Transient ischemic attack

Last updated
Transient ischemic attack
Other namesMini-stroke, mild stroke
Specialty Neurology, Vascular surgery
Prognosis Survival rate 91% (to hospital discharge)
67.2% (five years) [1]

A transient ischemic attack (TIA), commonly known as a mini-stroke, is a temporary (transient) stroke with noticeable symptoms that end within 24 hours. A TIA causes the same symptoms associated with a stroke, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language or slurred speech.

Contents

All forms of stroke, including a TIA, result from a disruption in blood flow to the central nervous system. A TIA is caused by a temporary disruption in blood flow to the brain, or cerebral blood flow (CBF). The primary difference between a major stroke and the TIA's minor stroke is how much tissue death (infarction) can be detected afterwards through medical imaging. While a TIA must by definition be associated with symptoms, strokes can also be asymptomatic or silent. In a silent stroke, also known as a silent cerebral infarct (SCI), there is permanent infarction detectable on imaging, but there are no immediately observable symptoms. The same person can have major strokes, minor strokes, and silent strokes, in any order. [2]

The occurrence of a TIA is a risk factor for having a major stroke, and many people with TIA have a major stroke within 48 hours of the TIA. [3] [4] All forms of stroke are associated with increased risk of death or disability. Recognition that a TIA has occurred is an opportunity to start treatment, including medications and lifestyle changes, to prevent future strokes.

Signs and symptoms

Signs and symptoms of TIA are widely variable and can mimic other neurologic conditions, making the clinical context and physical exam crucial in ruling in or out the diagnosis. The most common presenting symptoms of TIA are focal neurologic deficits, which can include, but are not limited to: [5]

Numbness or weakness generally occur on the opposite side of the body from the affected hemisphere of the brain.

A detailed neurologic exam, including a thorough cranial nerve exam, is important to identify these findings and to differentiate them from mimickers of TIA. Symptoms such as unilateral weakness, amaurosis fugax, and double vision have higher odds of representing TIA compared to memory loss, headache, and blurred vision. [7] Below is a table of symptoms at presentation, and what percentage of the time they are seen in TIAs versus conditions that mimic TIA. In general, focal deficits make TIA more likely, but the absence of focal findings do not exclude the diagnosis and further evaluation may be warranted if clinical suspicion for TIA is high (see "Diagnosis" section below). [8]

TIA vis-à-vis mimics

Symptoms [8]  % TIA mimics [8]  % TIAs [8]
Unilateral paresis29.158
Memory loss/cognitive impairment18 to 262 to 12
Headache14.6 to 232 to 36
Blurred vision21.85.2
Dysarthria 12.720.6
Hemianopsia 3.63.6
Transient monocular blindness 06
Diplopia04.8

Non-focal symptoms such as amnesia, confusion, incoordination of limbs, unusual cortical visual symptoms (such as isolated bilateral blindness or bilateral positive visual phenomena), headaches and transient loss of consciousness are usually not associated with TIA, [6] however patient assessment is still needed. Public awareness on the need to seek a medical assessment for these non-focal symptoms is also low, and can result in a delay by patients to seek treatment [9]

Symptoms of TIAs can last on the order of minutes to one–two hours, but occasionally may last for a longer period of time. [10] [3] TIA is defined as ischemic events in the brain that last less than 24 hours. Given the variation in duration of symptoms, this definition holds less significance. [3] A pooled study of 808 patients with TIAs from 10 hospitals showed that 60% lasted less than one hour, 71% lasted less than two hours, and 14% lasted greater than six hours. [11] Importantly, patients with symptoms that last more than one hour are more likely to have permanent neurologic damage, making prompt diagnosis and treatment important to maximize recovery. [3]

