Paradoxical Embolism Differential Diagnoses

Updated: Aug 11, 2020
  • Author: Igor A Laskowski, MD; Chief Editor: Vincent Lopez Rowe, MD  more...
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Diagnostic Considerations

Paradoxical embolism (PDE) is a diagnosis of exclusion. It is easily mimicked by other diseases causing cerebral and peripheral arterial embolism. The major difference is that thrombus forms on the left side of the heart, including the atrial or ventricular wall and the mitral or aortic valve. The arterial embolism may lead to permanent damage, resulting in stroke, infarction of organs, or gangrene of extremities (commonly the lower extremities).

Cardioembolism causes approximately 15% of all strokes.

PDE plays a causative role in the etiology of cerebral embolism; other causes include atrial fibrillation, ischemic cardiomyopathy, myocardial infarction (MI), mitral stenosis with or without atrial fibrillation, prosthetic valves, septic endocarditis, atrial myxoma, fat emboli, septal aneurysm, and ascending aortic atherosclerosis.

Peripheral arterial embolism from PDE must be differentiated from embolism of unknown origin. PDE may be associated with a hypercoagulable state, carcinoma (eg, of the pancreas), factor C or S deficiency, factor V Leiden (resistance to activated protein C), and prothrombin mutations. Atherothrombotic arterial manifestations may be difficult to differentiate in the process of trying to rule out the source of the embolus.

The arterial embolism may fragment or lyse, and the circulation may be restored over a period of time or immediately, mimicking a transient ischemic attack (TIA) from a different source. TIA may be a warning sign of eventual permanent neurologic damage.

Current diagnosis of PDE requires the following criteria:

  • Deep vein thrombosis (DVT), with or without pulmonary embolism (PE)
  • Abnormal communication between the right (venous) and left (systemic) sides of the circulatory system
  • Clinical, angiographic, or pathologic evidence of systemic embolism
  • Presence of a favorable pressure gradient promoting right-to-left shunting

When a patent foramen ovale (PFO) is detected in a patient with embolism, leg DVT is present in approximately 90%. DVT may be occult upon physical examination.

Because PDE is a diagnostic challenge that is prone to misdiagnosis, medicolegal action by the patient and family may result. To avoid unwanted medicolegal implications, the index of suspicion for PDE should be high.

Differential Diagnoses

  • Deep Venous Thrombosis