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      Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    Embolic Stroke of Undetermined Source (ESUS) Criteria

    Diagnoses embolic stroke of undetermined source.


    Use in patients with ischemic stroke only, not hemorrhagic stroke.

    When to Use
    Why Use

    Patients with ischemic stroke of unclear etiology.

    • Diagnosis of ESUS can be established after sufficient evaluation, including long-term cardiac monitoring for ≥24 hours, for occlusive large vessel atherosclerosis and high-risk cardioembolic sources in nonlacunar infarcts.
    • Potential low-risk embolic sources are thought to comprise ESUS.
    • Transesophageal echocardiography (TEE) is not required in ESUS; thus, aortic arch atherosclerosis (shaggy aorta) evaluation is not included. 
    • Studies used to develop ESUS were in predominantly Caucasian populations.
    • An unknown proportion of ESUS patients may have non-embolic stroke mechanisms.
    • Defines cryptogenic stroke based on criteria, rather than from the absence of available test results.
    • Outlines sufficient diagnostic workup in ischemic strokes of unclear etiology not previously described.
    • The prior TOAST stroke classification, a diagnosis of exclusion, classifies a high proportion of strokes as cryptogenic.
    • Enables standardized diagnostic criteria for clinical trials.
    • Used in many ongoing randomized controlled trials studying secondary stroke prevention in patients with cryptogenic strokes.
    All 4 must be present:

    Diagnostic Result:

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    Next Steps
    Creator Insights


    • Strokes that meet ESUS criteria are thought to be due to sources of uncertain risk, including:
      • Minor-risk potential cardioembolic sources.
      • Occult paroxysmal atrial fibrillation.
      • Undiagnosed malignancy.
      • Arteriogenic emboli such as aortic arch atherosclerotic plaques or non-stenotic cerebral arteries.
      • Paradoxical embolism through an atrial septal defect.


    • Depending on clinical suspicion, further evaluation may include any of the following:
      • Prolonged outpatient cardiac monitoring.
      • TEE.
      • Cardiac MRI.
      • Transcranial Doppler with monitoring for emboli.
      • Catheter angioplasty.
      • Workup for occult cancer.
      • Workup for non-embolic causes such as vasculitis.
    • Secondary prevention in all noncardioembolic ischemic strokes includes anti-platelet therapy, blood pressure control, anti-lipid therapy, and lifestyle modifications.
    • The benefit of anticoagulation therapy in ESUS without proven atrial tachyarrhythmia is unclear and the subject of ongoing clinical trials.
    • Certain patients aged ≤60 years with ESUS and patent foramen ovale (PFO) may benefit from percutaneous PFO closure in addition to antiplatelet therapy.
    • In patients with recurrent ESUS, switching antiplatelet agents or starting empiric anticoagulation therapy is reasonable.

    Critical Actions

    All ischemic strokes undergo the same acute therapy management regardless of etiology, including intravenous tPA or mechanical thrombectomy if indicated.

    Content Contributors
    • Dixon Yang, MD
    Reviewed By
    • Cen Zhang, MD
    About the Creator
    Dr. Robert G. Hart
    Are you Dr. Robert G. Hart?
    Content Contributors
    • Dixon Yang, MD
    Reviewed By
    • Cen Zhang, MD