Cause

The most common underlying pathology leading to TIA and stroke is a cardiac condition called atrial fibrillation, where poor coordination of heart contraction may lead to a formation of a clot in the atrial chamber that can become dislodged and travel to a cerebral artery. [12] [13] Unlike in stroke, the blood flow can become restored prior to infarction which leads to the resolution of neurologic symptoms. [5] [12] Another common culprit of TIA is an atherosclerotic plaque located in the common carotid artery, typically by the bifurcation between the internal and external carotids, that becomes an embolism to the brain vasculature similar to the clot in the prior example. [12] [13] A portion of the plaque can become dislodged and lead to embolic pathology in the cerebral vessels. [12]

In-situ thrombosis, an obstruction that forms directly in the cerebral vasculature unlike the remote embolism previously mentioned, is another vascular occurrence with possible presentation as TIA. [12] Also, carotid stenosis secondary to atherosclerosis narrowing the diameter of the lumen and thus limiting blood flow is another common cause of TIA. [12] Individuals with carotid stenosis may present with TIA symptoms, thus labeled symptomatic, while others may not experience symptoms and be asymptomatic. [5] [12] [13]

Risk factors

Risk factors associated with TIA are categorized as modifiable or non-modifiable. Non-modifiable risk factors include age greater than 55, sex, family history, genetics, and race/ethnicity. [12] [14] Modifiable risk factors include cigarette smoking, hypertension (elevated blood pressure), diabetes, hyperlipidemia, level of carotid artery stenosis (asymptomatic or symptomatic) and activity level. [12] [13] [14] The modifiable risk factors are commonly targeted in treatment options to attempt to minimize risk of TIA and stroke. [3] [12] [13]

Pathogenesis

There are three major mechanisms of ischemia in the brain: embolism traveling to the brain, in situ thrombotic occlusion in the intracranial vessels supplying the parenchyma of the brain, and stenosis of vessels leading to poor perfusion secondary to flow-limiting diameter. [12] [13] Globally, the vessel most commonly affected is the middle cerebral artery. [12] Embolisms can originate from multiple parts of the body.

Common mechanisms of stroke and TIA: [12]

Stroke mechanismFrequencyPattern of infarctsNumber of infarcts
In situ thrombotic occlusionUncommonLarge subcortical; Sometimes with borderzone; Rarely, whole territory; Sometimes enlargingSingle
Artery to artery embolismCommonSmall cortical and subcorticalMultiple
Impaired clearance of emboliCommonSmall, scattered, alongside the borderzone regionMultiple
Branch occlusive diseaseCommonSmall subcortical, lacune-likeSingle
HemodynamicUncommonBorderzone; may be without lesionMultiple; None

Diagnosis

The initial clinical evaluation of a suspected TIA involves obtaining a history and physical exam (including a neurological exam). [6] History taking includes defining the symptoms and looking for mimicking symptoms as described above. Bystanders can be very helpful in describing the symptoms and giving details about when they started and how long they lasted. The time course (onset, duration, and resolution), precipitating events, and risk factors are particularly important.

The definition, and therefore the diagnosis, has changed over time. TIA was classically based on duration of neurological symptoms. The current widely accepted definition is called "tissue-based" because it is based on imaging, not time. The American Heart Association and the American Stroke Association (AHA/ASA) now define TIA as a brief episode of neurological dysfunction with a vascular cause, with clinical symptoms typically lasting less than one hour, and without evidence of significant infarction on imaging. [3]

Laboratory workup

Laboratory tests should focus on ruling out metabolic conditions that may mimic TIA (e.g. hypoglycemia), in addition to further evaluating a patient's risk factors for ischemic events. All patients should receive a complete blood count with platelet count, blood glucose, basic metabolic panel, prothrombin time/international normalized ratio, and activated partial thromboplastin time as part of their initial workup. [15] These tests help with screening for bleeding or hypercoagulable conditions. Other lab tests, such as a full hypercoagulable state workup or serum drug screening, should be considered based on the clinical situation and factors, such as age of the patient and family history. [8] A fasting lipid panel is also appropriate to thoroughly evaluate the patient's risk for atherosclerotic disease and ischemic events in the future. [8] Other lab tests may be indicated based on the history and presentation; such as obtaining inflammatory markers (erythrocyte sedimentation rate and C-reactive protein) to evaluate for giant cell arteritis (which can mimic a TIA) in those presenting with headaches and monocular blindness. [6]

