Recognise / red flags: Suspect PE with otherwise unexplained breathlessness, pleuritic chest pain, syncope, haemoptysis or signs of DVT; hypotension or shock implies high-risk PE and demands urgent senior support.
Investigate / stratify: For stable adults use the two-level Wells score and D-dimer where PE is unlikely; for PE likely obtain CTPA urgently (V/Q alternative if appropriate). If imaging is delayed, consider interim therapeutic anticoagulation after assessing contraindications.
Initial management: Confirmed PE usually requires at least 3 months of anticoagulation. In PE with haemodynamic instability, NICE recommends continuous IV unfractionated heparin and consideration of systemic thrombolysis; do not routinely thrombolyse haemodynamically stable PE even with RV dysfunction.
Exam pitfall / safety: In pregnancy, compression leg ultrasound is useful when DVT symptoms/signs exist, but is not a mandatory first test for every suspected PE. Use an obstetric specialist imaging pathway and avoid applying non-pregnant Wells pathways uncritically.

Source checked 2026-10-30: NICE NG158 / RCOG pregnancy information. Focused teaching summary only; historical material below has not had a full dose-by-dose review. Use current BNF, local guidelines and specialist advice for individual patients.

🫁 Pulmonary emboli should be prevented by early mobilisation and low-dose LMWH in all at-risk patients. ⚠️ Untreated mortality is ~30%, which falls to ~8% with treatment.

⚕️ Stepwise Management of Suspected PE NICE NG158 aligned
🧮 Clinical suspicion → Calculate Wells Score 🔎 Wells ≤ 4 (PE unlikely): Check D-dimer 🟢 If negative → Exclude PE, look for alternative cause 🔴 If positive → Order CTPA → Treat if confirmed ⚠️ Wells > 4 (PE likely): Do not check D-dimer Request CTPA directly → Treat if positive 💉 If CTPA delayed → Start interim therapeutic anticoagulation 🤰 Pregnancy → Use a specialist obstetric PE pathway. Compression leg ultrasound is appropriate when there are symptoms/signs of DVT; V/Q scanning or CTPA may still be needed. 🚨 Massive PE (shock/arrest) → Thrombolyse Alteplase: 10 mg IV bolus + 90 mg over 2h If cardiac arrest → full bolus + CPR 60–90 min 🟠 Haemodynamically stable PE with RV strain → NICE advises against systemic thrombolysis; monitor and escalate promptly if haemodynamic instability develops. ⛔ Contraindication to anticoagulation → Consider IVC filter 💊 Routine therapy → LMWH, UFH, Apixaban, Rivaroxaban (per local protocol/NICE)

⚕️ Stepwise Management of Suspected PE NICE NG158 aligned

🧮 Clinical suspicion → Calculate Wells Score
🔎 Wells ≤ 4 (PE unlikely):
- Check D-dimer
- 🟢 If negative → Exclude PE, look for alternative cause
- 🔴 If positive → Order CTPA → Treat if confirmed
⚠️ Wells > 4 (PE likely):
- Do not check D-dimer
- Request CTPA directly → Treat if positive
💉 If CTPA delayed → Start interim therapeutic anticoagulation
🤰 Pregnancy → Use a specialist obstetric PE pathway. Compression leg ultrasound is appropriate when there are symptoms/signs of DVT; V/Q scanning or CTPA may still be needed.
🚨 Massive PE (shock/arrest) → Thrombolyse
- Alteplase: 10 mg IV bolus + 90 mg over 2h
- If cardiac arrest → full bolus + CPR 60–90 min
🟠 Haemodynamically stable PE with RV strain → NICE advises against systemic thrombolysis; monitor and escalate promptly if haemodynamic instability develops.
⛔ Contraindication to anticoagulation → Consider IVC filter
💊 Routine therapy → LMWH, UFH, Apixaban, Rivaroxaban (per local protocol/NICE)

Pulmonary embolism is obstruction of the pulmonary arterial circulation, usually from thrombus arising in deep veins of the legs or pelvis. Untreated mortality approaches 25–30%, falling to <8% with anticoagulation. Early diagnosis, appropriate risk stratification, and prompt treatment are lifesaving.

🧬 Causes & Risk Factors (Virchow’s Triad)

Venous stasis: immobility, long-haul travel, hospitalisation, paralysis, heart failure.
Endothelial injury: surgery (especially orthopaedic), trauma, central venous lines.
Hypercoagulability:
- Active cancer (pancreas, lung, gastric, brain, haematological highest risk).
- Pregnancy & postpartum (highest risk first 6 weeks postpartum).
- Oestrogen therapy (OCP, HRT).
- Inherited thrombophilia (Factor V Leiden, Prothrombin gene mutation, Protein C/S deficiency, Antithrombin deficiency).
- Antiphospholipid syndrome.
- Obesity, smoking.
Other causes of embolic obstruction: fat embolism (fracture), amniotic fluid embolism, air embolism, tumour emboli (rare).

