Master the board step 3

Pulmonology
Pulmonary Embolism (PE)
PE presents with the sudden onset of shortness of breath and clear lungs in
patients with risk factors for deep venous thrombosis (DVT). The following are
risk factors for DVT:
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Immobility
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Malignancy
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Trauma
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Surgery, especially joint replacement
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Thrombophilia, such a factor V mutation, lupus anticoagulant, or protein C
and S deficiency
There are no specific physical findings for PE.
Diagnostic Testing
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Chest x-ray: The most common result is normal. The most common abnormality
found is atelectasis. Wedge-shaped infarction and pleural-based
humps are rare.
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EKG: The most common showing is sinus tachycardia. The most common
abnormality is nonspecific ST-T wave changes. Right axis deviation and
right bundle branch block are uncommon.
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ABG: This shows hypoxia with an increased A-a gradient and mild respiratory
alkalosis.
Basic Science Correlate
Mechanism of Right Heart Strain
PE blocks blood flow. Blood flow block causes a severe pressure increase
in the pulmonary artery and right ventricle. The increase in pressure from
increased pressure in PE, not as much the hypoxia-induced vasoconstriction
of COPD. Right heart strain occurs only with the most severe, large emboli
that kill.
Right heart strain + Hypotension = Thrombolytics
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