❤️ Cardiovascular · ACS Risk
HEART Score
Chest pain risk stratification for ACS in the Emergency Department
H — History
Slightly suspicious
Non-specific history, limited information
+0
Moderately suspicious
Some features of ischaemia without classic presentation
+1
Highly suspicious
Classic ischaemic: pressure, radiation, exertional, diaphoresis
+2
E — ECG
Normal ECG
+0
Non-specific repolarisation disturbance
LBBB, LVH, early repolarisation, paced rhythm, ST depression <1mm
+1
Significant ST deviation
ST depression or elevation >1mm, T-wave inversion
+2
A — Age
Age < 45 years
+0
Age 45–64 years
+1
Age ≥ 65 years
+2
R — Risk Factors
No known risk factors
+0
1–2 risk factors
HTN, hypercholesterolaemia, DM, obesity BMI>30, smoking, family history
+1
≥3 risk factors OR known atherosclerotic disease
Known CAD, PCI, CABG, stroke, or peripheral arterial disease
+2
T — Troponin
≤ Normal limit
+0
1–3× normal limit
+1
>3× normal limit
+2
🔵 MRCEM Clinical Pearls
- HEART ≤3 → safe for early discharge (0.9–1.7% MACE rate)
- HEART ≥7 → early invasive strategy; cath lab referral
- Each component scored 0–2; total range 0–10
- Validated in multiple prospective ED studies
⚠️ Educational tool only. Clinical decisions must integrate full history, examination, and investigations. Not a substitute for clinical judgement.
HEART Score
0
out of 10
Risk Category
Select all five criteria
Work through H, E, A, R, T above.
Score Interpretation
Low (0–3)≤1.7% MACE
Moderate (4–6)12–16% MACE
High (7–10)50–65% MACE
🫁 Thromboembolic · PE Probability
Wells Score for PE
Pre-test probability of pulmonary embolism — guides CTPA and D-dimer decisions
Clinical Criteria
Clinical signs of DVT
Leg swelling, tenderness over deep veins
+3
PE is #1 diagnosis OR equally likely
Alternative diagnoses cannot fully explain the presentation
+3
Heart rate > 100 bpm
+1.5
Immobilisation ≥3 days OR surgery in past 4 weeks
+1.5
Previous DVT or PE
+1.5
Haemoptysis
+1
Malignancy (active or treated within 6 months)
+1
🔵 MRCEM Clinical Pearls
- Traditional: ≤4 = Low, 4–8 = Moderate, >8 = High probability
- Dichotomised: ≤4 = PE unlikely (D-dimer), >4 = PE likely (CTPA)
- Always pair with PERC if pretest probability is low
- D-dimer only useful if Wells ≤4 in dichotomised model
⚠️ Educational tool only. Not a substitute for clinical judgement.
Wells PE Score
0
out of 12.5
Probability
Select criteria above
Tick all applicable items to calculate.
Score Interpretation
Low (≤1)~1.3% PE
Moderate (2–6)~16% PE
High (≥7)~41% PE
PE unlikely (≤4)D-dimer / PERC
PE likely (>4)CTPA indicated
🩸 Thromboembolic · DVT Probability
Wells Score for DVT
Pre-test probability of deep vein thrombosis — guides duplex ultrasound and D-dimer use
Clinical Criteria
Active cancer
Treatment ongoing, within 6 months, or palliative
+1
Paralysis, paresis, or recent plaster immobilisation of lower limb
+1
Bedridden >3 days OR major surgery within 12 weeks
+1
Localised tenderness along deep venous system
+1
Entire leg swollen
+1
Calf swelling >3cm vs asymptomatic leg
Measured 10cm below tibial tuberosity
+1
Pitting oedema confined to symptomatic leg
+1
Collateral superficial veins (non-varicose)
+1
Previously documented DVT
+1
Alternative diagnosis at least as likely as DVT
Baker's cyst, cellulitis, muscle tear, superficial thrombophlebitis
−2
🔵 MRCEM Clinical Pearls
- Score ≤0: DVT unlikely — use D-dimer; if negative, DVT excluded
- Score 1–2: Moderate — proximal duplex USS
- Score ≥3: High — urgent proximal duplex USS
- Note the −2 for alternative diagnosis — common exam trap
⚠️ Educational tool only. Not a substitute for clinical judgement.
Wells DVT Score
0
out of 9
Probability
Select criteria above
Tick all applicable items to calculate.
Score Interpretation
Low (≤0)~3% DVT
Moderate (1–2)~17% DVT
High (≥3)~75% DVT
🫁 PE Exclusion · PERC Rule
PERC Rule
Pulmonary Embolism Rule-out Criteria — excludes PE without D-dimer in low-risk patients
How to use: Apply ONLY when clinical gestalt suggests LOW pretest probability of PE. If ALL eight criteria are absent (all NO), PE is excluded — no D-dimer needed.