🧠 Pathophysiology

Acute embolic obstruction increases pulmonary vascular resistance, causing right ventricular (RV) pressure overload. The thin-walled RV dilates, impairing left ventricular preload and cardiac output. Hypoxaemia results from ventilation–perfusion mismatch and reduced mixed venous oxygen. Large PE may cause obstructive shock and sudden death.

🩺 Clinical Presentation

Dyspnoea (most common).
Pleuritic chest pain.
Tachycardia, tachypnoea.
Haemoptysis (infarction).
Syncope or presyncope (suggests massive PE).
Signs of DVT: unilateral leg swelling, calf tenderness.
Massive PE: hypotension, raised JVP, loud P2, shock.

🧮 Diagnosis - Stepwise Approach (Adults, Non-Pregnant)

🫁 ASSESS WITH WELLS or GENEVA score

🧮 Wells and Geneva Score Components

In UK practice (NICE NG158), Wells score is most commonly used. Geneva may be useful where an entirely objective score is preferred.

🧮 Wells Score (UK NICE Preferred)	📋 Revised Geneva Score (Objective)
Score Components Clinical signs of DVT → +3 PE most likely diagnosis → +3 HR >100 bpm → +1.5 Immobilisation ≥3 days or surgery <4 weeks → +1.5 Previous DVT/PE → +1.5 Haemoptysis → +1 Active cancer → +1 Interpretation >4 → PE likely → CTPA immediately ≤4 → PE unlikely → Perform D-dimer Use age-adjusted D-dimer if >50 years (Age × 10 micrograms/L FEU) If D-dimer negative → PE excluded If D-dimer positive → CTPA If imaging delayed >4 hours in likely cases → Start interim anticoagulation	Score Components Age ≥65 years → +1 Previous DVT/PE → +3 Surgery or fracture within 1 month → +2 Active malignancy → +2 Unilateral lower limb pain → +3 Haemoptysis → +2 Heart rate 75–94 bpm → +3 Heart rate ≥95 bpm → +5 Pain on deep venous palpation and unilateral oedema → +4 Interpretation 0–3 → Low probability 4–10 → Intermediate probability ≥11 → High probability Low / Intermediate → Perform D-dimer D-dimer negative → PE excluded D-dimer positive → CTPA High probability → CTPA immediately (no D-dimer) If imaging delayed >4 hours → Start interim anticoagulation Geneva is fully objective and avoids clinician judgement bias.

🧮 Wells Score (UK NICE Preferred)

📋 Revised Geneva Score (Objective)

Score Components

Clinical signs of DVT → +3
PE most likely diagnosis → +3
HR >100 bpm → +1.5
Immobilisation ≥3 days or surgery <4 weeks → +1.5
Previous DVT/PE → +1.5
Haemoptysis → +1
Active cancer → +1

Interpretation

>4 → PE likely → CTPA immediately
≤4 → PE unlikely → Perform D-dimer
Use age-adjusted D-dimer if >50 years (Age × 10 micrograms/L FEU)
If D-dimer negative → PE excluded
If D-dimer positive → CTPA
If imaging delayed >4 hours in likely cases → Start interim anticoagulation

Score Components

Age ≥65 years → +1
Previous DVT/PE → +3
Surgery or fracture within 1 month → +2
Active malignancy → +2
Unilateral lower limb pain → +3
Haemoptysis → +2
Heart rate 75–94 bpm → +3
Heart rate ≥95 bpm → +5
Pain on deep venous palpation and unilateral oedema → +4

Interpretation

0–3 → Low probability
4–10 → Intermediate probability
≥11 → High probability
Low / Intermediate → Perform D-dimer
D-dimer negative → PE excluded
D-dimer positive → CTPA
High probability → CTPA immediately (no D-dimer)
If imaging delayed >4 hours → Start interim anticoagulation

Geneva is fully objective and avoids clinician judgement bias.

🧠 Practical Teaching Point

Wells is NICE-recommended and most used in UK practice.
Geneva is helpful when an entirely objective system is preferred.
Haemodynamic instability overrides both - treat as massive PE immediately.

🔬 Investigations & Interpretation

D-dimer: High sensitivity, low specificity. Elevated in infection, malignancy, pregnancy, elderly. Adjust normal expected levels to the patient age. Don't use in pregnancy is current advice. Some may find a normal dimer in pregnancy to be useful
ABG: Type 1 respiratory failure (low O₂, low/normal CO₂).
ECG: Sinus tachycardia most common. Possible RV strain (S1Q3T3, RBBB, T-wave inversion V1–V4).
Troponin/BNP: Elevated in RV strain; prognostic marker.
Chest X-ray: Often normal; may show effusion, wedge infarct. Can be done even if pregnant
Doppler USS lower limb: Useful if pregnant and signs of DVT
CTPA: First-line imaging; visualises intraluminal filling defects.
V/Q scan: Useful in pregnancy or contrast allergy; mismatch suggests PE.
Echocardiography: Reasonable if too unwell for CTPA to look for RV dilatation, septal flattening in massive/submassive PE to help judge need for Alteplase.
Compression ultrasound: Proximal DVT → treat as PE equivalent.

