History and exam
Key diagnostic factors
common
dyspnoea
Dyspnoea is the most common presenting symptom and is seen in 50% of patients with PE.[67][76]
May be acute and severe in central PE but is often mild and may be transient in small peripheral PE.[67]
Worsening dyspnoea may be the only symptom in patients with pre-existing heart failure or pulmonary disease.[67]
Tachypnoea (respiratory rate ≥20 breaths per minute) is a common presenting sign in patients with acute PE (21% to 39%).[4]
Symptoms of PE usually come on acutely rather than gradually.
chest pain
Pleuritic chest pain is most common and seen at presentation in 39% of patients with PE.[67][76]
The pain is normally localised to one side of the chest and is unlikely to be central. This is usually caused by pleural irritation due to distal emboli causing pulmonary infarction.[81]
Normally acute onset.
Central PE may also present with angina-like chest pain but this is uncommon.[67]
This possibly reflects right ventricular ischaemia and requires differential diagnosis with acute coronary syndrome or aortic dissection.[67]
Practical tip
Do not use chest pain on palpation of the chest wall to distinguish musculoskeletal chest pain from PE.[91]
This sign is present in 20% of people with PE.
signs of concurrent deep vein thrombosis (DVT)
risk factors
Your history should check for the following risk factors to help assess the likelihood of PE and to determine whether any subsequently confirmed PE is provoked or unprovoked:[34][60][66][67][76]
No provoking cause can be found in 30% of patients.[67]
Strong risk factors | Weak risk factors | |
|---|---|---|
| Past medical history | Active cancer
Recent surgery or hospitalisation (last 3 months)
Previous or current DVT
Pregnancy and 6 weeks postpartum[34][67][78]
| Other significant medical comorbidities
Obesity
Increasing age Varicose veins Known thrombophilias
Other
|
| Social history | History of immobilisation
| Long-distance travel Smoking |
| Drug history | Combined oral contraceptive pill
Hormone replacement therapy[76]
| |
| Family history | First-degree relative with a history of confirmed PE or DVT[76] |
hypoxaemia
Oxygen saturations <94% (or <88% in patients at risk of hypercapnic respiratory failure).
However, up to 40% of patients have normal arterial oxygen saturation and 20% have a normal alveolar-arterial oxygen gradient.[67] [ A-a Gradient Opens in new window ]
The patient may be hypoxic at rest if a massive PE is present or only on exertion with a smaller PE.
failure to meet Pulmonary Embolism Rule-out Criteria (the PERC rule)
If you have a low clinical suspicion of PE, use the PERC rule.[76]
No further investigation is indicated if a patient meets the PERC rule (a PE can effectively be ruled out). The risk of PE is considered to be lower than the risk of testing.[74]
Request D-dimer testing for any patient in whom the PERC rule fails to rule out a PE (i.e., one or more criteria not fulfilled).[95]
The PERC rule is:[96]
Age <50 years
Heart rate <100 bpm
SaO 2 on room air ≥95%
No unilateral leg swelling
No haemoptysis
No recent surgery or trauma (≤4 weeks ago requiring treatment with general anaesthesia)
No prior PE or DVT
No hormone use (oral contraceptives, hormone replacement, or oestrogenic hormones used in male or female patients).
Evidence: The PERC rule
Use of the PERC rule can help prevent over-investigation when clinical suspicion of PE is low.
The UK National Institute for Health and Care Excellence (NICE) recommends considering using the PERC rule to determine whether any further investigations are required where there is a low clinical suspicion of PE (based on history, examination, and initial investigations such as ECG and chest x-ray) and other diagnoses are feasible. This recommendation is based on a 2020 NICE evidence review that assessed the diagnostic accuracy of the PERC rule.[97]
The evidence review included 7 studies (1 large cluster randomised controlled trial [RCT; people with very low pre-test probability of PE, n=1916] and 6 diagnostic accuracy studies [n=5690]).
All of the diagnostic accuracy studies were prospective cohorts; however, the performance of the PERC rule was often assessed retrospectively in these studies.
The evidence was of low to very low quality as assessed by GRADE due to lack of blinding of assessors (in some of the diagnostic accuracy studies) and of clinicians (in the RCT). There was also high heterogeneity in the diagnostic accuracy studies and very serious imprecision (due to very low event rates in both groups) in the RCT.
Meta-analysis of the diagnostic test accuracy studies found that a negative PERC rule result was indicative of a moderate decrease in the probability that someone with clinically suspected PE had a confirmed PE (negative likelihood ratio = 0.21 [95% CI 0.14 to 0.30]). The sensitivity of PERC was 0.95 (95% CI 0.91 to 0.98) and the specificity was 0.23 (95% CI 0.12 to 0.37).
A sensitivity analysis, excluding the two diagnostic accuracy studies at high risk of bias, had very similar results.
The cluster RCT found no difference in mortality, diagnostic strategy failure, and major bleeding events when PERC was used at the start of the diagnostic pathway to rule out PE compared with when it was not. The median length of emergency department stay was significantly shorter with the PERC rule (median difference 37 minutes shorter, interquartile range 4 minutes to 68 minutes shorter).