Mark any criteria PRESENT (Yes = PERC Positive)
Age ≥ 50 years
Yes
No
Heart rate ≥ 100 bpm
Yes
No
O₂ saturation < 95% on room air
Yes
No
Unilateral leg swelling
Yes
No
Haemoptysis
Yes
No
Surgery or trauma within 4 weeks requiring GA
Yes
No
History of DVT or PE
Yes
No
Exogenous oestrogen use
Yes
No
🔵 MRCEM Clinical Pearls
- All NEGATIVE: PE excluded — no D-dimer needed in low pretest probability
- Any POSITIVE: proceed to D-dimer or Wells → CTPA pathway
- NEVER apply PERC if clinical suspicion is moderate or high
- Sensitivity 97.4%, miss rate ~1.4% in low-probability patients
- PERC is a RULE-OUT tool only — it does not diagnose PE
⚠️ Educational tool only. Not a substitute for clinical judgement.
PERC Result
NEGATIVE
All 8 criteria absent
PERC Status
PERC Negative
All 8 criteria absent. In low pretest probability, PE can be safely excluded without D-dimer.
Criteria Summary
Total criteria8
All absentPE excluded
Any presentFurther workup
🦠 Sepsis · Bedside Screening
qSOFA Score
Quick Sequential Organ Failure Assessment — rapid bedside sepsis identification
Three Bedside Criteria (1 point each)
Respiratory Rate ≥ 22 breaths/min
+1
Altered Mentation
GCS < 15 — any change in consciousness or cognition
+1
Systolic BP ≤ 100 mmHg
+1
🔵 MRCEM Clinical Pearls
- qSOFA ≥2: high risk of poor outcome with suspected infection — escalate
- Does NOT diagnose sepsis — use Sepsis-3 criteria (SOFA ≥2 from baseline)
- Bedside tool: no labs needed, assess in under 60 seconds
- Sensitivity ~70% — do not use to rule out sepsis
- If qSOFA ≥2: blood cultures, lactate, early IV antibiotics, senior review
⚠️ Educational tool only. Not a substitute for clinical judgement.
qSOFA Score
0
out of 3
Risk
Select criteria above
Tick applicable items to calculate.
Score Interpretation
Score 0–1Lower risk
Score ≥ 2High risk — act now
🫁 Respiratory · CAP Severity
CURB-65
Community-acquired pneumonia severity — guides admission vs. discharge decisions
Criteria (1 point each)
C — Confusion (new onset)
AMTS ≤8 or disorientation to person, place, or time
+1
U — Urea > 7 mmol/L (BUN > 19 mg/dL)
+1
R — Respiratory Rate ≥ 30 breaths/min
+1
B — BP: Systolic < 90 OR Diastolic ≤ 60 mmHg
+1
65 — Age ≥ 65 years
+1
🔵 MRCEM Clinical Pearls
- Score 0–1: Low — consider home treatment if no social concerns
- Score 2: Moderate — short-stay admission or close outpatient follow-up
- Score 3–5: Severe — admit; score ≥4 consider HDU/ICU
- CRB-65 (no urea needed) used in GP/community setting
- Always factor in O₂ sats, bilateral infiltrates, and social circumstances
⚠️ Educational tool only. Not a substitute for clinical judgement.
CURB-65 Score
0
out of 5
Severity
Select criteria above
Tick applicable items to calculate.
30-Day Mortality
Score 00.7%
Score 13.2%
Score 213%
Score 317%
Score 4–541.5%
🧠 Neurology · Consciousness Level
Glasgow Coma Scale (GCS)
Standardised assessment of level of consciousness — universal in emergency and critical care
E — Eye Opening (1–4)
Eye Opening4
1-None2-Pain3-Voice4-Spontaneous
V — Verbal Response (1–5)
Verbal Response5
1-None2-Sounds3-Words4-Confused5-Oriented
M — Motor Response (1–6)
Motor Response6
1-None2-Extension3-Flex4-Withdraw5-Localise6-Obeys
Motor reference: M1=None · M2=Extension (decerebrate) · M3=Flexion (decorticate) · M4=Withdrawal · M5=Localises · M6=Obeys commands
🔵 MRCEM Clinical Pearls
- GCS 3 = lowest possible (NOT zero); GCS 15 = normal
- Intubation threshold: GCS ≤8 or rapidly deteriorating — "protect airway"
- Always document as components: E4V5M6, not just "GCS 15"
- Modified (paediatric) GCS has different verbal component
- GCS not valid if intubated, sedated, or ocular trauma present
⚠️ Educational tool only. Not a substitute for clinical judgement.
GCS Total
15
E4 + V5 + M6
Mild (13–15)
GCS 15 — Normal
Fully conscious and oriented.