Cardiac rhythm monitoring

An electrocardiogram is necessary to rule out abnormal heart rhythms, such as atrial fibrillation, that can predispose patients to clot formation and embolic events. [15] Hospitalized patients should be placed on heart rhythm telemetry, which is a continuous form of monitoring that can detect abnormal heart rhythms. [6] Prolonged heart rhythm monitoring (such as with a Holter monitor or implantable heart monitoring) can be considered to rule out arrhythmias like paroxysmal atrial fibrillation that may lead to clot formation and TIAs, however this should be considered if other causes of TIA have not been found. [8] [3]

Imaging

According to guidelines from the American Heart Association and American Stroke Association Stroke Council, patients with TIA should have head imaging "within 24 hours of symptom onset, preferably with magnetic resonance imaging, including diffusion sequences". [3] MRI is a better imaging modality for TIA than computed tomography (CT), as it is better able to pick up both new and old ischemic lesions than CT. CT, however, is more widely available and can be used particularly to rule out intracranial hemorrhage. [8] Diffusion sequences can help further localize the area of ischemia and can serve as prognostic indicators. [15] Presence of ischemic lesions on diffusion weighted imaging has been correlated with a higher risk of stroke after a TIA. [16]

Vessels in the head and neck may also be evaluated to look for atherosclerotic lesions that may benefit from interventions, such as carotid endarterectomy. The vasculature can be evaluated through the following imaging modalities: magnetic resonance angiography (MRA), CT angiography (CTA), and carotid ultrasonography/transcranial doppler ultrasonography. [3] Carotid ultrasonography is often used to screen for carotid artery stenosis, as it is more readily available, is noninvasive, and does not expose the person being evaluated to radiation. However, all of the above imaging methods have variable sensitivities and specificities, making it important to supplement one of the imaging methods with another to help confirm the diagnosis (for example: screen for the disease with ultrasonography, and confirm with CTA). [17] Confirming a diagnosis of carotid artery stenosis is important because the treatment for this condition, carotid endarterectomy, can pose significant risk to the patient, including heart attacks and strokes after the procedure. [17] For this reason, the U.S. Preventive Services Task Force (USPSTF) "recommends against screening for asymptomatic carotid artery stenosis in the general adult population". [17] This recommendation is for asymptomatic patients, so it does not necessarily apply to patients with TIAs as these may in fact be a symptom of underlying carotid artery disease (see "Causes and Pathogenesis" above). Therefore, patients who have had a TIA may opt to have a discussion with their clinician about the risks and benefits of screening for carotid artery stenosis, including the risks of surgical treatment of this condition.

Cardiac imaging can be performed if head and neck imaging do not reveal a vascular cause for the patient's TIA (such as atherosclerosis of the carotid artery or other major vessels of the head and neck). Echocardiography can be performed to identify patent foramen ovale (PFO), valvular stenosis, and atherosclerosis of the aortic arch that could be sources of clots causing TIAs, with transesophageal echocardiography being more sensitive than transthoracic echocardiography in identifying these lesions. [3]

Differential diagnosis

Diagnosis [8] Findings [8]
Brain tumorSevere unilateral headache with nausea and vomiting
Central nervous system infection (e.g., meningitis, encephalitis)Fever, headache, confusion, neck stiffness, nausea, vomiting, photophobia, change in mental status
Falls/traumaHeadache, confusion, bruising
HypoglycemiaConfusion, weakness, diaphoresis
MigrainesSevere headaches with or without photophobia, younger age
Multiple sclerosis Diplopia, limb weakness, paresthesia, urinary retention, optic neuritis
Seizure disorderConfusion with or without loss of consciousness, urinary incontinence, tongue biting, tonic-clonic movements
Subarachnoid hemorrhageSevere headache with sudden onset and photophobia
Vertigo (central or peripheral)Generalized dizziness and diaphoresis with or without hearing loss

