Suspected Pulmonary Embolism in a Young Woman with a Normal Chest X-ray
A 29-year-old woman on a combined oral contraceptive presents with 6 hours of pleuritic chest pain and breathlessness. HR 112, BP 118/72, RR 24, SpO2 94% on room air, temperature 37.2°C. Chest examination is clear; the chest X-ray is normal. She has no prior VTE, no recent surgery, no immobility and no known thrombophilia. Your ED has no CT pulmonary angiogram after 22:00; the on-call radiologist can perform a bedside echo. D-dimer is available and results in 1 hour. She is anxious and asks whether she can go home with a follow-up appointment.
1. Work through the diagnostic strategy, including the role of clinical probability, D-dimer and imaging.
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Step 1 - Estimate clinical probability. Use a validated tool (Wells or Geneva). She has clinical signs of DVT? No. PE is the most likely diagnosis? Possibly. HR >100: yes. Immobilisation/surgery: no. Previous VTE: no. Haemoptysis: no. Malignancy: no. Combined oral contraceptive use is a risk factor but is not itself a Wells item. Her score is likely in the 'PE likely' or intermediate range when gestalt is included - so a negative D-dimer may not be sufficient to exclude PE depending on the tool used.
Step 2 - D-dimer. In a young woman on oestrogen, a raised D-dimer is common and non-specific; a negative result has good negative predictive value in low/intermediate probability but is less useful if probability is high. Do not use a positive D-dimer alone to commit to lifelong anticoagulation without imaging.
Step 3 - Imaging. CTPA is the test of choice. If unavailable, options include: (a) transfer to a centre with CTPA; (b) ventilation-perfusion scanning if available; (c) bedside echo - a normal echo does not exclude PE, but RV strain changes would support the diagnosis and change management.
Step 4 - Decide. She is haemodynamically stable, so urgent thrombolysis is not indicated. If probability is high and imaging is delayed, start therapeutic anticoagulation while arranging imaging, after weighing bleeding risk. Do not discharge her on the basis of a normal chest X-ray.
2. How would the presence of right ventricular strain on bedside echo change your management, and what would you do if she became hypotensive?
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RV strain on echo (dilated RV, septal flattening, McConnell sign, raised RV pressure) in a haemodynamically stable patient identifies a submassive/intermediate-risk PE. It does not by itself mandate thrombolysis, but it mandates admission, continuous monitoring and usually therapeutic anticoagulation. Some protocols consider catheter-directed therapy or thrombolysis in selected intermediate-high-risk patients, but this requires specialist input.
If she becomes hypotensive (systolic BP <90 mmHg or a fall >40 mmHg, or shock): she becomes high-risk/massive PE. Management:
- Resuscitate: cautious fluid bolus (over-filling the RV worsens output), vasopressors (noradrenaline) for hypotension, and oxygen.
- Reperfusion: systemic thrombolysis (e.g. alteplase) is first-line if there is no contraindication; otherwise catheter-directed therapy or surgical embolectomy where available.
- Avoid positive-pressure ventilation where possible, or use low tidal volumes and cautious pressures, because it reduces venous return.
- Anticoagulate with unfractionated heparin if thrombolysis is planned.
- Escalate: activate the transfer pathway to a centre with reperfusion capability.
3. She asks whether she can go home. Justify your disposition decision and the safety-netting you would give.
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She should not be discharged from the ED.
- PE has not been excluded, and she has symptoms, tachycardia and hypoxia at the lower limit of normal. The risk of a missed PE, with potential progression to haemodynamic collapse, outweighs the inconvenience of admission.
- If imaging is negative and an alternative diagnosis is established, outpatient management could be considered in a low-risk patient using a validated tool (e.g. sPESI) and only where follow-up and anticoagulation can be assured.
- Disposition: admit for monitoring, oxygen if needed, anticoagulation if imaging is delayed and probability is high, and arrange definitive imaging.
Safety-netting if she is discharged after a negative work-up: return immediately for worsening breathlessness, syncope, chest pain, haemoptysis or leg swelling; ensure she knows to report new symptoms; arrange early review; and document the residual diagnostic uncertainty and the plan.