What is the management for an 11-year-old female with a history of Chiari malformation (CM) presenting to the emergency room (ER) after a witnessed syncopal episode with seizure-like activity?

Management of Syncope with Seizure-like Activity in a Child with Chiari Malformation

Initial Assessment and Stabilization

For an 11-year-old female with Chiari malformation presenting after witnessed syncope with seizure-like activity, immediate neuroimaging with MRI of the brain and craniocervical junction is essential to evaluate for worsening of the Chiari malformation and to rule out other neurological causes.

The initial management should follow this algorithm:

1. Immediate stabilization:

   • Ensure airway, breathing, and circulation are stable
   • Place in recovery position if still postictal
   • Monitor vital signs including orthostatic measurements

2. Focused history (from witnesses and patient):

   • Duration of loss of consciousness
   • Presence of prodromal symptoms (lightheadedness, nausea, visual changes)
   • Description of seizure-like activity (duration, type of movements)
   • Post-event symptoms (confusion, headache, focal deficits)
   • Recent headaches, especially those worsened by Valsalva maneuvers 1

3. Neurological examination:

   • Complete neurological assessment including cranial nerves
   • Look for papilledema and other signs of increased intracranial pressure
   • Assess for focal deficits that may indicate brainstem compression

Diagnostic Evaluation

The diagnostic workup should include:

1. Neuroimaging:

   • MRI of the brain with sagittal T2-weighted sequence of the craniocervical junction 1
   • Consider optional phase-contrast CSF flow study at the craniocervical junction 1
   • This is critical to assess for worsening of tonsillar herniation, syringomyelia, or hydrocephalus

2. Cardiac evaluation:

   • 12-lead ECG to rule out cardiac causes of syncope
   • Consider 24-hour Holter monitoring if initial ECG is normal but cardiac cause is suspected 1

3. EEG:

   • Indicated when epilepsy is suspected as the cause of seizure-like activity
   • Note that brief seizure-like activity can occur during syncope and does not necessarily indicate epilepsy 1

4. Laboratory tests:

   • Complete blood count
   • Electrolytes, glucose
   • Consider toxicology screen if indicated

Differential Diagnosis

The differential diagnosis should consider:

1. Chiari malformation-related syncope:

   • Compression of brainstem structures 1, 2
   • Altered CSF dynamics leading to increased intracranial pressure 3
   • Postural orthostatic tachycardia syndrome (POTS) associated with Chiari malformation 2

2. Neurally mediated syncope:

   • Most common cause of syncope in pediatric population (75% of cases) 1
   • Can present with brief seizure-like activity (convulsive syncope) 1

3. Epileptic seizure:

   • Chiari malformations have been associated with seizures in some cases 4
   • Requires EEG for diagnosis

4. Cardiac syncope:

   • Less common but more serious
   • Requires ECG and cardiac evaluation

Management Plan

Based on the diagnostic findings:

1. If imaging shows worsening of Chiari malformation:

   • Urgent neurosurgical consultation for potential decompression 5, 2
   • Surgical decompression has been shown to resolve syncope in patients with Chiari malformation 5, 2

2. If neurally mediated syncope is diagnosed:

   • Education about triggers and prodromal symptoms
   • Increased fluid and salt intake
   • Avoidance of prolonged standing
   • Consider compression stockings
   • Medications rarely needed in pediatric population 1

3. If seizures are confirmed:

   • Neurology consultation
   • Appropriate antiepileptic medication based on seizure type 6
   • Regular follow-up with neurology

4. If orthostatic intolerance is identified:

   • Consider tilt-table testing
   • Management of POTS if diagnosed 1

Follow-up and Monitoring

1. Neurosurgical follow-up:

   • Regular monitoring of Chiari malformation with serial imaging
   • Assessment for development of syringomyelia

2. Neurological follow-up:

   • Monitor for recurrent syncope or seizures
   • Assess for progression of symptoms related to Chiari malformation

3. Education for patient and family:

   • Recognition of warning signs requiring immediate medical attention
   • Avoidance of activities that increase intracranial pressure (heavy lifting, straining)
   • Safety precautions to prevent injury during potential syncope episodes

Important Considerations

• Syncope with seizure-like activity can be misdiagnosed as epilepsy. Brief tonic-clonic movements can occur during syncope due to cerebral hypoperfusion and do not necessarily indicate epilepsy 1.

• Chiari malformation can cause syncope through multiple mechanisms, including brainstem compression, altered CSF dynamics, and autonomic dysfunction 5, 2.

• The combination of Chiari malformation and syncope with seizure-like activity requires thorough evaluation to determine if the syncope is directly related to the Chiari malformation or represents a separate condition.

• Surgical decompression should be considered if the syncope is determined to be related to the Chiari malformation, as it has been shown to resolve symptoms in reported cases 5, 2.