Pulmonary Embolism

Summary: <br> Introduction<br> <br> <br> <br> Pulmonary embolism (PE) is caused when a deep venous thrombosis from somewhere else in the body “embolizes” and becomes lodged in the pulmonary arteries<br> <br> <br> <br> Can cause pulmonary infarction (which mimics pneumonia on chest x-ray)<br> <br> <br> <br> Basic Approach to the Diagnosis of PE<br> <br> <br> <br> * Step 1: Consider PE in any patient with signs or symptoms consistent with the disease* Common signs/symptoms* Shortness of breath* Chest pain* Syncope* Tachycardia* Hypoxemia* Hypotension* Step 2: Do not do additional testing for PE in patients with a CLEAR alternative diagnosis* Common alternative diagnoses* COPD exacerbation* Acute coronary syndrome* Pneumonia* Keep in mind that these diagnoses are also the most frequent misdiagnoses in cases of missed PE!!! Be careful.* Step 3: Calculate Wells Score and PERC criteria* Wells score* (I personally use <a href="https://www.mdcalc.com/wells-criteria-pulmonary-embolism">Wells’ Criteria for PE by MDCalc</a>)* Define patient as either “Low” “Medium” or “High” risk* PERC criteria* I use the <a href="https://www.mdcalc.com/perc-rule-pulmonary-embolism">PERC Rule for PE by MDCalc</a> for this as well* If patient is both low risk wells and meets all PERC criteria…* No additional testing needed!!!* Step 4: Get a D-Dimer* IF… * Low risk Wells but fails PERC criteria* Medium risk Wells score* Step 5: Get a CTA* IF…* Wells score is high* Elevated d-dimer* (Update: it is now established that you can safely use AGE ADJUSTED D-DIMER)* ACEP’s clinical policy supporting this can be found <a href="https://www.acep.org/patient-care/clinical-policies/acute-venous-thromboembolic-disease/">HERE</a><br> <br> <br> <br> Final Thoughts<br> <br> <br> <br> * Bilateral lower extremity ultrasounds not sensitive enough to rule out PE* The classic EKG finding is S1Q3T3<br> <br> <br> <br> Additional Reading<br> <br> <br> <br> * Emergency Evaluation of PE: Diagnosis <a href="https://www.sciencedirect.com/science/article/abs/pii/S0736467914014292">(Journal of Emergency Medicine)</a>* Wells Criteria <a href="https://www.mdcalc.com/wells-criteria-pulmonary-embolism">(MDCalc)</a>* PERC Criteria <a href="https://www.mdcalc.com/perc-rule-pulmonary-embolism">(MDCalc)</a>* Age Adjusted D-Dimer Policy <a href="https://www.acep.org/patient-care/clinical-policies/acute-venous-thromboembolic-disease/">(ACEP)</a><br>