Learn EM!

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Let's talk about pulmonary embolism aka PE! It's a can't miss diagnosis in the ED and one you should always consider in patients presenting with syncope. In the U.S alone, PE accounts for approximately 100,000 deaths annually. They are classified into three categories: Massive or high-risk, submassive or intermediate risk, and low risk. Massive meaning evidence of hemodynamic compromise/ hypotension. Submassive meaning without hemodynamic comprimise but with right heart strain. And low-risk which do not encompass any of the features from the above. 

Diagnosis?
It is made with a CT angiogram of the chest which is the gold standard, and a VQ perfusion scan for those who cannot tolerate CT. Two helpful modalities that we use to evaluate further work up for PE are the PERC criteria and Well's score. PERC criteria has a high sensitivity and can be used to eliminate low risk patients without obtaining a d-dimer. The Well's criteria is used to assess high-risk patients, and bypass a D-dimer and proceed with imaging. On board exams ECG findings of "S1Q3T3" should raise a suspicion however in actual practice this is not common nor is a specific ECG findings. The most common ECG and clinical finding of PE is tachycardia, and other supportive findings on ECG including findings of right heart strain such as right axis deviation or inferior lead changes. Another helpful bedside technique that can help tip whether you should perform further diagnostic evaluation for a PE is a helpful bedside ultrasound that can help visualize right sided hypertrophy/ strain!

So how do you treat it? 
Anticoagulation in all categories of PE is the mainstay of treatment. However in patients with evidence of right heart strain or hemodynamic compromise, Alteplase as well as mechanical intervention are also required.

In the case above the patient presented atypically in the sense that he did not have any shortness of breath or evident risk factors for a PE however was borderline tachycardic with a heart rate of 99. Patient also was 55 and was above the age cutoff for the PERC criteria, therefore a D-dimer was added on. The D-dimer came back elevated and a CTA had revealed submassive bilateral pulmonary emboli with evidence of right heart strain and was heparinized and taken to cath lab for intervention. Great case!

Take Home Points:

*Always consider PE in patient's with syncope.

*Use PERC criteria for patients with low suspicion, use Well's criteria with those with high risk factors.

*The most common ECG and clinical finding is Tachycardia.

*Consider bedside ultrasound for right ventricular hypertrophy to aid your clinical suspicion

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