Syncope Differentials in Dogs and Cats: Practical Triage Algorithm

Rapid Algorithm

• Confirm true syncope versus seizure, weakness, or vestibular events using event history clues.
• Assess perfusion, rhythm, and hemodynamic risk immediately after presentation.
• Prioritize cardiogenic causes when collapse pattern and recovery profile fit.
• Use targeted diagnostics to separate rhythm, structural, and systemic contributors.
• Set return precautions and follow-up intervals based on recurrence severity.

Diagnostic Flow

• Event history quality is critical for separating syncope from seizure-like episodes.
• ECG and blood pressure are high-yield first-tier assessments in many cases.
• Cardiac imaging and rhythm monitoring refine diagnosis in recurrent episodes.
• Laboratory screening helps identify metabolic and perfusion contributors.
• Serial reassessment is useful when initial diagnostics are nondiagnostic but suspicion remains.

Treatment Flow

• Stabilize airway and perfusion first in unstable collapse presentations.
• Treat arrhythmia or structural contributors according to confirmed risk profile.
• Address systemic contributors such as severe anemia or electrolyte derangements.
• Implement monitoring strategy for recurrence and near-syncopal warning signs.
• Provide owner guidance for event logging and emergency escalation triggers.

Exam Traps

• Assuming all collapse events are neurologic can delay cardiogenic diagnosis.
• Ignoring event timing and trigger context weakens differential ranking.
• Skipping rhythm evaluation in recurrent episodes is a common mistake.
• Failure to provide return precautions increases risk between visits.
• Relying on one normal snapshot can miss episodic arrhythmia pathology.

Practice Prompts

• What historical clues separate syncope from seizure episodes?
• When should cardiogenic causes be prioritized first?
• Which diagnostics best capture intermittent arrhythmia causes?
• What follow-up plan reduces missed recurrence risk?
• How can owners document episodes to improve diagnostic clarity?

Related Content

• Return to NAVLE Topics (Cardiology and CHF are under Topics)
• CHF Staging Overview for Dogs and Cats
• Dog and Cat Murmur Approach: Triage and Workup Logic
• Use the Emergency Drug Chart
• Try 5 free practice questions on this topic
• Unlock unlimited practice (Premium)

Sources and Review Notes

• Drug label search (DailyMed)
• IRIS stages
• Normal lab values
• Heartworm treatment protocol
• Lab test protocols
• Microchip lookup
• Vertebral Heart Score
• BCS charts
• ACVIM cardiology consensus guideline references
• Dental charts
• AAHA vaccination guidelines
• Flea/tick product info
• Dog/cat breed search
• RECOVER CPR guidelines

Last reviewed: February 13, 2026