Signs and symptoms
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Embolic stroke of undetermined source (ESUS) is an embolic stroke, a type of ischemic stroke, with an unknown origin, [1] defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources. [2] As such, it forms a subset of cryptogenic stroke, which is part of the TOAST-classification. [3] The following diagnostic criteria define an ESUS: [2]
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The following factors are suggested as pathogenesis of ESUS: [4]
ESUS is a diagnosis of exclusion based on radiological and cardiological examinations. For exclusion of haemorrhagic or lacunar strokes CT or MRI imaging is needed. Both procedures also allow detection of embolic pattern of ischemic lesions. 12-lead ECG and cardiac monitoring for at least 24 h with automated rhythm detection are mandated to exclude atrial fibrillation; echocardiography (TTE and/or TEE) is used to detect other major-risk cardioembolic sources (e.g., intracardiac thrombi, or ejection fraction <30%). For imaging of both the extracranial and intracranial arteries supplying the area of brain ischaemia, examination methods like catheter, MR/CT angiography or cervical duplex plus transcranial Doppler ultrasonography are required. They allow an exclusion of large vessel stenosis (≥ 50%). [2]
Cryptogenic stroke is also an ischemic stroke with more than one probable cause or strokes with incomplete diagnostic workup. [3] ESUS has a clearer definition, with an established minimum diagnostic requirements; this is not required in defining a cryptogenic stroke. ESUS is an embolic stroke for which no probable cause can be identified after a standard diagnostic evaluation.[ citation needed ]
Due to the lack of data, there are no specific treatment guidelines for ESUS. Current guidelines recommend antiplatelet therapy for patients with non-cardioembolic ischemic stroke. [8] [9] [10] However, it is widely believed that there is a substantial overlap between ESUS and cardioembolic stroke, clinical trials have assessed the benefit of anticoagulation versus antiplatelet agents for preventing recurrent stroke. [2] [11] Although the existing data does not favor the use anticoagulation in patients with ESUS, current hypotheses suggest there may be subgroups who do benefit from anticoagulation. [12]
On average, ESUS accounts for about 1 in 6 ischemic strokes (17% (range 9 – 25%)) according to a systematic literature review of 9 studies. [13] Patients with ESUS tend to be relatively young and experience mild strokes. However, ESUS is associated with high recurrence rates. Of 2045 ESUS patients (identified by 8 studies)
The stroke recurrence rate was 29.0% over 5 years in patients with ESUS, which is similar to patients with cardioembolic stroke (26.8%), but significantly higher than all types of non-cardioembolic stroke. However, mortality was significantly lower in patients with ESUS than cardioembolic stroke. [14] [15]
A transient ischemic attack (TIA), commonly known as a mini-stroke, is a minor stroke whose noticeable symptoms usually end in less than an hour. TIA causes the same symptoms associated with strokes, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language, slurred speech, or confusion.
Thrombolysis, also called fibrinolytic therapy, is the breakdown (lysis) of blood clots formed in blood vessels, using medication. It is used in ST elevation myocardial infarction, stroke, and in cases of severe venous thromboembolism.
Stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functioning properly.
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA).
Amaurosis fugax is a painless temporary loss of vision in one or both eyes.
Carotid endarterectomy is a surgical procedure used to reduce the risk of stroke from carotid artery stenosis. In endarterectomy, the surgeon opens the artery and removes the plaque. The plaque forms and thickens the inner layer of the artery, or intima, hence the name of the procedure which simply means removal of part of the internal layers of the artery.
Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis.
Desmoteplase is a novel, highly fibrin-specific "clot-busting" (thrombolytic) drug in development that reached phase III clinical trials. The Danish pharmaceutical company, Lundbeck, owns the worldwide rights to Desmoteplase. In 2009, two large trials were started to test it as a safe and effective treatment for patients with acute ischaemic stroke. After disappointing results in DIAS-3, DIAS-4 was terminated, and in December 2014 Lundbeck announced that they would stop the development of desmoteplase.
Cerebral infarction is the pathologic process that results in an area of necrotic tissue in the brain. It is caused by disrupted blood supply (ischemia) and restricted oxygen supply (hypoxia), most commonly due to thromboembolism, and manifests clinically as ischemic stroke. In response to ischemia, the brain degenerates by the process of liquefactive necrosis.
