with dopamine-depleting agents (e.g., tetrabenazine) or dopamine receptor blockers (e.g., risperidone)
Physical and occupational therapy for functional improvement
Regular monitoring for disease progression and treatment side effects

Athetosis in Children

Athetosis involves slow, writhing, continuous movements, often occurring with chorea (choreoathetosis).

Clinical Features:

Slow, sinuous, writhing movements
Often affects the distal extremities, face, and trunk
Movements are typically more sustained than chorea
May be accompanied by fluctuations in muscle tone
Can significantly impair fine motor skills

Etiology:

Cerebral palsy: Particularly dyskinetic type
Kernicterus: Bilirubin-induced neurological dysfunction
Genetic disorders:
- Huntington's disease
- Wilson's disease
- Neurodegeneration with brain iron accumulation (NBIA)
Metabolic disorders: Glutaric aciduria, methylmalonic acidemia
Drug-induced: Tardive syndromes from neuroleptics

Management Considerations:

Address underlying cause when possible
Pharmacological treatments may include anticholinergics, dopamine receptor blockers, or tetrabenazine
Deep brain stimulation in severe cases
Intensive physical and occupational therapy
Adaptive devices and technologies to improve function

Myoclonus in Children

Myoclonus consists of brief, shock-like, involuntary muscle jerks or twitches.

Clinical Features:

Sudden, brief muscle contractions
Can be focal, multifocal, or generalized
May occur at rest, with action, or in response to stimuli
Can range from mild to severely disabling
May coexist with other movement disorders or seizures

Classification:

Physiological myoclonus: Normal phenomenon (e.g., hiccups, sleep jerks)
Essential myoclonus: Idiopathic, often familial
Epileptic myoclonus: Associated with epilepsy syndromes
Symptomatic myoclonus: Secondary to underlying neurological conditions

Etiology:

Epilepsy syndromes: Juvenile myoclonic epilepsy, Lennox-Gastaut syndrome
Neurodegenerative disorders: Lafora disease, neuronal ceroid lipofuscinosis
Metabolic disorders: Mitochondrial diseases, storage disorders
Infectious causes: Subacute sclerosing panencephalitis, Creutzfeldt-Jakob disease
Toxic-metabolic: Renal or hepatic failure, electrolyte imbalances
Drug-induced: Anticonvulsants, SSRIs, lithium

Management Considerations:

Treatment of underlying cause when identified
Pharmacological options include clonazepam, valproic acid, levetiracetam, and piracetam
Botulinum toxin injections for focal myoclonus
Dietary therapy (ketogenic diet) in some cases
Adaptive devices and occupational therapy for functional improvement

Tremor in Children

Tremor is a rhythmic, oscillatory movement of a body part, classified by its characteristics and context in which it occurs.

Clinical Features:

Rhythmic oscillations of a body part
Can be rest, postural, or action tremor
Frequency and amplitude may vary
Most commonly affects hands, but can involve head, voice, or other body parts
May interfere with fine motor tasks and activities of daily living

Classification:

Rest tremor: Present when body part is relaxed
Action tremor:
- Postural tremor: Present when maintaining a position against gravity
- Kinetic tremor: Occurs during voluntary movement
- Intention tremor: Worsens as approaching a target

Etiology:

Physiological tremor: Normal phenomenon, exacerbated by stress or caffeine
Essential tremor: Often familial, may begin in childhood
Cerebellar disorders: Infections, tumors, genetic ataxias
Wilson's disease: Copper metabolism disorder
Dystonic tremor: Associated with dystonia
Drug-induced: Beta-agonists, valproic acid, stimulants
Psychogenic tremor: Functional neurological disorder
Metabolic causes: Hyperthyroidism, hypoglycemia

Management Considerations:

Identify and treat underlying cause when possible
Pharmacological treatments may include propranolol, primidone, or topiramate
Botulinum toxin injections for focal tremors
Deep brain stimulation in severe, medication-resistant cases
Occupational therapy and adaptive devices to improve function
Lifestyle modifications (e.g., reducing caffeine intake, stress management)

Diagnosis of Movement Disorders in Children

Diagnosing movement disorders in children requires a comprehensive approach:

Clinical History:
- Detailed description of movements, including onset, progression, and exacerbating factors
- Family history
- Developmental history
- Associated symptoms (cognitive, behavioral changes)
Physical and Neurological Examination:
- Characterization of the movement disorder
- Assessment of other neurological signs
- Evaluation of cognitive function
Video Documentation:
- Helpful for accurate characterization and follow-up
Laboratory Studies:
- Complete blood count, metabolic panel
- Copper and ceruloplasmin levels (for Wilson's disease)
- Thyroid function tests
- Antistreptolysin O titer (for Sydenham's chorea)
Neuroimaging:
- MRI brain to evaluate structural abnormalities
- Functional neuroimaging (PET, SPECT) in selected cases
Genetic Testing:
- For suspected hereditary disorders
- May include targeted gene panels or whole exome sequencing
Electroencephalography (EEG):
- Particularly for myoclonus to differentiate cortical from subcortical origins
Electromyography (EMG) and Nerve Conduction Studies:
- To characterize tremor and myoclonus
Metabolic and Biochemical Testing:
- Urine organic acids, plasma amino acids
- Cerebrospinal fluid analysis in selected cases
Ophthalmological Examination:
- For Kayser-Fleischer rings in Wilson's disease

The diagnostic approach should be tailored to the specific clinical presentation and suspected underlying etiology. A multidisciplinary team including pediatric neurologists, geneticists, and metabolic specialists is often necessary for comprehensive evaluation and management.

