Pulmonary Embolism

Pulmonary embolism is a relatively common condition that needs to be excluded with confidence due to its’ significant associated mortality if undiagnosed. Unfortunately, the history is variable, and there are no common diagnostic findings on examination, ECG or CXR. However, these findings, considered in association with historical risk factors for venous thromboembolic disorders, will allow the emergency physician to confidently ascribe the patient to a “likely” or “unlikely” risk category (two level PE Wells score is endorsed by NICE- see Table 12)(9).

Table 12: Two-level PE Wells score(9)

Clinical feature Points
Clinical signs and symptoms of DVT (minimum of leg swelling and pain with palpation of the deep veins) 3
An alternative diagnosis is less likely than PE 3
Heart rate > 100 beats per minute 1.5
Immobilisation for more than 3 days or surgery in the previous 4 weeks 1.5
Previous DVT/PE 1.5
Haemoptysis 1
Malignancy (on treatment, treated in the last 6 months, or palliative) 1
Clinical probability simplified scores
PE likely More than 4 points
PE unlikely 4 points or less

Without further investigation, however, patients at low risk cannot be confidently reassured and discharged, and those at high risk should not be committed to prolonged anticoagulation. For patients at low risk, the diagnosis can be confidently excluded with a negative D-dimer assay(9,10,21). For patients at intermediate or high risk the diagnosis can be confidently confirmed or excluded with a ventilation perfusion (V/Q) scan or CT pulmonary angiogram (CTPA)(9,10,21).

Learning Bite

Pulmonary embolism will rarely be definitively diagnosed without ancillary investigations (D-Dimer, V/Q scan, or CTPA)