Prevention

Although there is a lack of robust studies demonstrating the efficacy of lifestyle changes in preventing TIA, many medical professionals recommend them. [18] These include:

In addition, it is important to control any underlying medical conditions that may increase the risk of stroke or TIA, including: [18]

Treatment

By definition, TIAs are transient, self-resolving, and do not cause permanent impairment. However, they are associated with an increased risk of subsequent ischemic strokes, which can be permanently disabling. [19] Therefore, management centers on the prevention of future ischemic strokes and addressing any modifiable risk factors. The optimal regimen depends on the underlying cause of the TIA.

Lifestyle modification

Lifestyle changes have not been shown to reduce the risk of stroke after TIA. [20] While no studies have looked at the optimal diet for secondary prevention of stroke, some observational studies have shown that a Mediterranean diet can reduce stroke risk in patients without cerebrovascular disease. [21] A Mediterranean diet is rich in fruits, vegetables and whole grains, and limited in red meats and sweets. Vitamin supplementation has not been found to be useful in secondary stroke prevention. [21]

Antiplatelet medications

The antiplatelet medications, aspirin and clopidogrel, are both recommended for secondary prevention of stroke after high-risk TIAs. [22] [21] [23] The clopidogrel can generally be stopped after 10 to 21 days. [23] An exception is TIAs due to blood clots originating from the heart, in which case anticoagulants are generally recommended. [21] After TIA or minor stroke, aspirin therapy has been shown to reduce the short-term risk of recurrent stroke by 60–70%, and the long-term risk of stroke by 13%. [24]

The typical therapy may include aspirin alone, a combination of aspirin plus extended-release dipyridamole, or clopidogrel alone. [21] Clopidogrel and aspirin have similar efficacies and side effect profiles. Clopidogrel is more expensive and has a slightly decreased risk of GI bleed. [21] Another antiplatelet, ticlopidine, is rarely used due to increased side effects. [21]

Anticoagulant medications

Anticoagulants may be started if the TIA is thought to be attributable to atrial fibrillation. Atrial fibrillation is an abnormal heart rhythm that may cause the formation of blood clots that can travel to the brain, resulting in TIAs or ischemic strokes. Atrial fibrillation increases stroke risk by five times, and is thought to cause 10-12% of all ischemic strokes in the US. [21] [25] Anticoagulant therapy can decrease the relative risk of ischemic stroke in those with atrial fibrillation by 67% [26] Warfarin and direct acting oral anticoagulants (DOACs), such as apixaban, have been shown to be equally effective while also conferring a lower risk of bleeding. [25] [27] Generally, anticoagulants and antiplatelets are not used in combination, as they result in increased bleeding risk without a decrease in stroke risk. [21] However, combined antiplatelet and anticoagulant therapy may be warranted if the patient has symptomatic coronary artery disease in addition to atrial fibrillation.

Sometimes, myocardial infarction ("heart attack") may lead to the formation of a blood clot in one of the chambers of the heart. If this is thought to be the cause of the TIA, people may be temporarily treated with warfarin or other anticoagulant to decrease the risk of future stroke. [21]

Blood pressure control

Blood pressure control may be indicated after TIA to reduce the risk of ischemic stroke. About 70% of patients with recent ischemic stroke are found to have hypertension, defined as systolic blood pressure (SBP) > 140 mmHg, or diastolic blood pressure (DBP) > 90 mmHg. [21] Until the first half of the 2010s, blood pressure goals have generally been SBP < 140 mmHg and DBP < 90 mmHg. [21] However, newer studies suggest that a goal of SBP <130 mmHg may confer even greater benefit. [28] [29] Blood pressure control is often achieved using diuretics or a combination of diuretics and angiotensin converter enzyme inhibitors, although the optimal treatment regimen depends on the individual. [21]

