How to rule out ischemic stroke in a patient experiencing syncope (fainting spells)?

From the Guidelines

To rule out ischemic stroke in a patient with faint spells, a comprehensive evaluation including immediate brain imaging, vascular imaging, and cardiac assessment is essential, as recommended by the Canadian Stroke Best Practice Recommendations, sixth edition practice guidelines, update 2017 1. The evaluation should start with a thorough history and physical examination, focusing on the characteristics of the faint spells, associated symptoms, and risk factors for stroke. Vital signs, including orthostatic measurements, and a complete neurological examination are essential. Brain imaging is crucial - an immediate non-contrast CT scan can rule out hemorrhage, while MRI with diffusion-weighted imaging is more sensitive for detecting acute ischemic changes, as suggested by the Canadian Stroke Best Practice Recommendations 1. Vascular imaging such as carotid ultrasound, CT angiography, or MR angiography should be performed to evaluate for carotid stenosis or other vascular abnormalities, with CT angiography being the ideal method to assess both extracranial and intracranial circulation 1. Cardiac evaluation including 12-lead ECG, echocardiogram, and extended cardiac monitoring (24-hour to 30-day depending on frequency of symptoms) is important to detect arrhythmias like atrial fibrillation, as recommended by the National Institute for Health and Clinical Excellence guideline for management of transient loss of consciousness 1. Laboratory tests should include complete blood count, electrolytes, glucose, renal function, and coagulation studies, as outlined in the Canadian Stroke Best Practice Recommendations 1. For recurrent unexplained episodes, consider tilt-table testing to evaluate for vasovagal syncope or orthostatic hypotension, but only if the initial assessment does not indicate an uncomplicated faint, as suggested by the National Institute for Health and Clinical Excellence guideline 1. The distinction between syncope and TIA/stroke is critical - syncope typically involves loss of consciousness with quick recovery, while focal neurological deficits suggest TIA or stroke. This comprehensive approach helps differentiate between cardiac syncope, orthostatic hypotension, vasovagal syncope, and cerebrovascular events. Key points to consider in the evaluation include:

• A thorough history and physical examination
• Brain imaging with CT or MRI
• Vascular imaging with carotid ultrasound, CT angiography, or MR angiography
• Cardiac evaluation with 12-lead ECG, echocardiogram, and extended cardiac monitoring
• Laboratory tests including complete blood count, electrolytes, glucose, renal function, and coagulation studies
• Consideration of tilt-table testing for recurrent unexplained episodes.

From the Research

Ruling Out Ischemic Stroke in Patients with Faint Spells

To rule out ischemic stroke in patients who have faint spells, several steps can be taken:

• Initial Evaluation: Patients reporting symptoms of transient ischemic attack (TIA) should be sent to an emergency department for immediate evaluation 2.
• Expedited History and Physical Examination: An expedited history and physical examination should be performed to determine if the patient is a candidate for thrombolytic therapy 2.
• Laboratory Tests: Initial testing should include complete blood count with platelet count, prothrombin time, International Normalized Ratio, partial thromboplastin time, and electrolyte and glucose levels 2.
• Imaging Studies: Computed tomographic (CT) scanning of the head should be performed immediately to ensure that there is no evidence of brain hemorrhage or mass 2.
• Physical Examination: A thorough physical examination can help identify signs of ischemic stroke and determine its etiology 3.
• Risk Assessment: The ABCD2 score can be used to predict the risk of stroke after a TIA 4, 5.
• Urgent Evaluation and Management: Urgent evaluation and management can reduce the rate of stroke after TIA by up to 80% 5.
• Imaging of Carotid Arteries, Aorta, and Heart: A comprehensive CT angiography (CTA) protocol can be used to image the brain, carotid arteries, aorta, and heart to investigate potential sources of emboli 6.

Key Findings in Physical Examination

The physical examination can help identify key findings that may indicate the etiology of ischemic stroke, including:

• Vital Signs: Abnormal vital signs, such as blood pressure and heart rate, can indicate the presence of ischemic stroke 3.
• Appearance of the Patient: The patient's appearance, including signs of neurological deficits, can help determine the severity of the stroke 3.
• Auscultation: Auscultation of the carotid arteries and heart can help identify signs of stenosis or other abnormalities 3.
• Eye Examination: An eye examination can help identify signs of ischemic optic neuropathy or other ocular abnormalities 3.