Overview
This episode of The Curbsiders podcast features an evidence-based discussion of syncope evaluation and management in internal medicine, focusing on key definitions, diagnostic frameworks, relevant guidelines, and practical clinical decision-making.
Definitions and Categories of Syncope
- Syncope is a sudden, transient loss of consciousness and postural tone due to decreased cerebral blood flow, resolving quickly.
- Pre-syncope involves prodromal symptoms without full loss of consciousness and carries similar risks to syncope.
- Major syncope etiologies: reflex (vasovagal), orthostatic, and cardiac (arrhythmic or structural).
- Cardiac causes are divided into rhythm (fast or slow arrhythmias) and structural (valvular, obstructive, pump failure, vascular).
History, Exam, and Risk Stratification
- Most low-risk syncope diagnoses are made by thorough history, looking for classic prodromes (sympathetic then parasympathetic symptoms).
- Features like lateral tongue biting and prolonged postictal state raise suspicion for seizure over syncope.
- Urinary incontinence is not a reliable distinguishing factor.
- Myoclonic jerking may occur after syncope but prolonged tonic-clonic activity suggests seizure.
- The Canadian Syncope Risk Score is recommended for risk assessment and is available in app form.
Diagnostic Testing and Workup
- Essential tests: orthostatic vital signs, cardiac and neurologic exams, and EKG for all patients.
- Additional testing (labs, imaging) is based on suspicion for non-benign etiologies.
- Brain imaging and EEG are not indicated unless there are focal neurological deficits or events suggestive of seizure/stroke.
Pulmonary Embolism and Syncope
- The PESIT trial showed elevated PE incidence in select hospitalized first-episode syncope patients.
- If no low-risk etiology is clear, calculate the Wells score and check D-dimer; pursue Chest CT only if positive.
- Segmental/sub-segmental PEs may cause syncope, possibly via reflex pathways.
Cardiac Evaluation and Monitoring
- Echocardiography should be reserved for history, exam, or EKG findings suggestive of structural heart disease.
- Widened QRS or conduction abnormalities increase risk; consider electrophysiology referral and monitoring.
- Syncope with chest pain or concerning cardiac history warrants ACS evaluation.
- Ambulatory rhythm monitoring is indicated for recurrent or high-risk unexplained syncope; choose duration/type based on episode frequency.
Patient Counseling and Follow-Up
- Simple vasovagal syncope has no increased subsequent risk; reassurance and hydration are key.
- Most low-risk patients do not require urgent follow-up beyond routine primary care.
Recommendations / Advice
- Prioritize detailed history and exam, including orthostatics and EKG, for every syncope patient.
- Use risk scores to guide disposition; image for PE only if warranted by risk assessment.
- Reserve echo and neurology testing for specific findings.
- Refer to European Society of Cardiology syncope guidelines for user-friendly algorithms.
Decisions
- Low-risk vasovagal syncope managed with reassurance and outpatient follow-up.
- Moderate/high-risk or unclear cases require inpatient evaluation and specialized testing as guided by risk stratification.
Action Items
- TBD – All Providers: Incorporate Canadian Syncope Risk Score into syncope assessments.
- TBD – Providers: Obtain orthostatic vitals and EKG on all presenting syncope patients.
- TBD – Providers: Use targeted testing (echo, D-dimer, imaging) based on risk and clinical suspicion.
- TBD – Providers: Provide patient education regarding future syncope prevention, especially hydration.
Questions / Follow-Ups
- Clarify which patients might benefit from ambulatory monitoring versus immediate hospitalization.
- Determine protocols for PE workup in recurrent but low-risk syncope presentations.