Pulmonary artery anatomy

CT Pulmonary artery

🖥️ CT Pulmonary Angiography (CTPA) |CTPA In PE

🫁 PE CONFIRMED: WHAT IS RISK OF DISCHARGE WITH PESI SCORE

⚡ Risk Stratification After Confirmation

Massive (high-risk): SBP <90 mmHg or shock.
Intermediate-risk: RV strain but normotensive.
Low-risk: Haemodynamically stable, no RV strain.
Use PESI or simplified PESI for prognostic assessment and outpatient suitability.

📊 Pulmonary Embolism Severity Index (PESI) & Simplified PESI

📋 Full PESI Score	🩺 Simplified PESI (sPESI)
Variables & Points Age → +1 per year Male sex → +10 Active cancer → +30 Heart failure → +10 Chronic lung disease → +10 Pulse ≥110 bpm → +20 Systolic BP <100 mmHg → +30 Respiratory rate ≥30/min → +20 Temperature <36°C → +20 Altered mental status → +60 O₂ saturation <90% → +20 Risk Classes Class I (≤65) → ~1% mortality Class II (66–85) → ~3% Class III (86–105) → ~6% Class IV (106–125) → ~10% Class V (>125) → ~25%	Variables (1 point each) Age >80 years Active cancer Chronic cardiopulmonary disease Pulse ≥110 bpm Systolic BP <100 mmHg O₂ saturation <90% Interpretation sPESI = 0 → Low risk (~1%) → Consider outpatient management if safe sPESI ≥1 → Higher risk → Admit for monitoring

📋 Full PESI Score

🩺 Simplified PESI (sPESI)

Variables & Points

Age → +1 per year
Male sex → +10
Active cancer → +30
Heart failure → +10
Chronic lung disease → +10
Pulse ≥110 bpm → +20
Systolic BP <100 mmHg → +30
Respiratory rate ≥30/min → +20
Temperature <36°C → +20
Altered mental status → +60
O₂ saturation <90% → +20

Risk Classes

Class I (≤65) → ~1% mortality
Class II (66–85) → ~3%
Class III (86–105) → ~6%
Class IV (106–125) → ~10%
Class V (>125) → ~25%

Variables (1 point each)

Age >80 years
Active cancer
Chronic cardiopulmonary disease
Pulse ≥110 bpm
Systolic BP <100 mmHg
O₂ saturation <90%

Interpretation

sPESI = 0 → Low risk (~1%) → Consider outpatient management if safe
sPESI ≥1 → Higher risk → Admit for monitoring

🧠 Teaching Pearls

Wells / Geneva: Diagnostic tools (before imaging).
PESI / sPESI: Prognostic tools (after PE confirmed).
Haemodynamic instability overrides scoring systems - treat immediately.
Outpatient PE management requires low PESI/sPESI, stable vitals, and good social support.

🫁 NOW CONTINUE TO TREAT CONFIRMED PE

💊 Management - General Principles

Oxygen if hypoxic.
Immediate therapeutic anticoagulation if PE suspected and imaging delayed.
First-line anticoagulation: DOAC (Apixaban or Rivaroxaban).

Apixaban 10 mg twice daily for 7 days. Then 5 mg twice daily. Extended prevention (after 6 months): 2.5 mg twice daily
Rivaroxaban 15 mg twice daily for 21 days. Then 20 mg once daily. Extended prevention: 10 mg once daily (if low recurrence risk)
Avoid DOACs in severe renal impairment (CrCl <15 mL/min), pregnancy, mechanical heart valves, and triple-positive antiphospholipid syndrome.

