What is the management approach for Alternating Hemiplegia of Childhood (AHC)?

Management of Alternating Hemiplegia of Childhood (AHC)

Flunarizine is the first-line treatment for Alternating Hemiplegia of Childhood, with evidence of efficacy in reducing frequency and severity of hemiplegic episodes based on extensive open-label experience across hundreds of patients. 1

Disease Overview and Diagnostic Approach

Alternating Hemiplegia of Childhood is a rare and severe neurological disorder characterized by:

• Recurrent episodes of hemiplegia affecting either side of the body
• Onset typically in infancy (before 18 months of age)
• Paroxysmal eye movements (often the earliest symptom, appearing in first 3 months in 83% of patients) 2
• Other paroxysmal events including seizures, dystonia, tonic episodes, and autonomic dysfunction
• Primarily caused by de novo mutations in the ATP1A3 gene (found in approximately 80% of cases) 3

Management Framework

Acute Episode Management

1. Induce sleep immediately

   • Sleep completely or temporarily aborts episodes in all patients 2
   • Encourage rapid sleep onset when attacks begin

2. Benzodiazepines for acute management

   • Can help abort ongoing hemiplegic episodes 1
   • Useful for managing associated dystonia during attacks

Preventive Treatment Options

1. Calcium Channel Blockers

   • Flunarizine (5-10 mg daily): First-line therapy
     • Most widely used with best documented efficacy 1, 4
     • Reduces frequency and severity of hemiplegic episodes
     • Based on extensive open-label experience in hundreds of patients

2. Alternative or Adjunctive Medications (if flunarizine is ineffective or unavailable):

   • Topiramate: May reduce frequency of episodes 1
   • Aripiprazole: Case reports show reduction in frequency, duration, and severity of hemiplegic episodes 5
   • Acetazolamide: May help reduce attack frequency 1
   • Memantine or amantadine: NMDA receptor antagonists with some reported benefit 1
   • Benzodiazepines: For both acute and prophylactic use

3. Dietary Approaches

   • Ketogenic diet: May reduce frequency of episodes in some patients 1
   • Triheptanoin: Has shown some benefit in case reports 1

Management of Comorbidities

1. Epilepsy (present in approximately 41% of patients) 2

   • Standard antiepileptic drugs based on seizure type 1, 4
   • Distinguish between hemiplegic episodes and true seizures

2. Cognitive and Behavioral Issues (present in 100% of patients) 2

   • Formal neuropsychological evaluation to determine cognitive dysfunction etiology 6
   • Appropriate educational accommodations based on cognitive assessment
   • Management of ADHD symptoms and behavioral difficulties

3. Movement Disorders

   • Treatment of dystonia, ataxia (present in 96% of patients) 2
   • Physical therapy for motor impairments

Practical Management Tips

1. Trigger Avoidance

   • Identify and avoid individual triggers (common triggers include stress, excitement, temperature changes, bright lights) 4
   • Maintain regular sleep patterns

2. Documentation

   • Maintain a detailed diary of paroxysmal events, including:
     • Duration and characteristics of episodes
     • Potential triggers
     • Response to interventions 1

3. Emergency Protocol

   • Develop a written emergency plan for caregivers and schools
   • Include instructions for benzodiazepine administration and sleep induction

4. Multidisciplinary Care

   • Coordinate care between neurology, psychiatry, physical therapy, and educational services 1, 3
   • Regular follow-up with specialists experienced in AHC management

Monitoring and Follow-up

• Regular assessment of medication efficacy and side effects
• Monitor for developmental progress and educational needs
• Adjust treatment plan based on changing symptoms and developmental stage

Important Caveats

• Treatment response is highly variable between patients
• Empiric pharmacologic approaches offer limited benefit in many patients and cause adverse effects in approximately 20% 2
• No true disease-modifying therapy currently exists 1
• Treatment evidence is largely based on case reports and small case series rather than controlled trials

The management of AHC remains challenging due to its rarity and variable presentation. While flunarizine has the strongest evidence base, treatment should be tailored based on individual response and supplemented with comprehensive management of comorbidities and trigger avoidance strategies.