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Pulmonary embolism
In pulmonary embolism you start with the clinical probability (Wells or Geneva), use D-dimer only when probability is not high, confirm with CT angiography, and choose treatment by haemodynamic stability: a patient in shock — thrombolysis; a stable patient — anticoagulation.
Why it matters in the exam
Questions test the order of the work-up: a negative D-dimer excludes embolism only at low or intermediate probability (and above age 50 an age-adjusted cut-off is used: age multiplied by 10); at high probability go straight to CT. When contrast cannot be used — a ventilation–perfusion scan. In an unstable patient who cannot be taken to CT, a bedside echo showing right-ventricular strain is enough to start treatment.
The choice of anticoagulant by situation is asked: a DOAC in most patients; LMWH in pregnancy (no DOAC and no warfarin); warfarin in antiphospholipid syndrome, especially with three positive antibodies; and in HIT — stop heparin and switch to a non-heparin anticoagulant. Duration: 3 months when the provoking factor is transient (surgery), extended when there is no provoking factor, and as long as cancer is active. A vena cava filter only when anticoagulation is absolutely contraindicated. With breathlessness lasting beyond 3 months after an embolism — think of CTEPH and perform a scan.
Case questions often feature a patient after orthopaedic surgery, a pregnant or post-partum woman, and a patient with cancer. The most common ECG finding is sinus tachycardia; the S1Q3T3 pattern is typical but rare.
Key points
- The order: stability, clinical probability, D-dimer (only when probability is not high), CT angiography.
- Unstable: thrombolysis; stable: anticoagulation.
- A DOAC in most patients; LMWH in pregnancy; warfarin in antiphospholipid syndrome.
- Duration: 3 months with a transient factor; extended when unprovoked; as long as cancer is active.
- Breathlessness beyond 3 months after embolism — think of CTEPH.
Summary table
| Risk level | Definition | Treatment | Note |
|---|---|---|---|
| High risk | Shock or systolic below 90 | Thrombolysis (alteplase 100 mg over 2 hours) and heparin | If thrombolysis is contraindicated — catheter or surgical embolectomy |
| Intermediate-high | Stable, with right-ventricular strain and raised troponin | Anticoagulation and close monitoring | Rescue thrombolysis if deteriorating |
| Intermediate-low | Stable, with at most one of the two | Anticoagulation in hospital | — |
| Low risk | sPESI of 0 | Anticoagulation, early discharge possible | — |
| Choice of anticoagulant | DOAC in most patients | LMWH in pregnancy; warfarin in antiphospholipid syndrome | In HIT — no heparin |
| Duration | 3 months with a transient factor | Extended for unprovoked embolism; as long as cancer is active | Vena cava filter only when anticoagulation is forbidden |
A free exam question
בן 35 ,ללא רקע רפואי, מתאשפז בשל קוצר נשימה מלווה בכאב פלאוריטי המאובחן כתסחיף ריאתי, וכיב ברגל. בנוסף, יש אי ספיקת כליות חדה. במעבדה: אנטי קרדיוליפין ו- 2 GPI בכייל גבוה של IgG ו- IgM ., וגם לופוס אנטי קואגולנט החולה מטופל בסטרואידים ופלסמהפרזיס. מה הטיפו?ל הנוסף המומלץ (the question as examined, in Hebrew)
- א. Warfarin + Cyclophosphamide
- ב. LMWH + IVIg
- ג. LMWH + Hydroxychloroquine
- ד. Rivaroxban + IVIg
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
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Sources
- ESC Guidelines for the diagnosis and management of acute pulmonary embolism, 2019 — Diagnostic strategy, risk stratification, anticoagulation and reperfusion
- Harrison's Principles of Internal Medicine, 21st edition (2022) — Deep Venous Thrombosis and Pulmonary Thromboembolism
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.