Management of Movement Disorders in Children

Management of pediatric movement disorders is complex and often requires a multidisciplinary approach:

Pharmacological Treatments:
- Chorea: Dopamine-depleting agents (tetrabenazine), dopamine receptor blockers (risperidone)
- Athetosis: Anticholinergics, dopamine receptor blockers
- Myoclonus: Clonazepam, valproic acid, levetiracetam
- Tremor: Propranolol, primidone, topiramate
Non-pharmacological Interventions:
- Physical therapy: To improve motor function and prevent contractures
- Occupational therapy: For activities of daily living and fine motor skills
- Speech therapy: For dysarthria or dysphagia
- Adaptive devices: To enhance independence and function
Surgical Interventions:
- Deep Brain Stimulation (DBS): For severe, medication-resistant cases
- Selective dorsal rhizotomy: For spasticity in cerebral palsy
- Intrathecal baclofen pump: For severe generalized dystonia or spasticity
Botulinum Toxin Injections:
- For focal dystonia, spasticity, or tremor
- Can improve function and reduce pain
- Requires repeated injections at regular intervals
Dietary Interventions:
- Ketogenic diet: May be beneficial in certain metabolic disorders and refractory epilepsy with myoclonus
- Copper-restricted diet and zinc supplementation in Wilson's disease
- Avoiding triggers (e.g., caffeine) in essential tremor
Psychological Support:
- Cognitive-behavioral therapy to manage anxiety and depression
- Family counseling to address the impact on family dynamics
- Support groups for patients and families
Educational Interventions:
- Individualized Education Programs (IEPs) to address learning needs
- Assistive technology for academic tasks
- Teacher education about the child's condition and needs
Regular Monitoring:
- Follow-up assessments to evaluate treatment efficacy
- Monitoring for disease progression and treatment side effects
- Adjusting management plan as the child grows and develops
Transition Planning:
- Preparing adolescents for transition to adult healthcare services
- Vocational training and career counseling
- Planning for long-term care needs in progressive disorders

Challenges in Management:

Balancing efficacy of treatments with potential side effects, especially in developing children
Addressing the impact of the movement disorder on the child's overall development and quality of life
Managing expectations of families and adapting treatment goals as the condition evolves
Coordinating care among multiple specialists and therapists
Limited evidence base for many treatments in pediatric populations, necessitating individualized approaches

Effective management of pediatric movement disorders requires a holistic, patient-centered approach that addresses not only the physical symptoms but also the cognitive, emotional, and social aspects of the child's life. Regular reassessment and flexibility in treatment strategies are key to optimizing outcomes in these complex and often evolving conditions.

Introduction to Pediatric Ataxias

Ataxia is a neurological sign characterized by impaired coordination of voluntary movements. In the pediatric population, ataxias can present significant diagnostic and management challenges due to their diverse etiologies and clinical presentations. Ataxias in children can be acute, intermittent, or chronic, and may result from genetic, metabolic, infectious, or structural causes.

The underlying pathophysiology typically involves dysfunction of the cerebellum, its connections, or sensory pathways. Understanding the various forms of pediatric ataxias is crucial for early diagnosis, appropriate management, and improved patient outcomes.

Classification of Pediatric Ataxias

Pediatric ataxias can be classified based on various factors:

1. Temporal Pattern

Acute Ataxia: Sudden onset, often due to infections, intoxications, or trauma
Intermittent Ataxia: Episodic occurrences, seen in channelopathies or metabolic disorders
Chronic Ataxia: Persistent symptoms, often due to genetic or neurodegenerative conditions

2. Etiology

Genetic Ataxias:
- Autosomal Recessive Cerebellar Ataxias (e.g., Friedreich's ataxia)
- Autosomal Dominant Cerebellar Ataxias (e.g., Spinocerebellar ataxias)
- X-linked Ataxias (e.g., Fragile X-associated tremor/ataxia syndrome)
Acquired Ataxias:
- Infectious (e.g., cerebellitis, post-infectious ataxia)
- Toxic (e.g., medication-induced, alcohol intoxication)
- Structural (e.g., posterior fossa tumors, stroke)
- Autoimmune (e.g., opsoclonus-myoclonus syndrome)
Metabolic Ataxias: (e.g., mitochondrial disorders, lysosomal storage diseases)

Clinical Presentation of Pediatric Ataxias

The clinical presentation of ataxia in children can vary widely depending on the underlying cause and the areas of the nervous system affected. Common features include:

Gait Disturbances: Wide-based, unsteady gait; difficulty with tandem walking
Limb Incoordination: Impaired finger-to-nose and heel-to-shin testing
Dysarthria: Slurred, irregular speech
Nystagmus: Involuntary eye movements
Tremor: Intention tremor during voluntary movements
Dysdiadochokinesia: Difficulty performing rapid alternating movements

Additional symptoms may include:

Vertigo and dizziness
Cognitive impairment
Sensory deficits
Muscle weakness
Autonomic dysfunction

It's important to note that the presentation can be influenced by the child's age and developmental stage. In infants, ataxia may manifest as delayed motor milestones or hypotonia.

Diagnostic Approach to Pediatric Ataxias

Diagnosing pediatric ataxias requires a systematic approach:

1. Detailed History

Onset and progression of symptoms
Family history
Developmental milestones
Recent illnesses or vaccinations
Medication use or potential toxin exposure

2. Physical and Neurological Examination

Assessment of gait, coordination, and balance
Evaluation of cranial nerves
Testing of muscle strength and tone
Sensory examination
Cognitive assessment

3. Neuroimaging

MRI of the brain and spinal cord
CT scan in cases of suspected acute intracranial pathology

4. Laboratory Investigations

Complete blood count and metabolic panel
Cerebrospinal fluid analysis
Metabolic screening (e.g., lactate, pyruvate, amino acids)
Genetic testing for suspected hereditary ataxias

5. Specialized Tests

Electromyography (EMG) and nerve conduction studies
Evoked potentials
Ophthalmological evaluation
Audiometry

The diagnostic approach should be tailored to the individual patient, considering the clinical presentation and initial findings.

Treatment of Pediatric Ataxias

Treatment strategies for pediatric ataxias depend on the underlying cause and may include:

1. Targeted Therapies

Treatment of underlying infections or inflammatory conditions
Removal of offending toxins or medications
Surgical intervention for structural lesions
Specific treatments for certain genetic or metabolic disorders (e.g., vitamin E supplementation in ataxia with vitamin E deficiency)

2. Symptomatic Management

Medications to control associated symptoms (e.g., anti-epileptic drugs for seizures)
Physical therapy to improve balance and coordination
Occupational therapy for daily living activities
Speech therapy for dysarthria
Assistive devices (e.g., walkers, wheelchairs) as needed

3. Supportive Care

Nutritional support
Management of comorbidities
Psychological support for patients and families

4. Emerging Therapies

Gene therapy for certain genetic ataxias (in clinical trials)
Stem cell therapy (experimental)
Neuroprotective agents

A multidisciplinary approach involving neurologists, geneticists, therapists, and other specialists is often necessary for comprehensive management of pediatric ataxias.