Studies that evaluated the application of blood pressure‐lowering drugs in people who had a TIA or stroke, concluded that this type of medication helps to reduce the possibility of a recurrent stroke, of a major vascular event and dementia. [30] The effects achieved in stroke recurrence were mainly obtained through the ingestion of angiotensin-converting enzyme (ACE) inhibitor or a diuretic. [30]

Cholesterol control

There is inconsistent evidence regarding the effect of LDL-cholesterol levels on stroke risk after TIA. Elevated cholesterol may increase ischemic stroke risk while decreasing the risk of hemorrhagic stroke. [31] [32] [33] While its role in stroke prevention is unclear, statin therapy has been shown to reduce all-cause mortality and may be recommended after TIA. [21]

Diabetes control

Diabetes mellitus increases the risk of ischemic stroke by 1.5–3.7 times, and may account for at least 8% of first ischemic strokes. [21] While intensive glucose control can prevent certain complications of diabetes such as kidney damage and retinal damage, there has previously been little evidence that it decreases the risk of stroke or death. [34] However, data from 2017 suggests that metformin, pioglitazone and semaglutide may reduce stroke risk. [34]

Surgery

If the TIA affects an area that is supplied by the carotid arteries, a carotid ultrasound scan may demonstrate stenosis, or narrowing, of the carotid artery. For people with extra-cranial carotid stenosis, if 70-99% of the carotid artery is clogged, carotid endarterectomy can decrease the five-year risk of ischemic stroke by approximately half. [35] For those with extra-cranial stenosis between 50 and 69%, carotid endarterectomy decreases the 5-year risk of ischemic stroke by about 16%. [35] For those with extra-cranial stenosis less than 50%, carotid endarterectomy does not reduce stroke risk and may, in some cases, increase it. [35] The effectiveness of carotid endarterectomy or carotid artery stenting in reducing stroke risk in people with intra-cranial carotid artery stenosis is unknown. [21]

In carotid endarterectomy, a surgeon makes an incision in the neck, opens up the carotid artery, and removes the plaque occluding the blood vessel. The artery may then be repaired by adding a graft from another vessel in the body, or a woven patch. In patients who undergo carotid endarterectomy after a TIA or minor stroke, the 30-day risk of death or stroke is 7%. [35]

Carotid artery stenting is a less invasive alternative to carotid endarterectomy for people with extra-cranial carotid artery stenosis. In this procedure, the surgeon makes a small cut in the groin and threads a small flexible tube, called a catheter, into the patient's carotid artery. A balloon is inflated at the site of stenosis, opening up the clogged artery to allow for increased blood flow to the brain. To keep the vessel open, a small wire mesh coil, called a stent, may be inflated along with the balloon. The stent remains in place, and the balloon is removed.

For people with symptomatic carotid stenosis, carotid endarterectomy is associated with fewer perioperative deaths or strokes than carotid artery stenting. [36] Following the procedure, there is no difference in effectiveness if you compare carotid endarterectomy and carotid stenting procedures, however, endarterectomy is often the procedure of choice as it is a safer procedure and is often effective in the longer term for preventing recurrent stroke. [36] For people with asymptomatic carotid stenosis, the increased risk of stroke or death during the stenting procedure compared to an endarterectomy is less certain. [36]

People who undergo carotid endarterectomy or carotid artery stenting for stroke prevention are medically managed with antiplatelets, statins, and other interventions as well. [21]

