How do you differentiate and manage a Tet spell (Tetralogy of Fallot spell) from a seizure in a pediatric patient?

Differentiating and Managing Tet Spells from Seizures in Pediatric Patients

Tet spells (hypercyanotic episodes in Tetralogy of Fallot) require immediate administration of morphine (0.1 mg/kg IV/IM) and knee-chest positioning, while seizures require supportive care and positioning on the side to prevent aspiration.

Key Clinical Features for Differentiation

Tet Spells

• Characteristic presentation:
  • Sudden onset of deep cyanosis (bluish discoloration)
  • Hyperpnea (rapid, deep breathing)
  • Irritability or distress
  • Decreased intensity of heart murmur during spell
  • Occurs in children with known or suspected Tetralogy of Fallot
  • Often triggered by crying, feeding, defecation, or agitation 1
  • May lead to syncope or loss of consciousness if severe

Seizures

• Characteristic presentation:
  • Rhythmic jerking movements (in generalized tonic-clonic seizures)
  • Altered consciousness
  • Possible urinary incontinence
  • Post-ictal confusion/drowsiness
  • May have focal features (affecting only one part of body)
  • Can occur with or without fever 1
  • Eyes typically open during epileptic seizures (vs. closed in psychogenic events) 2

Management Algorithm

For Suspected Tet Spell:

1. Position the child in knee-chest position (knees drawn up to chest)
2. Administer morphine: 0.1 mg/kg IV/IM immediately 1
3. Provide supplemental oxygen if available
4. Activate emergency services immediately
5. Calm the child and environment to reduce agitation
6. Monitor vital signs continuously until emergency services arrive

For Suspected Seizure:

1. Help the person to the ground and place on their side in recovery position 1
2. Clear the area around them to prevent injury 1
3. Stay with the person throughout the seizure 1
4. Time the seizure - activate EMS if:
   • First-time seizure
   • Seizure lasts >5 minutes
   • Multiple seizures without return to baseline
   • Seizure occurs in water
   • Traumatic injuries occur
   • Breathing difficulties or choking present
   • Seizure in infant <6 months
   • Seizure in pregnant individual
   • Person doesn't return to baseline within 5-10 minutes after seizure 1
5. Do not restrain the person or put anything in their mouth 1

Critical Distinctions

Infantile Reflex Syncopal Attacks vs. Seizures

• Infantile reflex syncopal attacks (pallid breath-holding spells) are triggered by brief unpleasant stimuli and caused by vagally mediated cardiac inhibition 1
• These can be mistaken for seizures but are a form of reflex syncope 1

Psychogenic Non-Epileptic Seizures vs. True Seizures

• Psychogenic events often feature:
  • Eyes closed during unconsciousness
  • Pelvic thrusting movements
  • Eye fluttering
  • Longer duration of apparent loss of consciousness
  • Asymmetrical and asynchronous movements 2
  • Normal EEG during typical event 2

Common Pitfalls to Avoid

1. Misdiagnosing a Tet spell as a seizure: Delays proper management with morphine and positioning
2. Administering anticonvulsants for a Tet spell: Ineffective and wastes critical time
3. Restraining a child during a seizure: Can cause injury 1
4. Putting objects in the mouth during seizures: Dangerous and unnecessary 1
5. Giving antipyretics during febrile seizures: Not effective for stopping or preventing seizures 1
6. Assuming all seizure-like events in children with known epilepsy are seizures: May miss Tet spells in children with both conditions

When to Refer for Further Evaluation

• All children with first-time Tet spells require immediate cardiology evaluation
• All children with first-time seizures require neurological evaluation 1
• Children with known Tetralogy of Fallot experiencing increased frequency of Tet spells may need surgical intervention

Remember that accurate differentiation between these conditions is critical for appropriate management and preventing adverse outcomes. When in doubt, activate emergency services promptly.