Prognosis of Pediatric Ataxias

The prognosis for children with ataxia varies widely depending on the underlying cause:

Acute Ataxias: Often have a good prognosis with complete recovery, especially in cases of post-infectious cerebellitis or drug-induced ataxia.
Genetic Ataxias: Generally have a progressive course, but the rate of progression and severity can vary. Some forms may have periods of stability.
Metabolic Ataxias: Prognosis depends on the specific disorder and the effectiveness of available treatments. Early diagnosis and intervention can improve outcomes.
Structural Causes: Prognosis depends on the nature of the lesion and the success of interventions (e.g., tumor removal).

Factors influencing prognosis include:

Age of onset
Rate of progression
Presence of associated neurological deficits
Availability and effectiveness of specific treatments
Access to supportive care and rehabilitation services

Regular follow-up and monitoring are essential to assess disease progression and adjust management strategies. Genetic counseling may be recommended for families of children with hereditary ataxias.

Introduction to Pediatric Dystonias

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. Pediatric dystonias represent a complex group of disorders that can significantly impact a child's quality of life and development.

Key points:

Prevalence: Estimated at 2-50 per million for early-onset dystonias
Age of onset: Can occur from infancy to adolescence
Heterogeneous in etiology, presentation, and prognosis
Can be isolated or part of a complex neurological syndrome
Often progressive, but some forms may be static or even improve with age

Etiology of Pediatric Dystonias

The etiology of pediatric dystonias is diverse and can be categorized into several groups:

1. Genetic Causes:

DYT-TOR1A (DYT1): Autosomal dominant, early-onset generalized dystonia
DYT-THAP1 (DYT6): Autosomal dominant dystonia with cranio-cervical predominance
DYT-GCH1 (DYT5a): Autosomal dominant dopa-responsive dystonia
PRKRA (DYT16): Autosomal recessive dystonia-parkinsonism
ATP1A3: Rapid-onset dystonia-parkinsonism

2. Neurodegenerative Disorders:

Wilson's disease
Neurodegeneration with brain iron accumulation (NBIA)
Mitochondrial disorders
Lysosomal storage disorders

3. Acquired Causes:

Perinatal brain injury
Infections (e.g., encephalitis)
Autoimmune disorders
Toxins and medications
Stroke
Traumatic brain injury

4. Metabolic Disorders:

Glutaric aciduria type 1
Methylmalonic acidemia
Organic acidurias

5. Idiopathic:

In many cases, especially in focal dystonias, the cause remains unknown.

Classification of Pediatric Dystonias

Pediatric dystonias can be classified based on several factors:

1. Age of Onset:

Infancy (0-2 years)
Early childhood (3-12 years)
Adolescence (13-20 years)

2. Distribution:

Focal: Affects a single body region
Segmental: Involves two or more contiguous body regions
Multifocal: Involves two or more non-contiguous body regions
Generalized: Involves the trunk and at least two other body regions
Hemidystonia: Involves half of the body

3. Temporal Pattern:

Persistent: Consistent dystonia throughout the day
Action-specific: Occurs only during particular activities
Diurnal fluctuations: Varies in severity throughout the day
Paroxysmal: Sudden, self-limited episodes of dystonia

4. Associated Features:

Isolated dystonia: Dystonia is the only motor feature
Combined dystonia: Dystonia is combined with other movement disorders
Complex dystonia: Dystonia occurs in the context of other neurological or systemic manifestations

5. Etiology:

Primary (or idiopathic): No identifiable cause or structural abnormality
Secondary: Due to an identifiable cause (e.g., genetic, acquired)

Clinical Presentation of Pediatric Dystonias

The clinical presentation of pediatric dystonias can vary widely depending on the underlying cause, age of onset, and distribution of symptoms. Key features include:

General Characteristics:

Abnormal postures or twisting movements
Muscle contractions leading to repetitive movements or abnormal postures
Often exacerbated by voluntary action
May have a diurnal pattern or be triggered by specific activities

Common Presentations:

Cervical dystonia: Abnormal head and neck postures
Blepharospasm: Involuntary eye closure
Oromandibular dystonia: Affecting mouth, jaw, and tongue
Limb dystonia: Abnormal postures of arms or legs, often task-specific
Truncal dystonia: Involving the torso, may cause postural abnormalities

Age-Specific Presentations:

Infancy: Opisthotonus, torticollis, or hand dystonia
Early childhood: Gait disturbances, hand dystonia affecting writing or other tasks
Adolescence: Task-specific dystonias, such as writer's cramp

Associated Symptoms:

Pain or discomfort in affected areas
Tremor, often dystonic tremor
Parkinsonism in some forms (e.g., dopa-responsive dystonia)
Cognitive impairment in some complex dystonias
Speech and swallowing difficulties in cranial dystonias

Red Flags for Secondary Dystonias:

Sudden onset or rapid progression
Associated neurological symptoms (e.g., seizures, developmental delay)
Systemic symptoms suggesting metabolic or neurodegenerative disorders
History of perinatal complications or infections

Diagnosis of Pediatric Dystonias

Diagnosing pediatric dystonias requires a comprehensive approach, including:

1. Clinical Assessment:

Detailed history: Age of onset, progression, family history, perinatal history
Physical and neurological examination
Assessment of dystonia distribution and severity
Evaluation for associated neurological or systemic features

2. Neuroimaging:

Magnetic Resonance Imaging (MRI): To identify structural abnormalities or neurodegenerative changes
Functional neuroimaging (e.g., PET, SPECT): May be useful in some cases