Prognosis

Without treatment, the risk of an ischemic stroke in the three months after a TIA is about 20% with the greatest risk occurring within two days of the TIA. [6]  Other sources cite that 10% of TIAs will develop into a stroke within 90 days, half of which will occur in the first two days following the TIA. [37] Treatment and preventative measures after a TIA (for example treating elevated blood pressure) can reduce the subsequent risk of an ischemic stroke by about 80%. [6] The risk of a stroke occurring after a TIA can be predicted using the ABCD² score. One limitation of the ABCD² score is that it does not reliably predict the level of carotid artery stenosis, which is a major cause of stroke in TIA patients. The patient's age is the most reliable risk factor in predicting any level of carotid stenosis in transient ischemic attack. [38] The ABCD2 score is no longer recommended for triage (to decide between outpatient management versus hospital admission) of those with a suspected TIA due to these limitations. [6]

Epidemiology

With the difficulty in diagnosing a TIA due to its nonspecific symptoms of neurologic dysfunction at presentation and a differential including many mimics, the exact incidence of the disease is unclear. It was estimated to have an incidence of approximately 200,000 to 500,000 cases per year in the US in the early 2000s according to the American Heart Association. [3] TIA incidence trends similarly to stroke, such that incidence varies with age, gender, and different race/ethnicity populations. [3] [39] [5] Associated risk factors include age greater than or equal to 60, blood pressure greater than or equal to 140 systolic or 90 diastolic, and comorbid diseases, such as diabetes, hypertension, atherosclerosis, and atrial fibrillation. It is thought that approximately 15 to 30 percent of strokes have a preceding TIA episode associated. [5] [8] [40]

Related Research Articles

<span class="mw-page-title-main">Cerebrovascular disease</span> Condition that affects the arteries that supply the brain

Cerebrovascular disease includes a variety of medical conditions that affect the blood vessels of the brain and the cerebral circulation. Arteries supplying oxygen and nutrients to the brain are often damaged or deformed in these disorders. The most common presentation of cerebrovascular disease is an ischemic stroke or mini-stroke and sometimes a hemorrhagic stroke. Hypertension is the most important contributing risk factor for stroke and cerebrovascular diseases as it can change the structure of blood vessels and result in atherosclerosis. Atherosclerosis narrows blood vessels in the brain, resulting in decreased cerebral perfusion. Other risk factors that contribute to stroke include smoking and diabetes. Narrowed cerebral arteries can lead to ischemic stroke, but continually elevated blood pressure can also cause tearing of vessels, leading to a hemorrhagic stroke.

<span class="mw-page-title-main">Ischemia</span> Restriction in blood supply to tissues

Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism. Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue i.e. hypoxia and microvascular dysfunction. It also implies local hypoxia in a part of a body resulting from constriction.

<span class="mw-page-title-main">Stroke</span> Death of a region of brain cells due to poor blood flow

Stroke is a medical condition in which poor blood flow to a part of 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.

<span class="mw-page-title-main">Amaurosis fugax</span> Medical condition

Amaurosis fugax is a painless temporary loss of vision in one or both eyes.

<span class="mw-page-title-main">Carotid endarterectomy</span> Surgical procedure

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.

<span class="mw-page-title-main">Carotid artery stenosis</span> Narrowing of the carotid arteries

Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis.

<span class="mw-page-title-main">Cerebral infarction</span> Stroke resulting from lack of blood flow

Cerebral infarction, also known as an ischemic stroke, is the pathologic process that results in an area of necrotic tissue in the brain. In mid to high income countries, a stroke is the main reason for disability among people and the 2nd cause of death. It is caused by disrupted blood supply (ischemia) and restricted oxygen supply (hypoxia). This is most commonly due to a thrombotic occlusion, or an embolic occlusion of major vessels which leads to a cerebral infarct. 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.

<span class="mw-page-title-main">Watershed stroke</span> Medical condition

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.

Brain ischemia is a condition in which there is insufficient bloodflow to the brain to meet metabolic demand. This leads to poor oxygen supply or cerebral hypoxia and thus leads to the death of brain tissue or cerebral infarction/ischemic stroke. It is a sub-type of stroke along with subarachnoid hemorrhage and intracerebral hemorrhage.

