Syncope In Pediatric Patients: A Practical Approach To Differential Diagnosis And Management In The Emergency Department

Table of Contents

 

1. Abstract
2. Case Presentations
3. Introduction
4. Critical Appraisal of the Literature
5. Etiology And Pathophysiology
   1. Pathophysiology Of Neurocardiogenic (Vasovagal) Syncope
6. Differential Diagnosis
   1. Cardiogenic Etiologies Of Syncope
      1. Hypertrophic Cardiomyopathy
      2. Supraventricular Tachycardia
      3. Other Cardiogenic Etiologies
   2. Noncardiac Etiologies Of Syncope That Require Further Evaluation
      1. Pregnancy And Ectopic Pregnancy
      2. Hypoglycemia
      3. Other Noncardiac Etiologies
   3. Noncardiac, Non–Life-Threatening Etiologies Of Syncope
      1. Neurocardiogenic Syncope
      2. Seizure
      3. Breath-Holding Spells
      4. Postural Orthostatic Tachycardia Syndrome
      5. Psychogenic Pseudosyncope
7. Prehospital Care
8. Emergency Department Evaluation
   1. Initial Management
   2. History
9. Diagnostic Studies
   1. Evidence Against Routine Testing
      1. Head-Up Tilt-Table Test
      2. Orthostatic Vital Sign Measurements
      3. Electroencephalogram And Computed Tomography
      4. Cardiac Enzymes
10. Treatment
11. Special Populations
    1. Patients With Known Cardiac Disease
12. Controversies And Cutting Edge
13. Disposition
14. Summary
15. Risk Management Pitfalls In Pediatric Patients With Syncope
16. Time- And Cost-Effective Strategies
17. Case Conclusions
18. Clinical Pathway For The Management Of Pediatric Patients With Syncope
19. Tables and Figures
    1. Table 1. Etiologies Of Syncope
    2. Table 2. Medications That Prolong The QT Interval
    3. Table 3. - Red Flags - And - Green Lights - In Patients With Syncope
    4. Table 4. Management Of Various Etiologies Of Syncope Cardiac & Non Cardiac
    5. Figure 1. Hypertrophic Cardiomyopathy On Electrocardiogram
    6. Figure 2. Long QT Syndrome On Electrocardiogram
    7. Figure 3. Delta Waves On Electrocardiogram Consistent With Wolff-Parkinson-White Syndrome
    8. Figure 4. Atrioventricular Re-Entrant Tachycardia In Wolff-Parkinson-White Syndrome
    9. Figure 5. Types Of Heart Block On Electrocardiogram
    10. Figure 6. Brugada Syndrome Patterns On Electrocardiogram
20. References

Abstract

Syncope is a condition that is often seen in the emergency department. Most syncope is benign, but it can be a symptom of a life-threatening condition. While syncope often requires an extensive workup in adults, in the pediatric population, critical questioning and simple, noninvasive testing is usually sufficient to exclude significant or life-threatening causes. For low-risk patients, resource-intensive workups are rarely diagnostic, and add significant cost to medical care. This issue will highlight critical diseases that cause syncope, identify high-risk “red flags,” and enable the emergency clinician to develop a cost-effective, minimally invasive algorithm for the diagnosis and treatment of pediatric syncope.

Case Presentations

A 10-year-old previously healthy boy presents after “passing out” and experiencing chest pain while playing basketball with friends earlier that evening. The patient reports occasional chest pain with exertion. Today, he also had chest pain while running, collapsed, and had a loss of consciousness for 4 to 5 seconds. He then returned to baseline. He has no prior history of syncope and no recent infections. He denies drug use. On physical examination, there is no evidence of acute distress, and he has normal pulmonary and cardiac examinations. You immediately order an ECG. Do you also need to obtain troponins, D-dimer, or coagulation studies? Does he also need an echocardiogram? You want the patient to see a cardiologist, but does this need to happen in the middle of the night?

A 16-year-old previously healthy adolescent girl presents with multiple episodes of syncope over the last 24 hours. Her preceding symptoms include the sensation that her heart was racing, seeing spots in her visual fields, and feeling short of breath. She had been feeling unwell for 4 days with a dry cough, but no other cold-like symptoms. The first episode of syncope occurred the previous night after getting up from seated position and walking. Her second episode of syncope was this morning, again, after getting up and walking. She had her third episode of syncope today while seated on a couch. This episode was witnessed by friends who state she was unconscious for a few seconds. She denies any pain with these episodes. She currently has no chest pain, but feels short of breath. She has no risk factors for pulmonary embolism and no family history of early cardiac death or clotting disorders. Her last menstrual period was 2 weeks ago. As you order an ECG and a pregnancy test, you think about what else you need to do for this patient.

An 18-year-old previously healthy adolescent girl presents after fainting. She was standing and waiting for the subway when she "felt the room closing in” and the “world going dark.” The next thing she remembers is lying on the ground with people looking down at her. The patient reports recent cold symptoms and decreased appetite. She denies the use of drugs or alcohol. She denies pregnancy. This has happened one other time, several years ago. Now she feels she has returned to her baseline. What diagnostic testing is helpful in the diagnosis of this patient? What further evaluation does she need, if any? How should she be managed? Does she need admission?