3. Genetic Testing:

Single-gene testing for specific dystonia genes (e.g., TOR1A, THAP1)
Next-generation sequencing panels for dystonia and related disorders
Whole exome or genome sequencing in complex cases

4. Biochemical and Metabolic Studies:

Serum copper and ceruloplasmin for Wilson's disease
CSF neurotransmitter analysis for dopa-responsive dystonia
Urine organic acids and plasma amino acids for metabolic disorders

5. Electrophysiological Studies:

Electromyography (EMG): To confirm dystonia and rule out other movement disorders
Electroencephalography (EEG): If seizures are suspected

6. Therapeutic Trials:

Levodopa trial for dopa-responsive dystonia
Trihexyphenidyl for isolated dystonia

7. Ophthalmological Examination:

Slit-lamp examination for Kayser-Fleischer rings in Wilson's disease
Fundoscopy for retinal abnormalities in some neurodegenerative disorders

Differential Diagnosis:

It's important to consider other movement disorders and neurological conditions, including:

Tics and Tourette syndrome
Chorea
Myoclonus
Paroxysmal dyskinesias
Functional (psychogenic) movement disorders

Management of Pediatric Dystonias

Management of pediatric dystonias is often complex and requires a multidisciplinary approach. The treatment strategy depends on the underlying cause, distribution, and severity of symptoms.

1. Pharmacological Interventions:

Oral medications:
- Anticholinergics (e.g., trihexyphenidyl): First-line for many childhood-onset dystonias
- Dopaminergic drugs (e.g., levodopa): For dopa-responsive dystonia
- Baclofen: Particularly useful for dystonia with spasticity
- Benzodiazepines: For dystonia with associated anxiety or sleep disturbances
Botulinum toxin injections: For focal or segmental dystonias
Intrathecal baclofen: For severe generalized dystonia

2. Surgical Interventions:

Deep Brain Stimulation (DBS): Particularly effective for DYT1 dystonia and some other genetic forms
Selective peripheral denervation: For cervical dystonia refractory to other treatments
Intrathecal baclofen pump implantation

3. Physical and Occupational Therapy:

Stretching exercises to maintain range of motion
Strengthening exercises for antagonist muscles
Gait training and balance exercises
Task-specific training for focal dystonias

4. Assistive Devices and Orthotics:

Customized seating systems
Mobility aids
Writing aids for hand dystonia
Orthoses to maintain posture and prevent contractures

5. Speech and Language Therapy:

For dystonias affecting speech and swallowing
Alternative and augmentative communication devices when needed

6. Psychological Support:

Cognitive-behavioral therapy
Family counseling
Support groups

7. Education and Vocational Training:

Individualized Education Programs (IEPs)
Adaptations in school and work environments

8. Treatment of Underlying Causes:

Specific treatments for identifiable causes (e.g., chelation therapy for Wilson's disease)
Management of associated neurological or systemic conditions

Prognosis of Pediatric Dystonias

The prognosis of pediatric dystonias varies widely depending on the underlying cause, age of onset, and distribution of symptoms. Key factors influencing prognosis include:

Factors Affecting Prognosis:

Etiology: Primary vs. secondary dystonias
Age of onset: Earlier onset often associated with more severe course
Distribution: Focal dystonias generally have better outcomes than generalized forms
Presence of associated neurological or systemic features
Timely diagnosis and initiation of appropriate treatment
Response to initial therapeutic interventions

Prognosis by Dystonia Type:

DYT1 dystonia: Often responds well to DBS, but severity can vary
Dopa-responsive dystonia: Excellent prognosis with levodopa treatment
Secondary dystonias: Prognosis depends on underlying cause and extent of brain injury
Paroxysmal dystonias: Often good response to medication, with some forms resolving with age
Focal dystonias: Generally better prognosis, may remain focal or expand over time
Complex dystonias associated with neurodegenerative disorders: Often progressive with guarded prognosis

Long-term Outcomes:

Motor function: Ranges from mild impairment to severe disability
Pain: Chronic pain can significantly impact quality of life
Education and employment: Many patients can attend mainstream schools and gain employment with appropriate support
Social integration: May be challenging, especially in severe cases
Mental health: Increased risk of anxiety and depression

Potential Complications:

Musculoskeletal deformities and contractures
Chronic pain syndromes
Nutritional deficiencies in severe oromandibular dystonia
Respiratory complications in severe generalized dystonia
Side effects from long-term medication use

Prognostic Considerations:

Some forms of dystonia may plateau or even improve with age
Early intervention and appropriate management can significantly improve outcomes
Advances in genetic testing and targeted therapies may improve prognosis for some forms of dystonia
Regular follow-up and adjustments to treatment plans are essential for optimal outcomes

It's important to note that the prognosis of pediatric dystonias can be highly individual, and providing families with realistic expectations while maintaining hope is crucial. Regular reassessment and a flexible, multidisciplinary approach to management can help optimize outcomes for children with dystonia.

