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Syncope

7 min read

SYNCOPE IN CHILDREN

Objectives

  • Understand the term syncope.
  • Differentiate the serious causes of syncope from those that are benign.
  • Know the appropriate testing needed in the evaluation of syncope based upon the presenting history.

Definitions to Know

  • Palpitations: Sensation of strong, rapid, or irregular heart beats.
  • Syncope: Transient loss of consciousness and postural tone due to generalized cerebral ischemia with rapid and spontaneous recovery.
  • Presyncope: No complete loss of consciousness occurs.

Syncope Mimics

Disorders without impairment of consciousness

  • Drop attacks.
  • Cataplexy/Narcolepsy.
  • Psychogenic pseudo-syncope.
  • Transient ischemic attacks.

Disorders with loss of consciousness

  • Metabolic disorders.
  • Epilepsy.
  • Intoxications.
  • Vertebrobasilar transient ischemic attacks.

Epidemiology & Characteristics Z

  • Affects 15% of children between 8-18 Y.
  • Uncommon under age 7 Y therefore think about:
    • Seizure disorders.
    • Breath holding.
    • Primary cardiac dysrhythmias.
  • Cardiovascular causes unusual but life-threatening:
    • Congenital malformations.
    • Valvular disease.
    • Electrical abnormalities.

Vasovagal Events

  • 30% to 50% of cases.
  • Decreased PVR.
  • Decreased venous return.
  • Decreased cardiac output.
  • Hypotension.
  • Bradycardia.
  • In teens - think about pregnancy and drug abuse.

Likely Causes in Children

  • Vasovagal.
  • Situational.
  • Psychiatric.
  • Long QT.
  • WPW syndrome.
  • RV dysplasia.
  • Hypertrophic cardiomyopathy.
  • Catecholaminergic VT.
  • Other genetic syndromes.

Differential Diagnosis: Seizures vs Hypotension

ObservationSeizureInadequate Perfusion
OnsetSuddenMore gradual
DurationMinutesSeconds
JerksFrequentRare
HeadacheFrequent (after)Occasional (before)
Confusion afterFrequentRare
IncontinenceFrequentRare
Eye deviationHorizontalVertical (or none)
Tongue bitingFrequentRare
ProdromeAuraDizziness
EEGOften abnormalUsually normal

Causes of True Syncope Z

Neurally-Mediated

  1. Vasovagal
  • Carotid Sinus
  • Situational
    • Cough
    • Post-Micturition

Orthostatic

  1. Drug-Induced
  • Autonomic Nervous System Failure
    • Primary
    • Secondary

Cardiac Arrhythmia

  1. Brady
  • SN Dysfunction
  • AV Block
  • Tachy
    • VT
    • SVT
    • Long QT Syndrome

Structural Cardio-Pulmonary

  1. Acute Myocardial Ischemia
  • Aortic Stenosis
  • HCM
  • Pulmonary Hypertension
  • Aortic Dissection

Unexplained Causes = Approximately 1/3

Clinical Evaluation

Key Questions to Address with Initial Evaluation

  • Is the loss of consciousness attributable to syncope or not?
  • Is heart disease present or absent?
  • Are there important clinical features in the history that suggest the diagnosis?

Important Historical Features

Circumstances just prior to attack Z

  • Position (supine, sitting, standing)
  • Activity (rest, change in posture, during or immediately after exercise, during or immediately after urination, defecation or swallowing)
  • Predisposing factors (crowded or warm place, prolonged standing post-prandial period) and of precipitating events (fear, intense pain, neck movements)

Onset of the attack

  • Nausea, vomiting, feeling cold, sweating, pain in chest

The Attack (Eye witness)

  • Skin color (pallor, cyanotic).
  • Duration of loss of consciousness.
  • Movements (tonic-clonic, etc.).
  • Tongue biting.

End of the attack

  • Nausea, vomiting, diaphoresis, feeling cold, muscle aches, confusion, skin color, wounds.

Background

  • Number and duration of syncope spells.
  • Family history of arrhythmic disease or sudden death.
  • Presence of cardiac disease.
  • Neurological disease.
  • Medications (Hypotensive, negative chronotropic and antidepressant agents).

Clinical Features Suggesting Specific Cause of Syncope Z

Neurally-Mediated Syncope Z

  • Absence of cardiac disease.
  • Long history of syncope.
  • After sudden unexpected, unpleasant sensation.
  • Prolonged standing in crowded, hot places.
  • Nausea vomiting associated with syncope.
  • During or after a meal.
  • With head rotation or pressure on carotid sinus.
  • After exertion.

Syncope due to Orthostatic Hypotension

  • After standing up.
  • Temporal relationship to taking a medication that can cause hypotension.
  • Prolonged standing.
  • Presence of autonomic neuropathy.
  • After exertion.

Cardiac Syncope

  • Presence of structural heart disease.
  • With exertion or supine.
  • Preceded by palpitations.
  • Family history of sudden death.

Physical Examination

Initial Exam: Complete Physical Examination

  • Vital signs:
    • Heart rate.
    • Orthostatic blood pressure change.
  • Cardiovascular exam: Is heart disease present?
    • ECG: Long QT, pre-excitation, conduction system disease.
    • Echo: LV function, valve status, HCM.
  • Neurological exam.