Introduction

Syncope is defined as a transient loss of consciousness and postural tone due to an alteration in cerebral perfusion, usually associated with spontaneous recovery. In pediatric patients, syncope is most often a brief episode with complete recovery, without sequelae. These typical episodes, however, must be differentiated from those with rare, life-threatening etiologies. Syncope is most common in teenagers, with the incidence peaking in patients aged between 15 and 19 years. Fifty percent of people report an episode of syncope during adolescence.¹ Syncope accounts for 1% to 3% of emergency department (ED) visits, with an overall incidence in the pediatric population of 0.1% to 0.5%.^2,3 Syncope must be distinguished from all other causes of loss of consciousness, such as seizures, head trauma, and psychiatric causes.

There are many ways to classify syncope, but the simplest is to divide the causes of syncope into 2 groups: cardiac and noncardiac etiologies. While cardiac causes represent the minority of syncope cases, they should not be missed,¹ as they can result in sudden death.⁴ As many as 1% to 5% of syncopal events may be related to underlying cardiac disease.⁵ This issue of Pediatric Emergency Medicine Practice will help emergency clinicians develop a broad differential diagnosis, use a classification scheme to identify the causes of syncope, and determine appropriate evaluation of the patient. Most importantly, this issue will help emergency clinicians identify the red flags for etiologies that must not be missed in the evaluation of pediatric syncope in the ED.

Critical Appraisal Of The Literature

A literature search was performed in PubMed using the terms syncope, fainting, blackout, and vasovagal. The search was limited to articles published since 1960 that involved patients aged 0 to 18 years. The term emergency department was also included in a subsequent search. This search was limited by age, English language, and human subjects. These searches identified several thousand articles that were screened by title, which resulted in approximately 150 articles that were considered for inclusion. The Cochrane Database of Systematic Reviews, Evidence-Based Medicine Reviews: Best Evidence (American College of Physicians), Database of Abstracts of Reviews of Effectiveness (DARE), and the National Guideline Clearinghouse were all queried for articles related to syncope in adults or children. The results of these queries produced more than 130 articles that were reviewed in full.

Risk Management Pitfalls In Pediatric Patients With Syncope

1. “The teenage patient assured me that she couldnot be pregnant, so I did not order an HCG test.”

Ensuring that adolescent patients have a chance to speak with providers without their parents present is an expected part of adolescent medicine and often allows capture of sensitive information. The emergency clinician must verify that teenage girls who report no sexual intercourse are really not pregnant. Results should be provided in a confidential manner based upon individual state law.

2. “It was such a classic story for neurocardiogenic syncope, except for the family history of sudden death, that I did not perform an ECG.”

Cardiac abnormalities can easily be overlooked. Most of the rules regarding limiting extensive testing presume a normal ECG. A family history of sudden death could suggest a genetically inherited cause of cardiac syncope.

3. “I asked if there were any medical problems that run in the family, but the patient didn’t tell me that her sister is deaf.”

Many families do not recognize deafness as a reportable medical problem, so this must be asked specifically. This is also true for sudden unexplained deaths in the family. Patients may not offer this information unless it is explicitly asked.

4. “The coach, parents, and patient all told me he was just overexerted while running. They think he can play in the state championship game tomorrow.”

Don’t be swayed by elite athletes, coaches, or family members minimizing symptoms. The primary goal is to ensure the safety of the patient. If syncope occurred during activity, then the patient should refrain from strenuous activity until cleared by cardiology.

5. “The patient had a history and physical examination consistent with neurocardiogenic syncope without any evidence of injury. The mother was very concerned about a brain tumor, so I obtained a CT scan to reassure her.”

Sometimes the path of least resistance can do more harm than good. Do not unnecessarily irradiate pediatric patients, as this exposes them to radiation that increases their long-term risk of cancer.

6. “I looked at the ECG quickly to check for ischemic changes as I do for my adult patients and was reassured by the ECG.”

Remember ECG analysis in pediatric patients is not primarily to assess for myocardial infarctions, and emergency clinicians must change their point of reference and concentrate on cardiac abnormalities that can cause syncope in children (eg, prolonged QT, Wolff-Parkinson- White syndrome, Brugada syndrome, or myocarditis/pericarditis).

7. “The nurse checked orthostatic vitals. I knew the patient could not be volume depleted, so we discharged her without fluid resuscitation.”

Orthostatic vitals have been shown to be neither sensitive nor specific for volume depletion. Patients who are orthostatic by symptom description should be hydrated and reassessed prior to discharge.

8. “The patient had known congenital cardiac disease, but the episode sounded neurocardiogenic so I sent him home.”

Children with underlying cardiac disease warrant consultation with pediatric cardiology prior to discharge to ensure that the syncope is not related to their underlying condition.

9. “A pediatrician referred this patient with classic syncope to the ED. His ECG was normal, but the primary care physician wanted him admitted for overnight observation.”

Routine admission for a patient who has returned to baseline, has no cardiac risk factors, and has a normal ECG is unnecessary and not cost-effective. To date, there are no data that show that routine admission after a syncopal event alters morbidity or mortality, and admission increases healthcare costs and may expose patients to additional risks.⁸⁴

10. “I know the patient had no cardiac risk factors, but I wanted to be thorough, so I ordered electrolytes, an EEG, an echo, and head-up tilttable testing.”

Extensive testing in low-risk groups rarelyimproves diagnostic yield and results

Tables and Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study is included in bold type following the references, where available. The most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

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