Chorea, Athetosis in Children

Question: What is chorea?
Answer: Chorea is a movement disorder characterized by brief, irregular, and unpredictable muscle contractions that appear to flow from one body part to another.
Question: What is athetosis?
Answer: Athetosis is a slow, writhing, continuous, involuntary movement of the hands, arms, legs, and neck.
Question: Which part of the brain is primarily affected in chorea?
Answer: The basal ganglia, particularly the striatum (caudate nucleus and putamen), are primarily affected in chorea.
Question: What is the most common cause of acute chorea in children?
Answer: Sydenham's chorea, associated with rheumatic fever, is the most common cause of acute chorea in children.
Question: How is Huntington's disease inherited?
Answer: Huntington's disease is inherited in an autosomal dominant pattern.
Question: What is the genetic defect in Huntington's disease?
Answer: Huntington's disease is caused by an expanded CAG trinucleotide repeat in the huntingtin gene on chromosome 4.
Question: Which neurotransmitter system is primarily affected in chorea?
Answer: The dopamine system is primarily affected in chorea.
Question: What is the characteristic feature of chorea gravidarum?
Answer: Chorea gravidarum is chorea occurring during pregnancy, often in women with a history of Sydenham's chorea.
Question: Which medication is commonly used to treat chorea in children?
Answer: Haloperidol, a dopamine receptor antagonist, is commonly used to treat chorea in children.
Question: What is Sydenham's chorea also known as?
Answer: Sydenham's chorea is also known as St. Vitus' dance.
Question: How long does Sydenham's chorea typically last?
Answer: Sydenham's chorea typically lasts 2-6 months, but can persist for up to 2 years.
Question: What is the underlying cause of Sydenham's chorea?
Answer: Sydenham's chorea is caused by an autoimmune response to Group A beta-hemolytic streptococcal infection.
Question: Which diagnostic test can help confirm a recent streptococcal infection in a child with suspected Sydenham's chorea?
Answer: Anti-streptolysin O (ASO) titer can help confirm a recent streptococcal infection.
Question: What is the most common imaging finding in children with Sydenham's chorea?
Answer: The most common imaging finding is reversible striatal hyperintensities on T2-weighted MRI.
Question: Which medication is used for prophylaxis against recurrent rheumatic fever in children with Sydenham's chorea?
Answer: Penicillin is used for prophylaxis against recurrent rheumatic fever.
Question: What is kernicterus?
Answer: Kernicterus is a neurological condition caused by severe hyperbilirubinemia in newborns, which can lead to athetoid cerebral palsy.
Question: Which genetic disorder is associated with chorea-acanthocytosis?
Answer: Mutations in the VPS13A gene are associated with chorea-acanthocytosis.
Question: What is the characteristic feature of benign hereditary chorea?
Answer: Benign hereditary chorea is characterized by early-onset, non-progressive chorea without cognitive decline.
Question: Which neurodegenerative disorder is characterized by chorea, dementia, and psychiatric symptoms?
Answer: Huntington's disease is characterized by chorea, dementia, and psychiatric symptoms.
Question: What is the typical age of onset for juvenile Huntington's disease?
Answer: Juvenile Huntington's disease typically has an onset before 20 years of age.
Question: Which autoimmune condition can cause chorea in children?
Answer: Systemic lupus erythematosus (SLE) can cause chorea in children.
Question: What is the most common metabolic cause of chorea in children?
Answer: Hyperthyroidism is the most common metabolic cause of chorea in children.
Question: Which medication used in the treatment of Parkinson's disease can cause chorea as a side effect?
Answer: Levodopa can cause chorea as a side effect in some patients.
Question: What is Lesch-Nyhan syndrome?
Answer: Lesch-Nyhan syndrome is an X-linked recessive disorder characterized by hyperuricemia, cognitive impairment, and self-mutilating behavior, often with choreoathetoid movements.
Question: Which neuroimaging technique is most useful for evaluating basal ganglia metabolism in chorea?
Answer: Positron emission tomography (PET) is most useful for evaluating basal ganglia metabolism in chorea.
Question: What is the primary treatment for chorea associated with hyperthyroidism?
Answer: The primary treatment is managing the underlying thyroid disorder to achieve a euthyroid state.
Question: Which vitamin deficiency can cause chorea in children?
Answer: Vitamin B12 deficiency can cause chorea in children.
Question: What is chorea mollis?
Answer: Chorea mollis is a severe form of Sydenham's chorea characterized by profound hypotonia and inability to maintain posture.
Question: Which genetic test is used to confirm the diagnosis of Huntington's disease?
Answer: The CAG repeat expansion test in the HTT gene is used to confirm the diagnosis of Huntington's disease.
Question: What is the role of carbamazepine in treating chorea?
Answer: Carbamazepine can be effective in treating some forms of paroxysmal kinesigenic choreoathetosis.