GCS Severity
13–15Mild
9–12Moderate
3–8Severe
≤8Airway at risk
🧠 Trauma · Head CT Decision
Canadian CT Head Rule
Identifies minor head injuries requiring CT — applies to GCS 13–15 with LOC, amnesia, or confusion
Apply only to: GCS 13–15 with witnessed LOC, amnesia, or disorientation. Exclude: age <16, anticoagulants, seizure post-injury, obvious open skull fracture.
High-Risk Factors (CT for neurosurgical intervention)
GCS score < 15 at 2 hours post-injury
High Risk
Suspected open or depressed skull fracture
High Risk
Any sign of basal skull fracture
Haemotympanum, periorbital ecchymosis, CSF otorrhoea/rhinorrhoea, Battle's sign
High Risk
Vomiting ≥ 2 episodes
High Risk
Age ≥ 65 years
High Risk
Medium-Risk Factors (CT for brain injury detection)
Amnesia before impact ≥ 30 minutes
Med Risk
Dangerous mechanism
Pedestrian struck, occupant ejected, fall >3 feet or 5 stairs
Med Risk
🔵 MRCEM Clinical Pearls
- ANY single criterion = CT head required
- ALL absent = CT not required (near 100% sensitivity for neurosurgical lesions)
- Does NOT apply if GCS <13, age <16, anticoagulated, or post-seizure
- NICE CG176 criteria slightly differ — know both for MRCEM
- Battle's sign and raccoon eyes appear 12–24h after injury
⚠️ Educational tool only. Not a substitute for clinical judgement.
CT Head Decision
NOT REQUIRED
No criteria present
Decision
CT Not Required
No Canadian CT Head Rule criteria present. CT is not indicated.
🦴 Trauma · X-Ray Decision
Ottawa Ankle Rules
Determines need for ankle and foot X-ray following acute ankle injury
Apply when: Ankle pain in malleolar zone OR mid-foot pain after acute injury. Validated in adults ≥18. Not for isolated toe injuries.
Ankle X-Ray — Pain in malleolar zone PLUS:
Tenderness: posterior edge/tip of lateral malleolus
Distal 6cm of fibula — posterior aspect
→ XR
Tenderness: posterior edge/tip of medial malleolus
Distal 6cm of tibia — posterior aspect
→ XR
Unable to weight-bear immediately AND in ED
4 steps counts — even if limping
→ XR
Foot X-Ray — Pain in mid-foot zone PLUS:
Tenderness at base of 5th metatarsal
→ XR
Tenderness over navicular bone
→ XR
Unable to weight-bear (mid-foot zone)
→ XR
🔵 MRCEM Clinical Pearls
- Sensitivity ~99–100% for clinically significant fractures
- Reduces unnecessary X-rays by 30–40% when applied correctly
- Not validated in: children <18, pregnancy, intoxication, or multiple injuries
- Posterior 6cm of fibula/tibia is the key zone — anterior rarely fractured alone
- Ottawa Knee Rules follow same principle — know both for MRCEM
⚠️ Educational tool only. Not a substitute for clinical judgement.
X-Ray Decision
NOT NEEDED
No criteria met
Ottawa Ankle Result
X-Ray Not Indicated
No Ottawa criteria met. X-ray not required per Ottawa Ankle Rules.
Rule Performance
Sensitivity~99%
Specificity~35–40%
XR reduction30–40%
🧑⚕️ Syncope · Risk Stratification
San Francisco Syncope Rule
Identifies ED syncope patients at risk of serious outcomes requiring admission
CHESS Mnemonic: If ANY single criterion is present, the patient is HIGH RISK for a serious outcome within 7 days.
CHESS Criteria — Any single criterion = High Risk
C — Congestive Heart Failure (history of)
CHESS
H — Haematocrit < 30%
CHESS
E — Abnormal ECG
New changes OR non-sinus rhythm on ED ECG
CHESS
S — Shortness of Breath
At triage or in history
CHESS
S — Systolic BP < 90 mmHg at triage
CHESS
🔵 MRCEM Clinical Pearls
- ANY positive criterion = admit or further investigation
- ALL absent = low risk → discharge with outpatient follow-up may be appropriate
- Sensitivity 96%, Specificity 62% for 7-day serious outcomes
- Serious outcomes: death, MI, arrhythmia, PE, stroke, SAH, AAA, structural heart disease
- Canadian Syncope Risk Score increasingly preferred — know both for MRCEM
⚠️ Educational tool only. Not a substitute for clinical judgement.
SF Syncope Result
LOW RISK
No CHESS criteria
Risk Category
Low Risk
No CHESS criteria present. Discharge with outpatient follow-up may be appropriate based on this rule alone.
Rule Performance
Sensitivity96%
Specificity62%
Any criterion +veHIGH risk → admit
All criteria -veLOW risk → d/c?