DDx: Pulmonary Embolism Flashcards Preview

10 PULMONARY AND CRITICAL CARE MEDICINE > DDx: Pulmonary Embolism > Flashcards

Flashcards in DDx: Pulmonary Embolism Deck (10):

Differential Diagnosis of Pulmonary Embolism:

Pulmonary Embolism

Acute coronary syndrome (see Acute Coronary Syndrome)

Pericarditis (see Approach to Chest Pain)

Aortic dissection (see Vascular Disease)

Acute pulmonary edema (see Heart Failure)



Asthma or chronic obstructive pulmonary disease exacerbation

Panic attack


Pulmonary Embolism (PE)

Sudden-onset dyspnea, nonproductive cough, tachycardia, and mild hypoxia is highly suggestive of acute pulmonary embolism (PE). 

Modified Wells score 

 +3 points

Clinical signs of DVT

Alternate diagnosis less likely than PE

 +1.5 points

Previous PE or DVT

Heart rate >100

Recent surgery or immobilization

+1 point



Total score for clinical probability
≤4 = PE unlikely
>4 = PE likely


Given clinical stablity (normotensive, mild hypoxemia) with no evidence of distress, the diagnosis of PE can be confirmed with CT angiography (CTA).  If CTA confirms PE, clinical judgment can dictate whether anticoagulation is initiated or other options are pursued (eg, inferior vena cava filter placement) based on the estimated risk of bleeding from the peptic ulcer.

In low-probability patients, a normal D-dimer can exclude the diagnosis. If intermediate or high probability, ventilation-perfusion scan or spiral CT is indicated.

Ventilation-perfusion scans detect abnormalities of blood flow in comparison to the pattern of ventilation, with areas of mismatch between perfusion and ventilation being evidence of vascular occlusion due to a pulmonary embolus. A ventilation-perfusion scan is the most appropriate study to confirm the suspected diagnosis of pulmonary embolism in a patient with kidney failure

Tx: Early, effective anticoagulation decreases the mortality risk of acute PE and should be considered in patients without absolute contraindications (eg, hemorrhagic stroke, massive gastrointestinal bleed).

In the absence of contraindications, the patient should be treated initially with intravenous or subcutaneous unfractionated heparin, low-molecular-weight heparin, or fondaparinux. Most patients with pulmonary embolism are treated in the hospital, although carefully selected, stable patients may be candidates for outpatient treatment. Following initial therapy, patients are usually transitioned to warfarin for long-term therapy, with factor Xa and direct thrombin inhibitors being increasingly-available options for this purpose.


Acute coronary syndrome (see Acute Coronary Syndrome)

Chest pain associated with specific dynamic ECG and echocardiographic changes. Elevated cardiac enzymes can be seen in both acute coronary syndrome and large pulmonary emboli.


Pericarditis (see Approach to Chest Pain)

Substernal pain that is sharp, dull, or pressure-like, often relieved with sitting forward; usually pleuritic. ECG usually shows ST-segment elevation (usually diffuse), PR-segment depression, and sinus tachycardia.


Aortic dissection (see Vascular Disease)

Substernal chest pain with radiation to the back or mid-scapular region. Chest radiograph may show a widened mediastinal silhouette, a pleural effusion, or both.


Acute pulmonary edema (see Heart Failure)

Elevated venous pressure, S3, bilateral crackles, and characteristic chest radiograph.



Sharp, localized chest pain and fever. Pleural effusion may be present. Diagnosis of exclusion.



Sudden onset of chest pain and dyspnea. Chest radiograph establishes the diagnosis.


Asthma or chronic obstructive pulmonary disease exacerbation

Dyspnea and wheezing; positive response to bronchodilator (asthma). History of these disorders with a compatible course of illness is helpful.


Panic attack

Diagnosis of exclusion. Patient may have a history of somatization.