Introduction



Pulmonary embolism (PE) is caused when a deep venous thrombosis from somewhere else in the body “embolizes” and becomes lodged in the pulmonary arteries



Can cause pulmonary infarction (which mimics pneumonia on chest x-ray)



Basic Approach to the Diagnosis of PE



* 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 Wells’ Criteria for PE by MDCalc)* Define patient as either “Low” “Medium” or “High” risk* PERC criteria* I use the PERC Rule for PE by MDCalc 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 HERE



Final Thoughts



* Bilateral lower extremity ultrasounds not sensitive enough to rule out PE* The classic EKG finding is S1Q3T3



Additional Reading



* Emergency Evaluation of PE: Diagnosis (Journal of Emergency Medicine)* Wells Criteria (MDCalc)* PERC Criteria (MDCalc)* Age Adjusted D-Dimer Policy (ACEP)