Vertebrobasilar insufficiency (VBI) describes a temporary set of symptoms due to decreased blood flow (ischemia) in the posterior circulation of the brain. The posterior circulation supplies the medulla, pons, midbrain, cerebellum and supplies the posterior cerebellar artery to the thalamus and occipital cortex. As a result, symptoms vary widely depending which brain region is predominantly affected.
A watershed stroke is defined as a brain ischemia that is localized to the vulnerable border zones between the tissues supplied by the anterior, posterior and middle cerebral arteries. The actual blood stream blockage/restriction site can be located far away from the infarcts. Watershed locations are those border-zone regions in the brain supplied by the major cerebral arteries where blood supply is decreased. Watershed strokes are a concern because they comprise approximately 10% of all ischemic stroke cases. The watershed zones themselves are particularly susceptible to infarction from global ischemia as the distal nature of the vasculature predisposes these areas to be most sensitive to profound hypoperfusion.
Vertebral artery dissection (VAD) is a flap-like tear of the inner lining of the vertebral artery, which is located in the neck and supplies blood to the brain. After the tear, blood enters the arterial wall and forms a blood clot, thickening the artery wall and often impeding blood flow. The symptoms of vertebral artery dissection include head and neck pain and intermittent or permanent stroke symptoms such as difficulty speaking, impaired coordination, and visual loss. It is usually diagnosed with a contrast-enhanced CT or MRI scan.
Lacunar stroke or lacunar cerebral infarct (LACI) is the most common type of ischemic stroke, resulting from the occlusion of small penetrating arteries that provide blood to the brain's deep structures. Patients who present with symptoms of a lacunar stroke, but who have not yet had diagnostic imaging performed, may be described as having lacunar stroke syndrome (LACS).
The CHADS2 score and its updated version, the CHA2DS2-VASc score, are clinical prediction rules for estimating the risk of stroke in people with non-rheumatic atrial fibrillation (AF), a common and serious heart arrhythmia associated with thromboembolic stroke. Such a score is used to determine whether or not treatment is required with anticoagulation therapy or antiplatelet therapy, since AF can cause stasis of blood in the upper heart chambers, leading to the formation of a mural thrombus that can dislodge into the blood flow, reach the brain, cut off supply to the brain, and cause a stroke.
Charles Miller Fisher was a Canadian neurologist whose notable contributions include the first detailed descriptions of lacunar strokes, the identification of transient ischemic attacks as stroke precursors, the identification of the link between carotid atherosclerosis and stroke, and the description of a variant form of Guillain–Barré syndrome which bears his name.
Atrial fibrillation is an abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart. It often begins as short periods of abnormal beating, which become longer or continuous over time. It may also start as other forms of arrhythmia such as atrial flutter that then transform into AF.
The ABCD2 score is a clinical prediction rule used to determine the risk for stroke in the days following a transient ischemic attack (TIA, a condition in which temporary brain dysfunction results from oxygen shortage in the brain). Its usefulness was questioned in a 2015 review as it was not found to separate those who are at low from those who are at high risk of future problems. A high score correctly predicted 87% of the people who did have a stroke in the following 7 days but also many people who did not have problems.
The management of atrial fibrillation (AF) is focused on preventing temporary circulatory instability, stroke and other ischemic events. Control of heart rate and rhythm are principally used to achieve the former, while anticoagulation may be employed to decrease the risk of stroke. Within the context of stroke, the discipline may be referred to as stroke prevention in atrial fibrillation (SPAF). In emergencies, when circulatory collapse is imminent due to uncontrolled rapid heart rate, immediate cardioversion may be indicated.
A migrainous infarction is a rare type of ischaemic stroke which occurs in correspondence with migraine aura symptoms. Symptoms include headaches, visual disturbances, strange sensations and dysphasia, all of which gradually worsen causing neurological changes which ultimately increase the risk of an ischaemic stroke. Typically, women under the age of 45 who experience migraine with aura (MA) are at the greatest risk for developing migrainous infarction, especially when combined with smoking and use of oral contraceptives.
The volume of the heart's left atrium is an important biomarker for cardiovascular physiology and clinical cardiology. It is usually calculated as left atrial volume index in terms of body surface area.