Syncope

Syncope is temporary loss of consciousness and muscle tone due to decreased cerebral blood flow. It is otherwise known as fainting or blackout. Syncope is a common pediatric problem that, in contrast to that in adults, usually has a benign etiology. However, it can be a sign of a serious underlying disorder, so a complete H&P is critical.

Differential Diagnosis

• Vasovagal
  –Most common etiology (more than 50%)
  –Also known as neurocardiogenic or vasodepressor syncope
  –Typical in adolescents; greater in females
  –Occurs after prolonged standing in a warm place; with emotional upset, pain, hunger, the sight of blood; crowded places

• Postural/orthostatic hypotension
  –Occurs when standing up quickly
• Micturation syncope (a rare form)
• Breath-holding spells
  –Usually at ages 1–5 years
  –Two types: Cyanotic (80%) vs pale (20%)
  –Cyanotic spells start with crying
  –Provoked by anger, frustration, or pain, or used as an attention-getting behavior
  –May have generalized clonic jerks
  • Cardiac etiologies (less common)
    –Arrhythmias
    –Supraventricular tachycardia is the most common cause
    –Long QT syndrome (QTc >0.44 seconds): Causes ventricular arrhythmias, Romano-Ward (autosomal dominant), Jervell and Lange-Nielsen (autosomal recessive with deafness)
    –Medications (e.g., cisapride)
    –Sinus node dysfunction and atrioventricular block may lead to bradyarrhythmias
    –Post-op congenital lesions and dilated cardiomyopathy lead to arrhythmias
    –Structural cardiac disease
    –Severe obstructive lesions (e.g., hypertrophic obstructive cardiomyopathy, aortic stenosis, pulmonic stenosis, atrial myxomas, and pulmonary hypertension)
  • Hysterical fainting
  • Migraine
  • Hyperventilation
  • Pregnancy
  • Anemia or hypovolemia
  • Hypoglycemia
  • Carbon monoxide poisoning
  • Medications and drugs of abuse
  • Electrolyte abnormalities
  • Intracranial hypertension
  • Epilepsy may mimic syncope
  • Adrenal insufficiency

  Workup and Diagnosis

  • History: Most important aspect to guide diagnostic workup
    –Vasovagal syncope: Prodromal symptoms (e.g., cold, clammy skin; pallor; nausea; blurry vision; yawning; dizziness; lightheadedness; palpitations; hyperventilation)
    –Duration: Vasovagal syncope is short (seconds to minutes)
    –Inciting situations
    –Lightheadedness: In orthostatic hypotension
    –Syncope at rest or recumbent in seizure or arrhythmia; syncope without prodrome or with exercise/exertion in cardiac etiology
    –Auras in migraine headaches
    –Seizures may have incontinent or post-ictal state or generalized tonic-clonic movements
    –Family history: Sudden or unexplained deaths, cardiac abnormalities, seizures, or deafness
  • Physical exam
    –Orthostatic blood pressures and pulse
    –Perform a thorough cardiac and neurologic exam
  • Extensive laboratory workup is not usually needed
    –Most clinicians would do an ECG
    –Tilt-table testing to diagnose vasovagal syncope is controversial as it is not very reproducible
    –Labs might include CBC, glucose, electrolytes, drug screen, carboxyhemoglobin, EEG, or head CT as guided by history; if cardiac abnormalities are suspected, may get a chest X-ray, Holter monitoring, or exercise testing

  Treatment

  • Vasovagal syncope
    –Educate family and patient to recognize precipitating factors and to avoid hypovolemia
    –Have patient lie in a recumbent position until the symptoms subside
    –Reassurance
  • If severe, β-blockers can be used for recurrent vasovagal syncope
  • For breath-holding spells, education is also imperative
  • Iron has also been advocated in patients who are found to be iron-deficient
  • Cardiac abnormalities are treated on an individual basis
    –Structural lesions will require repair
    –Arrhythmias may require medication or pacing
    –Prolonged QT is treated with β-blockers, left cardiac sympathetic denervation, or demand cardiac pacing

Book Source Details

• Book Title: In A Page: Pediatric Signs and Symptoms
• Author(s): Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
• Year of Publication: 2007
• Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.

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Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: In A Page: Pediatric Signs and Symptoms Authors: Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-4051-0427-9

 » Next page: Vertigo (In A Page: Pediatric Signs and Symptoms)

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