The results above, along with evidence from the guideline economic model, supported a weak recommendation to consider using the PERC rule when there is a low clinical suspicion of PE to decide which low-risk patients would benefit from further testing.
The guideline committee agreed that, based on the populations in the included studies, a low risk of PE could be defined as an estimated probability of PE <15% based on clinical assessment and the possibility of an alternative diagnosis.
Patients with intermediate or high risk of PE do not require application of the PERC rule as the result will not influence the need for further tests.
positive Wells (or Geneva) score
If you have a high clinical suspicion of PE or the patient does not meet the PERC rule, use the Wells (or Geneva) score to assess the likelihood of a PE in any non-pregnant patient who is haemodynamically stable.[67][76][77] [ Pulmonary Embolism Wells Score Opens in new window ] [ Revised Geneva Score for Estimation of the Clinical Probability of Pulmonary Embolism in Adults Opens in new window ]
The Wells score is commonly used in the UK but an alternative called the Geneva score is also available. Choose which score to use based on local protocols.
This will categorise the patient into either ‘PE likely’ (Wells score >4) or ‘PE unlikely’ (Wells score ≤4).[67][76][77]
It can also be used to guide the need for further investigations.
If a patient has a ‘PE likely’ Wells (or Geneva) score, start anticoagulation then arrange investigation with definitive imaging (usually computed tomographic pulmonary angiography [CTPA] if available).
If a patient has a ‘PE unlikely’ Wells (or Geneva) score, order a D-dimer unless the patient fulfils all the Pulmonary Embolism Rule-Out Criteria (in which case a PE can be effectively ruled out and no further investigations are indicated).[67][74][76]
If the D-dimer result cannot be obtained within 4 hours, offer anticoagulation (unless contraindicated).[76]
Criterion | Wells score points |
|---|---|
Clinical signs of DVT (minimum of leg swelling and pain with palpation of deep veins) | 3 |
Alternative diagnosis is less likely than PE | 3 |
Previous PE or DVT | 1.5 |
Heart rate >100 bpm | 1.5 |
Surgery (last 4 weeks) or immobilisation for >3 days | 1.5 |
Haemoptysis | 1 |
Active cancer | 1 |
Do not use Wells or Geneva scores in pregnancy.
If the patient is pregnant:
Seek advice from a senior clinician
PE can be ruled out in around 30% of patients who present to the emergency department with a suspected PE through a combination of clinical probability assessment using the Wells (or Geneva) score, plus D-dimer testing if indicated.[67]
This probability-based approach minimises the unnecessary use of potentially harmful CTPA in patients who have a low probability of a PE.[94]
Evidence: Wells versus Geneva scores
Wells and Geneva scores have similar sensitivity and specificity.
In a systematic review PE was confirmed in 12% of patients classified as ‘PE unlikely’ and in 50% of patients classified as ‘PE likely’.[99]
Neither one of Wells or Geneva score has been shown to be superior to the other. However, the Geneva score is based solely on objective clinical terms and may be more reproducible whereas Wells includes a subjective judgement of whether an alternative diagnosis is less likely than PE.[67]
Sensitivity of the Wells and Geneva scores ranged from 88% to 96% and specificity from 48% to 53% when each clinical decision tool was validated in a primary care dataset.[100]
uncommon
signs of haemodynamic instability or severely reduced haemodynamic reserve
Assess for signs of haemodynamic instability (ABCDE approach) as this can indicate a high-risk massive/central PE.[67]
Seek senior support and escalate to critical care if you suspect a high-risk PE.[67][74]
Haemodynamic instability in PE is defined as at least one of the following at presentation:[67]
Cardiac arrest; need for cardiopulmonary resuscitation
Obstructive shock; systolic blood pressure <90 mmHg or vasopressors required to achieve a BP ≥90 mmHg despite adequate filling status AND end-organ hypoperfusion (altered mental status; cold, clammy skin; oliguria/anuria; increased serum lactate)[67][76]
Persistent hypotension; systolic blood pressure <90 mmHg or systolic blood pressure drop ≥40 mmHg, lasting longer than 15 minutes and not caused by new-onset arrhythmia, hypovolaemia, or sepsis.
Around 5% of patients with PE are haemodynamically unstable at presentation.[92]
Check for:
Tachycardia - Heart rate >100 bpm
Tachycardia is an important sign of a possible high-risk PE even in the absence of other signs of shock.
Acute right ventricular dysfunction
Look for an elevated jugular venous pressure, parasternal heave, or accentuated pulmonary component of S2, although this is uncommon.[93]
Syncope or pre-syncope
Present in 6% of patients with PE.[67]
Other diagnostic factors
common
cough
Present in 23% of patients with PE.[67]
On auscultation of the lungs you may hear crepitations.
uncommon
fever
haemoptysis
Present in 8% of patients with PE.[76]
Distinguish true haemoptysis from bleeding arising from elsewhere.
It is commonly estimated that around half of patients presenting with haemoptysis do not have true haemoptysis. It is vital to take a clear and thorough history and examination to distinguish this.
Bleeding presenting as haemoptysis can arise from the gastrointestinal tract, upper airways, gingiva, or from epistaxis.
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