Myoclonus in Children

Question: What is myoclonus?
Answer: Myoclonus is a brief, shock-like, involuntary contraction of a muscle or group of muscles.
Question: How does myoclonus differ from tics?
Answer: Myoclonus is typically faster and less suppressible than tics, and doesn't have a premonitory urge.
Question: What is the most common type of physiological myoclonus?
Answer: Hiccups are the most common type of physiological myoclonus.
Question: What is nocturnal myoclonus?
Answer: Nocturnal myoclonus, also known as sleep myoclonus, refers to involuntary muscle jerks that occur during sleep or while falling asleep.
Question: Which part of the nervous system is involved in cortical myoclonus?
Answer: Cortical myoclonus originates from the cerebral cortex.
Question: What is the difference between positive and negative myoclonus?
Answer: Positive myoclonus involves sudden muscle contractions, while negative myoclonus involves brief lapses of muscle tone.
Question: Which neurotransmitter is most commonly associated with myoclonus?
Answer: Serotonin dysfunction is most commonly associated with myoclonus.
Question: What is juvenile myoclonic epilepsy?
Answer: Juvenile myoclonic epilepsy is a generalized epilepsy syndrome characterized by myoclonic jerks, typically occurring in the morning.
Question: At what age does juvenile myoclonic epilepsy typically begin?
Answer: Juvenile myoclonic epilepsy typically begins between 12 and 18 years of age.
Question: What is the most common trigger for myoclonic seizures in juvenile myoclonic epilepsy?
Answer: Sleep deprivation is the most common trigger for myoclonic seizures in juvenile myoclonic epilepsy.
Question: Which medication is considered first-line treatment for juvenile myoclonic epilepsy?
Answer: Valproic acid is considered the first-line treatment for juvenile myoclonic epilepsy.
Question: What is Lance-Adams syndrome?
Answer: Lance-Adams syndrome is a form of post-hypoxic myoclonus that occurs after cardiopulmonary resuscitation.
Question: Which genetic disorder is associated with progressive myoclonus epilepsy?
Answer: Unverricht-Lundborg disease, caused by mutations in the CSTB gene, is associated with progressive myoclonus epilepsy.
Question: What is opsoclonus-myoclonus syndrome?
Answer: Opsoclonus-myoclonus syndrome is characterized by rapid, multi-directional eye movements (opsoclonus), myoclonus, and ataxia, often associated with neuroblastoma in children.
Question: Which neurotransmitter system is targeted by most antimyoclonic drugs?
Answer: Most antimyoclonic drugs target the GABAergic system to enhance inhibitory neurotransmission.
Question: What is palatal myoclonus?
Answer: Palatal myoclonus is a rare movement disorder characterized by rhythmic contractions of the soft palate muscles.
Question: Which imaging technique is most useful for detecting structural causes of myoclonus?
Answer: Magnetic Resonance Imaging (MRI) is most useful for detecting structural causes of myoclonus.
Question: What is the role of electroencephalography (EEG) in evaluating myoclonus?
Answer: EEG can help differentiate between cortical and subcortical myoclonus and identify epileptiform discharges associated with myoclonic seizures.
Question: Which metabolic disorder can present with myoclonus in children?
Answer: Maple syrup urine disease can present with myoclonus in children during metabolic decompensation.
Question: What is myoclonus-dystonia syndrome?
Answer: Myoclonus-dystonia syndrome is a genetic disorder characterized by a combination of myoclonic jerks and dystonic movements, typically affecting the upper body.
Question: Which medication used for epilepsy can paradoxically worsen myoclonic seizures?
Answer: Carbamazepine can paradoxically worsen myoclonic seizures, especially in patients with juvenile myoclonic epilepsy.
Question: What is the characteristic EEG finding in juvenile myoclonic epilepsy?
Answer: Generalized polyspike-and-wave discharges are the characteristic EEG finding in juvenile myoclonic epilepsy.
Question: Which vitamin deficiency can cause myoclonus?
Answer: Vitamin E deficiency can cause myoclonus, particularly in children with fat malabsorption syndromes.
Question: What is Baltic myoclonus?
Answer: Baltic myoclonus is another name for Unverricht-Lundborg disease, a form of progressive myoclonus epilepsy.
Question: Which neurodegenerative disorder is characterized by myoclonus and cherry-red spots on ophthalmologic examination?
Answer: Tay-Sachs disease is characterized by myoclonus and cherry-red spots on ophthalmologic examination.
Question: What is the role of levetiracetam in treating myoclonus?
Answer: Levetiracetam is effective in treating various forms of myoclonus, including cortical myoclonus and juvenile myoclonic epilepsy.
Question: Which autoimmune condition can cause opsoclonus-myoclonus syndrome in children?
Answer: Neuroblastoma-associated paraneoplastic syndrome can cause opsoclonus-myoclonus syndrome in children.
Question: What is the primary treatment for opsoclonus-myoclonus syndrome?
Answer: The primary treatment includes immunotherapy (such as corticosteroids, intravenous immunoglobulin, or rituximab) and treatment of the underlying cause if identified.
Question: Which genetic test is used to confirm the diagnosis of myoclonus-dystonia syndrome?
Answer: Genetic testing for mutations in the SGCE gene is used to confirm the diagnosis of myoclonus-dystonia syndrome.
Question: What is the role of botulinum toxin injections in treating myoclonus?
Answer: Botulinum toxin injections can be useful in treating focal forms of myoclonus, such as palatal myoclonus.

Tremor in Children

Question: What is tremor?
Answer: Tremor is an involuntary, rhythmic oscillatory movement of a body part.
Question: How is tremor classified based on its occurrence?
Answer: Tremor is classified as rest tremor (occurring when the affected body part is relaxed) or action tremor (occurring during voluntary movement).
Question: What is the most common type of tremor in children?
Answer: Enhanced physiological tremor is the most common type of tremor in children.
Question: What is essential tremor?
Answer: Essential tremor is a progressive, often inherited, action tremor that typically affects the hands, head, and voice.
Question: At what age does essential tremor typically begin in children?
Answer: Essential tremor in children typically begins around 6-7 years of age but can occur earlier.
Question: Which part of the brain is primarily involved in essential tremor?
Answer: The cerebellum and its connections are primarily involved in essential tremor.
Question: What is the characteristic feature of parkinsonian tremor?
Answer: Parkinsonian tremor is typically a rest tremor with a frequency of 4-6 Hz, often described as "pill-rolling."
Question: Which medication is commonly used as first-line treatment for essential tremor in children?
Answer: Propranolol, a beta-blocker, is commonly used as first-line treatment for essential tremor in children.
Question: What is cerebellar tremor?
Answer: Cerebellar tremor is an intention tremor that becomes more pronounced as the affected body part approaches its target.
Question: Which vitamin deficiency can cause tremor in children?
Answer: Vitamin B12 deficiency can cause tremor in children, along with other neurological symptoms.
Question: What is orthostatic tremor?
Answer: Orthostatic tremor is a high-frequency tremor that occurs in the legs when standing still and is relieved by walking or sitting.
Question: Which endocrine disorder commonly causes tremor in children?
Answer: Hyperthyroidism commonly causes tremor in children, typically presenting as a fine, rapid tremor.
Question: What is the role of deep brain stimulation in treating tremor?
Answer: Deep brain stimulation of the ventral intermediate nucleus of the thalamus can be effective in treating severe, medication-resistant essential tremor.
Question: What is psychogenic tremor?
Answer: Psychogenic tremor is a functional tremor that is part of a conversion disorder, often with variable frequency and amplitude.
Question: Which genetic condition is associated with intention tremor and ataxia in children?
Answer: Friedreich's ataxia is associated with intention tremor and ataxia in children.
Question: What is Holmes tremor?
Answer: Holmes tremor is a low-frequency, combined resting and intention tremor that results from lesions in the brainstem, cerebellum, or thalamus.
Question: Which medication used for attention deficit hyperactivity disorder (ADHD) can cause tremor as a side effect?
Answer: Stimulant medications like methylphenidate can cause tremor as a side effect in children with ADHD.
Question: What is the role of primidone in treating tremor?
Answer: Primidone is an effective second-line medication for essential tremor, particularly when propranolol is ineffective or contraindicated.
Question: Which neuroimaging technique is most useful for evaluating cerebellar function in tremor?
Answer: Functional MRI (fMRI) is most useful for evaluating cerebellar function in tremor.
Question: What is writing tremor?
Answer: Writing tremor is a task-specific tremor that occurs primarily or exclusively during writing.
Question: Which autoimmune condition can cause tremor in children?
Answer: Multiple sclerosis can cause tremor in children, typically presenting as an intention tremor.
Question: What is the characteristic frequency range of essential tremor?
Answer: Essential tremor typically occurs at a frequency of 4-12 Hz.
Question: Which toxin exposure can cause tremor in children?
Answer: Mercury poisoning can cause tremor in children, along with other neurological symptoms.
Question: What is the role of botulinum toxin injections in treating tremor?
Answer: Botulinum toxin injections can be useful in treating focal forms of tremor, such as head or voice tremor.
Question: Which genetic test is used to confirm the diagnosis of fragile X-associated tremor/ataxia syndrome?
Answer: FMR1 gene testing is used to confirm the diagnosis of fragile X-associated tremor/ataxia syndrome.
Question: What is Wilson's disease and how does it relate to tremor?
Answer: Wilson's disease is a genetic disorder of copper metabolism that can cause tremor, along with other neurological and hepatic symptoms.
Question: How does alcohol typically affect essential tremor?
Answer: Alcohol typically temporarily reduces the amplitude of essential tremor.