Orthostatic Measurements

  • Classically, abnormal if systolic BP decreases by more than 20 points and/or pulse increases in pulse rate of more than 20 beats per minute after a change from supine to standing.
  • If there is only a pulse increase but no drop in blood pressure, the test is less significant.

Diagnostic Testing & Management

Diagnostic Objectives

  • Distinguish true syncope from syncope mimics.

  • Determine presence of heart disease and risk for sudden death.

  • Establish the cause of syncope with sufficient certainty to:

    • Assess prognosis confidently.
    • Initiate effective preventive treatment.

Electrocardiogram (ECG)

  • Yield for specific diagnosis low (5%).
  • Risk free and relatively inexpensive.
  • Abnormalities (BBB, previous MI, nonsustained VT) guide further evaluation.
  • Recommended in almost all patients.

Laboratory Tests

  • Routine use not recommended
    • May be glucose?
  • Should be done only if specifically suggested by H&P.
  • Laboratory is often normal but may include:
    • Electrolytes / Ca++, Mg++, PO4.
    • CBC with differential.
    • Cardiac enzyme.

Neurologic Testing

  • EEG - not useful unless seizures.
  • Brain imaging - not useful unless focality.
  • Neurovascular studies.
    • No studies.
    • May be useful if bruits, or hx suggests vertebrobasilar insufficiency.

Radiology

  • CXR offers little.
  • CT or MRI of the brain and neck may be indicated if considering seizures or injury.

Advanced Cardiac Studies

  • ECG/Holter.
  • Echocardiography
  • Cardiac MRI
  • Continuous cardiac monitoring
  • Stress ECG
  • Genetic testing

Mortality Risk & Prognosis

“…CARDIAC SYNCOPE CAN BE A HARBINGER OF SUDDEN DEATH.”

  • Survival with and without syncope (adults and children).
  • 6-month mortality rate of greater than 10%.
  • Cardiac syncope doubled the risk of death.
  • Includes cardiac arrhythmias.

img-0.jpeg

Soteriades ES, et al. N Engl J Med. 2002;347:878.

Case Study 1

Presentation:

  • 11-year-old girl passed out during reading; awoke after 3 min.
  • She was stiff with eyes rolled back ~ approx. 3 min.
  • Now awake and alert; no retractions; skin color is normal.
  • Normal appearance, normal breathing, normal circulation.
  • Vital signs: HR 70; RR 20; BP 90/60; T 37.7° C Wt 39 kg; O₂ sat 99%.
  • Three similar episodes; Preceded by palpitations, one of them associated with “exercise.” Z
  • PMH and FH: Negative.

Discussion:

  • What is your general impression of this patient?

Clinical Features: Your First Clue

  • Loss of consciousness.
  • Lasted only a few minutes.
  • Minimal or no postictal state.
  • No stigmata of seizure: Urinary incontinence, bitten tongue, witnessed tonic-clonic activity.

Key Questions to Address (Review):

  • Is the loss of consciousness attributable to syncope or not?
  • Is heart disease present or absent?
  • Are there important clinical features in the history that suggest the diagnosis?

Status:

  • Stable
  • Patient with syncope.
  • In no distress; normal exam.
  • Concerning/ominous history.

Question:

  • What are your initial management priorities?

Differential Diagnosis:

  • Structural heart defect:
    • Known Congenital heart disease (Ebstein’s anomaly, LTGA, ASD)
    • Hypertrophic cardiomyopathy
    • Anomalous origin of the LCA
    • Myocarditis
    • Arrhythmogenic RV dysplasia
    • Coronary artery disease
    • Primary or secondary pulmonary hypertension.
  • Normal heart structure:
    • WPW syndrome.
    • Long or short QT syndrome.
    • Brugada syndrome.
    • CPVT.

img-1.jpeg

Loc 55545-5000 25 mm/sec 10.0 mm/mV W 0.50-40

Long QT Syndrome

Jervell-Nielson-Lange

img-2.jpeg

QT (corrected)

450 m sec is long

Overview

  • Inherited genetic disorder that puts the child at risk for paroxysmal ventricular tachycardia /ventricular fibrillation and sudden death.
  • May also result from electrolyte imbalance, malnutrition (anorexia and bulimia), myocarditis and CNS trauma
  • Speculation that it may be associated with SIDS (unproven)
  • No warning; results in death.

What to look for in the Department: EKG

  • Long QT syndrome:
    • Congenital long QT associated with hypertrophic cardiomyopathy.
    • Long QT defined as corrected QT longer than 0.44 s
    • T wave alternans sometimes present.
    • Can have normal ECG in the department.
    • Two clinical syndromes not associated with structural heart disease: Romano-Ward and Jervell-Lange-Nielsen.

img-3.jpeg

torrsado de pointes.

Final Words of Wisdom

-IS IT SYNCOPE?-

  • History is key!!!!
  • Orthostatics:
    • Take the time to do them correctly.
  • Cardiac vs Non-cardiac:
    • If you are not confident that it is NOT cardiac → REFER.
  • ECG
    • Use it if you got ‘em!

.

which of following cardiac syncope, standing long time, dehydration, gym, family history of sudden death suggest qt -

or during exercise

Vasovagal attacks due .. .

Graph View

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