Collapse and syncope

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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

Figure 1: ECG showing prolonged QT interval exceeding half the RR interval

Classification by Mechanism:

TypeFrequencyKey Features
Reflex (vasovagal)60%Prodrome, triggers, young patients
Orthostatic15%Postural drop, medications, elderly
Cardiac10-15%No warning, exertional, FH sudden death
Unexplained10-15%Requires risk stratification

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

Figure 2: ECG showing coved ST elevation in V1-V2 characteristic of Type 1 Brugada pattern

🚩 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):

Risk FactorPoints
Clinical judgment predicts serious cause+2
Vasovagal features absent+1
Heart disease history+1
Systolic BP <90 or >180 mmHg+2
Elevated troponin+2
Abnormal QRS axis+1
QTc >450 ms+1
  • 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:

StepActionNormal Response
1Supine BP after 5 min restBaseline
2Stand patientMonitor symptoms
3Measure at 1 minute<10 mmHg drop
4Measure at 3 minutes<20/10 mmHg drop

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

Practice Questions: Collapse and syncope

Test your understanding with these related questions

A 55-year-old man presents with acute severe abdominal pain and hypotension. He takes warfarin for atrial fibrillation. CT shows large retroperitoneal hematoma. His INR is 7.5. What is the most appropriate immediate management?

1 of 5

Flashcards: Collapse and syncope

1/10

_____ should be given in addition to dual antiplatelet therapy in NSTEMI patients who are not at a high risk of bleeding/ having angiography immediately

TAP TO REVEAL ANSWER

_____ should be given in addition to dual antiplatelet therapy in NSTEMI patients who are not at a high risk of bleeding/ having angiography immediately

Fondaparinux

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