Pediatric Ataxias

Question: What is ataxia?
Answer: Ataxia is a neurological sign characterized by impaired coordination of voluntary movements, typically due to dysfunction of the cerebellum or its connections.
Question: What are the three main types of ataxia based on clinical presentation?
Answer: The three main types are cerebellar ataxia, sensory ataxia, and vestibular ataxia.
Question: Which part of the cerebellum is primarily responsible for controlling gait and balance?
Answer: The vermis of the cerebellum is primarily responsible for controlling gait and balance.
Question: What is Friedreich's ataxia?
Answer: Friedreich's ataxia is an autosomal recessive neurodegenerative disorder characterized by progressive ataxia, absent lower limb reflexes, and cardiomyopathy.
Question: What is the genetic defect in Friedreich's ataxia?
Answer: Friedreich's ataxia is caused by a GAA trinucleotide repeat expansion in the FXN gene, which encodes the protein frataxin.
Question: What is ataxia-telangiectasia?
Answer: Ataxia-telangiectasia is an autosomal recessive disorder characterized by progressive cerebellar ataxia, oculocutaneous telangiectasias, immunodeficiency, and increased cancer risk.
Question: Which gene is mutated in ataxia-telangiectasia?
Answer: The ATM (Ataxia Telangiectasia Mutated) gene is mutated in ataxia-telangiectasia.
Question: What is the most common cause of acute cerebellar ataxia in children?
Answer: Acute post-infectious cerebellar ataxia, often following a viral infection, is the most common cause of acute cerebellar ataxia in children.
Question: Which vitamin deficiency can cause ataxia in children?
Answer: Vitamin E deficiency can cause ataxia in children, particularly in those with fat malabsorption syndromes.
Question: What is Joubert syndrome?
Answer: Joubert syndrome is a genetic disorder characterized by cerebellar vermis hypoplasia, ataxia, and a distinctive brainstem malformation called the "molar tooth sign" on MRI.
Question: What is the "molar tooth sign" in Joubert syndrome?
Answer: The "molar tooth sign" is a distinctive MRI finding in Joubert syndrome, characterized by a deep interpeduncular fossa and thick, elongated superior cerebellar peduncles.
Question: Which metabolic disorder can present with episodic ataxia in children?
Answer: Maple syrup urine disease can present with episodic ataxia in children during metabolic decompensation.
Question: What are the clinical features of spinocerebellar ataxia type 1 (SCA1)?
Answer: SCA1 is characterized by progressive ataxia, dysarthria, and eventually bulbar dysfunction and cognitive impairment.
Question: Which medication is used to treat episodic ataxia type 2?
Answer: Acetazolamide is commonly used to treat episodic ataxia type 2.
Question: What is Dandy-Walker malformation?
Answer: Dandy-Walker malformation is a congenital brain malformation characterized by hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa.
Question: What is Refsum disease?
Answer: Refsum disease is a rare peroxisomal disorder characterized by ataxia, retinitis pigmentosa, anosmia, and elevated phytanic acid levels.
Question: Which neuroimaging technique is most useful for evaluating cerebellar atrophy in pediatric ataxias?
Answer: Magnetic Resonance Imaging (MRI) is most useful for evaluating cerebellar atrophy in pediatric ataxias.
Question: What is the role of genetic testing in diagnosing pediatric ataxias?
Answer: Genetic testing can confirm diagnoses of hereditary ataxias, identify specific mutations, and guide genetic counseling and management.
Question: What is olivopontocerebellar atrophy?
Answer: Olivopontocerebellar atrophy is a neurodegenerative disorder characterized by progressive degeneration of the cerebellum, pons, and inferior olives, leading to ataxia and other neurological symptoms.
Question: Which autoimmune condition can cause ataxia in children?
Answer: Multiple sclerosis can cause ataxia in children, typically presenting as cerebellar ataxia.
Question: What is the characteristic eye movement abnormality in Friedreich's ataxia?
Answer: Square wave jerks, which are small, horizontal saccadic intrusions during fixation, are characteristic of Friedreich's ataxia.
Question: What is spinocerebellar ataxia with axonal neuropathy (SCAN1)?
Answer: SCAN1 is a rare autosomal recessive disorder characterized by ataxia, peripheral neuropathy, and cerebellar atrophy, caused by mutations in the TDP1 gene.
Question: Which toxin exposure can cause ataxia in children?
Answer: Mercury poisoning can cause ataxia in children, along with other neurological symptoms.
Question: What is the role of physical therapy in managing pediatric ataxias?
Answer: Physical therapy plays a crucial role in maintaining mobility, improving balance and coordination, and preventing complications in children with ataxias.
Question: What is ataxia with vitamin E deficiency (AVED)?
Answer: AVED is an autosomal recessive disorder caused by mutations in the TTPA gene, leading to impaired vitamin E transport and a clinical picture similar to Friedreich's ataxia.
Question: Which genetic test is used to confirm the diagnosis of Friedreich's ataxia?
Answer: Genetic testing for GAA repeat expansion in the FXN gene is used to confirm the diagnosis of Friedreich's ataxia.
Question: What is the role of occupational therapy in managing pediatric ataxias?
Answer: Occupational therapy helps children with ataxias develop strategies to perform daily activities, use adaptive equipment, and maintain independence.
Question: What is cerebellar cognitive affective syndrome?
Answer: Cerebellar cognitive affective syndrome is a constellation of cognitive and behavioral abnormalities associated with cerebellar dysfunction, including executive function deficits, visuospatial difficulties, language problems, and affective dysregulation.
Question: What is the prognosis for children with Friedreich's ataxia?
Answer: The prognosis for Friedreich's ataxia is generally poor, with progressive neurological deterioration and cardiac complications leading to reduced life expectancy.

