What are the symptoms and management of vasovagal (vasovagal syncope) syncope?

Symptoms and Management of Vasovagal Syncope

Vasovagal syncope is characterized by a transient loss of consciousness due to global cerebral hypoperfusion, with typical symptoms including lightheadedness, dizziness, nausea, sweating, pallor, and visual disturbances that precede the fainting episode. 1

Symptoms of Vasovagal Syncope

Prodromal Symptoms (Presyncope)

• Typical symptoms include:
  • Lightheadedness/dizziness
  • Nausea
  • Feeling warm/hot or cold
  • Abdominal pain
  • Visual disturbances (black spots, blurred vision, tunnel vision)
  • Weakness
  • Sweating
  • Pallor/paleness 1

During Syncope

• Complete loss of consciousness (typically lasting less than 20 seconds) 1
• Fall and loss of postural tone
• Possible brief myoclonic jerks in 90% of cases 1
• Possible incontinence 1

Post-Syncope

• Quick return to full consciousness
• Fatigue (common after the attack)
• Children may fall asleep 1
• Usually no confusion (unlike seizures) 2

Pathophysiology

Vasovagal syncope occurs through a brain reflex that affects circulation in two primary ways:

1. Blood vessels dilate excessively, causing blood to pool in lower extremities and blood pressure to drop
2. The brain may signal the heart to slow down or temporarily stop (bradycardia) 1

This results in decreased cerebral blood flow leading to loss of consciousness. The underlying mechanism involves:

• Decreased blood return to the heart
• Decreased cardiac output
• Global cerebral hypoperfusion 1

Management of Vasovagal Syncope

Immediate Management During Presyncope

1. Assume a safe position immediately - lie down or sit down when symptoms begin 1

2. Perform physical counterpressure maneuvers (PCMs) to prevent progression to syncope:

   • Lower-body PCMs (preferred over upper-body maneuvers):
     • Leg crossing with tensing of leg, abdominal, and buttock muscles
     • Squatting 1
   • Upper-body PCMs:
     • Arm tensing (gripping opposing hands and pulling)
     • Isometric handgrip (clenching fist with maximum contraction)
     • Neck flexion 1

3. If no improvement occurs within 1-2 minutes, or symptoms worsen or recur, activate emergency services 1

Long-term Management

1. Patient education and reassurance 3

   • Explain the benign nature of the condition
   • Teach recognition of warning signs
   • Instruct on proper PCM techniques

2. Lifestyle modifications:

   • Increase fluid intake (approximately 2L per day)
   • Increase salt intake (unless contraindicated)
   • Monitor urine color (should be light yellow) 1
   • Avoid known triggers (prolonged standing, hot environments, dehydration)

3. Pharmacological options (for recurrent, problematic cases):

   • Fludrocortisone and midodrine have shown significant reduction in syncope recurrences 3
   • Beta-blockers (controversial - metoprolol was not helpful in a pivotal trial) 3

4. Advanced interventions (for refractory cases):

   • Pacing therapy with specialized sensors in carefully selected patients 3

Special Considerations

• Do not use PCMs when symptoms of heart attack or stroke accompany presyncope 1
• Vasovagal syncope can lead to injury in 30% of patients presenting to emergency departments 1
• Recurrent episodes occur in approximately 20% of individuals during the first 4 years after an initial episode 1
• Older patients may have atypical presentations or multiple contributing factors 3

When to Seek Medical Attention

• First episode of syncope
• Recurrent episodes
• Syncope with injury
• Syncope without prodromal symptoms
• Syncope during exercise or when supine
• Family history of sudden cardiac death

By recognizing the symptoms early and implementing appropriate management strategies, most patients with vasovagal syncope can effectively control their condition and prevent progression to full syncope episodes.