<span class="mw-page-title-main">Fibromuscular dysplasia</span> Human arterial disease

Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory disease of the blood vessels that causes abnormal growth within the wall of an artery. FMD has been found in nearly every arterial bed in the body, although the most commonly affected are the renal and carotid arteries.

<span class="mw-page-title-main">Hollenhorst plaque</span> Medical condition

A Hollenhorst plaque is a cholesterol embolus that is seen in a blood vessel of the retina. It is usually found when a physician performs ophthalmoscopy, during which a plaque will appear as a small, bright crystal that is refractile and yellow. This is a medical exam finding, and is not a medical condition, though it may be related to cardiovascular conditions such as atherosclerosis of the internal carotid artery. It was first described by American ophthalmologist Robert Hollenhorst in 1961.

<span class="mw-page-title-main">Carotid artery dissection</span> Human disease


Carotid artery dissection is a serious condition in which a tear forms in one of the two main carotid arteries in the neck, allowing blood to enter the artery wall and separate its layers (*dissection*). This separation can lead to the formation of a blood clot, narrowing of the artery, and restricted blood flow to the brain, potentially resulting in stroke. Symptoms vary depending on the extent and location of the dissection and may include a sudden, severe headache, neck or facial pain, vision changes, a drooping eyelid, and stroke-like symptoms such as weakness or numbness on one side of the body, difficulty speaking, or loss of coordination.

<span class="mw-page-title-main">Carotid stenting</span>

Carotid artery stenting is an endovascular procedure where a stent is deployed within the lumen of the carotid artery to treat narrowing of the carotid artery and decrease the risk of stroke. It is used to treat narrowing of the carotid artery in high-risk patients, when carotid endarterectomy is considered too risky.

<span class="mw-page-title-main">Leptomeningeal collateral circulation</span>

The leptomeningeal collateral circulation is a network of small blood vessels in the brain that connects branches of the middle, anterior and posterior cerebral arteries, with variation in its precise anatomy between individuals. During a stroke, leptomeningeal collateral vessels allow limited blood flow when other, larger blood vessels provide inadequate blood supply to a part of the brain.

<span class="mw-page-title-main">C. Miller Fisher</span> Canadian doctor, neurologist, pathologist

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.

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.

John David Spence is a Canadian medical doctor, medical researcher and Professor Emeritus at the University of Western Ontario. He is affiliated with the University of Western Ontario and the Robarts Research Institute, one of Canada's leading medical research organizations. Before his retirement from clinical practice in July 2022, he was also affiliated with the London Health Sciences Centre's University Hospital. He is a recognized expert in stroke prevention and stroke prevention research, with more than 600 peer-reviewed publications since 1970. He delivered more than 600 lectures on stroke prevention in 42 countries. In 2015, he received the Research Excellence Award from the Canadian Society for Atherosclerosis, Thrombosis and Vascular Biology. In 2019, he was appointed a Member of the Order of Canada, and in 2020 he received the William Feinberg Award from the American Heart Association for excellence in clinical stroke research.

A silent stroke is a stroke that does not have any outward symptoms associated with stroke, and the patient is typically unaware they have suffered a stroke. Despite not causing identifiable symptoms, a silent stroke still causes damage to the brain and places the patient at increased risk for both transient ischemic attack and major stroke in the future. In a broad study in 1998, more than 11 million people were estimated to have experienced a stroke in the United States. Approximately 770,000 of these strokes were symptomatic and 11 million were first-ever silent MRI infarcts or hemorrhages. Silent strokes typically cause lesions which are detected via the use of neuroimaging such as MRI. The risk of silent stroke increases with age but may also affect younger adults. Women appear to be at increased risk for silent stroke, with hypertension and current cigarette smoking being amongst the predisposing factors.

Embolic stroke of undetermined source (ESUS) is an embolic stroke, a type of ischemic stroke, with an unknown origin, defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources. As such, it forms a subset of cryptogenic stroke, which is part of the TOAST-classification. The following diagnostic criteria define an ESUS:

References

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