Pediatric Dystonias

Question: What is dystonia?
Answer: Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both.
Question: How are dystonias classified based on body distribution?
Answer: Dystonias are classified as focal (affecting a single body part), segmental (affecting adjacent body parts), multifocal (affecting multiple non-adjacent body parts), hemidystonia (affecting one side of the body), or generalized (affecting multiple body parts).
Question: What is the most common type of primary dystonia in children?
Answer: DYT1 dystonia, caused by a mutation in the TOR1A gene, is the most common type of primary dystonia in children.
Question: At what age does DYT1 dystonia typically begin?
Answer: DYT1 dystonia typically begins in late childhood or early adolescence, with an average age of onset around 12 years.
Question: What is dopa-responsive dystonia?
Answer: Dopa-responsive dystonia, also known as Segawa syndrome, is a genetic disorder characterized by childhood-onset dystonia that dramatically improves with levodopa treatment.
Question: Which gene is most commonly mutated in dopa-responsive dystonia?
Answer: The GCH1 gene, which encodes GTP cyclohydrolase 1, is most commonly mutated in dopa-responsive dystonia.
Question: What is the characteristic diurnal fluctuation seen in dopa-responsive dystonia?
Answer: Symptoms in dopa-responsive dystonia typically worsen throughout the day and improve after sleep.
Question: What is cerebral palsy?
Answer: Cerebral palsy is a group of permanent disorders affecting movement and posture, caused by non-progressive disturbances in the developing fetal or infant brain.
Question: Which type of cerebral palsy is most commonly associated with dystonia?
Answer: Dyskinetic cerebral palsy, which includes both dystonic and choreoathetoid forms, is most commonly associated with dystonia.
Question: What is tardive dystonia?
Answer: Tardive dystonia is a form of dystonia that develops as a side effect of long-term use of dopamine receptor blocking agents, such as antipsychotic medications.
Question: What is writer's cramp?
Answer: Writer's cramp is a task-specific focal dystonia affecting the muscles of the hand and forearm, causing abnormal postures and movements during writing.
Question: Which neuroimaging technique is most useful for detecting structural causes of dystonia in children?
Answer: Magnetic Resonance Imaging (MRI) is most useful for detecting structural causes of dystonia in children.
Question: What is the role of genetic testing in diagnosing pediatric dystonias?
Answer: Genetic testing can confirm diagnoses of hereditary dystonias, identify specific mutations, and guide genetic counseling and management.
Question: What is the most common initial treatment for focal dystonia in children?
Answer: Botulinum toxin injections are the most common initial treatment for focal dystonia in children.
Question: Which medication is the first-line treatment for dopa-responsive dystonia?
Answer: Levodopa is the first-line treatment for dopa-responsive dystonia.
Question: What is deep brain stimulation (DBS) in the context of dystonia treatment?
Answer: Deep brain stimulation is a surgical treatment involving the implantation of electrodes in specific brain areas, typically the globus pallidus interna, to deliver electrical stimulation and alleviate dystonic symptoms.
Question: What is myoclonus-dystonia syndrome?
Answer: Myoclonus-dystonia syndrome is a genetic disorder characterized by a combination of myoclonic jerks and dystonic movements, typically affecting the upper body.
Question: Which gene is most commonly mutated in myoclonus-dystonia syndrome?
Answer: The SGCE gene, which encodes epsilon-sarcoglycan, is most commonly mutated in myoclonus-dystonia syndrome.
Question: What is rapid-onset dystonia-parkinsonism?
Answer: Rapid-onset dystonia-parkinsonism is a rare genetic disorder characterized by the abrupt onset of dystonia and parkinsonism over a period of hours to weeks.
Question: Which metabolic disorder can present with dystonia in children?
Answer: Wilson's disease, a disorder of copper metabolism, can present with dystonia in children.
Question: What is the role of physical therapy in managing pediatric dystonias?
Answer: Physical therapy helps maintain range of motion, prevent contractures, improve posture and balance, and teach compensatory strategies in children with dystonia.
Question: What is sensory trick or geste antagoniste in dystonia?
Answer: A sensory trick or geste antagoniste is a voluntary maneuver that temporarily reduces the severity of dystonic postures or movements.
Question: What is X-linked dystonia-parkinsonism (Lubag)?
Answer: X-linked dystonia-parkinsonism is a rare genetic disorder characterized by adult-onset dystonia that progresses to parkinsonism, primarily affecting Filipino men.
Question: Which neurotransmitter system is primarily targeted in the pharmacological treatment of dystonia?
Answer: The dopaminergic system is primarily targeted in the pharmacological treatment of dystonia.
Question: What is status dystonicus?
Answer: Status dystonicus, also known as dystonic storm, is a life-threatening emergency characterized by severe, generalized, and often continuous dystonic spasms.
Question: What is the role of occupational therapy in managing pediatric dystonias?
Answer: Occupational therapy helps children with dystonia develop strategies to perform daily activities, use adaptive equipment, and maintain independence.
Question: What is focal task-specific dystonia?
Answer: Focal task-specific dystonia is a form of dystonia that occurs only during the performance of a specific, skilled task, such as writing or playing a musical instrument.
Question: Which imaging finding is characteristic of pantothenate kinase-associated neurodegeneration (PKAN), a cause of dystonia?
Answer: The "eye-of-the-tiger" sign on T2-weighted MRI, characterized by hypointensity of the globus pallidus with a central hyperintensity, is characteristic of PKAN.