Practice Current: What is your diagnostic evaluation of cryptogenic stroke?

C ryptogenic stroke (CS) accounts for up to one-third of cases of stroke or TIA. CS is defined as brain infarction not attributable to a source of definite cardioembolism, large artery atherosclerosis, or small artery disease despite extensive vascular, cardiac, and serologic evaluation. Patients with CS are heterogeneous by definition and the pathogenic mechanism of CS remains contested. Some authors have stressed the potential role of occult embolism as the prominent etiology for CS and have identified a subset of cases of CS as embolic strokes of undetermined source, defined as a nonlacunar brain infarct without proximal arterial stenosis or cardioembolic sources. This point of view is not shared by others, who believe there is insufficient evidence to support the hypothesis that CS is often caused by occult embolism. Different neurologists utilize distinct strategies for the evaluation of CS, mainly relying on available resources and individual experience. Many times the workup is extensive, often including brain imaging with CT, MRI, or both, vascular imaging with any combination of carotid Doppler ultrasound, CT angiography (CTA), or magnetic resonance angiography (MRA), days or months of cardiac monitoring, transthoracic echocardiogram (TTE) and in some cases transesophageal echocardiogram (TEE), and various blood tests to rule out infection, inflammation, and a hypercoagulable state. Some of these individual tests can cost thousands of dollars and sometimes are performed after discharge from the hospital in the same or different institution, depending on the availability, which may be limited.