Low Molecular Weight Heparin (LMWH)
- Preferred in pregnancy and sometimes in active cancer or high bleeding risk.
- Enoxaparin 1 mg/kg twice daily OR 1.5 mg/kg once daily (selected patients)
- Dalteparin 200 units/kg once daily (max 18,000 units daily) After 1 month: 150 units/kg once daily (cancer pathway)
- Reduce dose in renal impairment (CrCl <30 mL/min).
Unfractionated Heparin (UFH)
- Use in severe renal impairment, high bleeding risk, or when rapid reversal may be needed (short half-life).
- IV bolus: 80 units/kg
- Then infusion: 18 units/kg/hour
- Adjust to APTT target (1.5–2.5× control)
Warfarin
- Used if DOAC contraindicated (e.g., severe renal failure, antiphospholipid syndrome).
- Start 5 mg once daily (lower if elderly/frail)
- Overlap with LMWH for at least 5 days AND until INR 2–3 for 24 hours
- Target INR: 2.5 (range 2.0–3.0)
Thrombolysis
- Large/Massive PE with Shock supported by CTPA or Echocardiogram ideally. RV dysfunction on echo, refractory hypoxia, raised troponin, extreme tachycardia, large clot burden, extreme tachycardia are all factors that might support alteplase. Take senior advice if unsure. Give Alteplase 10 mg IV bolus Then 90 mg over 2 hours (max total 100 mg) Indicated in PE with haemodynamic instability (SBP <90 mmHg or shock). The contraindication is any major bleeding risk - discuss with senior decision required. Cautious IV fluids (avoid RV overload). Vasopressors if shock. Consider catheter-directed therapy or surgical embolectomy if thrombolysis contraindicated or fails.
- Cardiac Arrest Suspected PE: Alteplase 50 mg IV bolus. Continue CPR for 60–90 minutes. Consider bedside echocardiography.
- Endovascular approach Talk to interventional radiology or cardiology whatever you might have locally if unable to use thrombolysis or failing to improve with thrombolysis
- ECMO may be considered for some cases. Discuss with ITU
Duration of Treatmemt
- Provoked PE → 3 months treatment.
- Unprovoked PE → At least 3 months; consider extended therapy.
Active cancer → DOAC preferred unless high bleeding risk.
IVC filter only if anticoagulation contraindicated.

💊 Pulmonary Embolism (UK practice, NICE NG158 aligned)

Always check renal function, weight, bleeding risk, and drug interactions before prescribing. Doses below are standard adult doses - adjust in renal impairment, extremes of body weight, or frailty.

📌 Duration of Anticoagulation

Provoked PE (surgery, transient risk factor) → 3 months
Unprovoked PE → At least 3 months, reassess for extended therapy
Recurrent PE → Long-term anticoagulation
Cancer-associated → ≥6 months, often ongoing

🛑 Inferior Vena Cava (IVC) Filter

Indication: Absolute contraindication to anticoagulation OR recurrent PE despite treatment
Use retrievable filter where possible
Remove once anticoagulation safe

🧠 Practical Prescribing Pearls

Check renal function before DOAC or LMWH.
Review weight - obesity may require dosing adjustment.
Assess bleeding risk (HAS-BLED factors).
Review interacting drugs (azoles, antiepileptics, rifampicin).
Reassess need for anticoagulation at 3 months.

👵 Older Adults

Higher baseline D-dimer - use age-adjusted thresholds.
Higher bleeding risk - careful DOAC selection and renal dosing.
Consider malignancy screen in unprovoked PE.

🔎 Unprovoked PE - Further Workup

History and examination for malignancy.
Basic blood tests (FBC, LFT, calcium).
Age-appropriate cancer screening.
Thrombophilia testing only if young (<50), recurrent, unusual site, or strong family history.

📌 Duration of Anticoagulation Summary

Major transient risk factor → 3 months.
Unprovoked → 3 months then reassess; consider long-term.
Recurrent VTE → Long-term anticoagulation.
Cancer-associated → ≥6 months; usually ongoing while cancer active.

🧠 Key Clinical Pearls

Always risk stratify haemodynamic status first - shock = thrombolysis pathway.
Never delay anticoagulation in high clinical suspicion.
Pregnancy and cancer require tailored anticoagulation strategies.
Age-adjust D-dimer in patients >50 years.
Reassess bleeding risk at 3 months before stopping therapy.

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Pulmonary Embolism 🫁

Pulmonary embolism — haemodynamics come first

🧬 Causes & Risk Factors (Virchow’s Triad)

🧠 Pathophysiology

🩺 Clinical Presentation

🧮 Diagnosis - Stepwise Approach (Adults, Non-Pregnant)

🧮 Wells and Geneva Score Components

Interpretation

Interpretation

🧠 Practical Teaching Point

🔬 Investigations & Interpretation

Pulmonary artery anatomy

CT Pulmonary artery

🖥️ CT Pulmonary Angiography (CTPA) |CTPA In PE

⚡ Risk Stratification After Confirmation

📊 Pulmonary Embolism Severity Index (PESI) & Simplified PESI

🧠 Teaching Pearls

💊 Management - General Principles

💊 Pulmonary Embolism (UK practice, NICE NG158 aligned)

📌 Duration of Anticoagulation

🛑 Inferior Vena Cava (IVC) Filter

🧠 Practical Prescribing Pearls

👵 Older Adults

🔎 Unprovoked PE - Further Workup

📌 Duration of Anticoagulation Summary

🧠 Key Clinical Pearls

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