Collapse and syncope

Quick Overview

Collapse and syncope are common emergency presentations requiring rapid differentiation from seizures and cardiac arrest. Syncope = transient loss of consciousness (TLOC) with loss of postural tone due to cerebral hypoperfusion, followed by spontaneous complete recovery. NICE CG109 provides structured risk stratification to identify high-risk patients needing admission and those suitable for outpatient management.

Core Facts & Concepts

Key Definitions:

• Syncope: TLOC <20 seconds, rapid onset, spontaneous complete recovery
• Cardiac syncope: 30-day mortality up to 10% vs <1% for reflex syncope
• Postural hypotension: ≥20 mmHg systolic OR ≥10 mmHg diastolic drop within 3 minutes of standing

Critical Time Points:

• Measure BP at 0, 1, and 3 minutes during postural assessment
• ECG within 1 hour of presentation (NICE CG109)
• Observe 4-6 hours if suspected arrhythmic syncope

Classification by Mechanism:

Problem-Solving Approach

Distinguishing TLOC Causes:

1. Syncope vs Seizure:

   • Syncope: Brief (<20s), rapid recovery, pallor, upright position
   • Seizure: Prolonged (>5 min), post-ictal confusion, cyanosis, any position, tongue-biting (lateral), incontinence common

2. Cardiac Arrest vs Syncope:

   • Cardiac arrest: No pulse, no breathing, requires CPR
   • Syncope: Pulse present, breathing continues, self-limiting

🚩 ECG Red Flags (NICE CG109):

• QTc >450 ms (men) or >470 ms (women) → Long QT syndrome
• Brugada pattern (coved ST elevation V1-V2)
• Epsilon waves or TWI V1-V3 → ARVC
• Q waves suggesting MI
• Mobitz II or complete heart block
• Alternating LBBB/RBBB
• SVT/VT on ECG

Analysis Framework

Canadian Syncope Risk Score (7-day serious outcome):

• Score 0: <1% risk (safe discharge)
• Score ≥3: 10% risk (admit)

NICE CG109 Admission Criteria:

• ECG abnormality suggesting arrhythmia
• Heart failure (clinical or ECG evidence)
• Exertional syncope or FH sudden cardiac death <40 years
• New/unexplained breathlessness
• Murmur suggesting valvular disease

Visual Aid

Postural BP Measurement Technique:

Key Points Summary

✓ Syncope = TLOC <20s with rapid complete recovery; differentiate from seizure (post-ictal confusion) and cardiac arrest (no pulse)

✓ Immediate ECG mandatory within 1 hour; red flags include QTc >450/470 ms, Brugada pattern, heart block (NICE CG109)

✓ Postural BP: measure at 0, 1, 3 minutes; positive if ≥20/10 mmHg drop

✓ Canadian Syncope Risk Score ≥3 or any NICE admission criteria → admit for monitoring

✓ Cardiac syncope warning signs: exertional, no prodrome, FH sudden death <40 years, abnormal ECG

✓ Score 0 Canadian + normal ECG + no red flags = <1% risk, safe for discharge with outpatient follow-up

✓ Common pitfall: Missing orthostatic hypotension by not waiting 3 minutes or measuring only once