Stroke symptoms that disappear in under an hour (known as a transient ischaemic attack – TIA – or warning stroke), need emergency assessment to help prevent a full-blown stroke, says an American Heart Association (AHA) scientific statement published in the Association’s journal Stroke.
The statement offers a standardised approach to evaluating people with suspected TIA, with specific guidance or hospitals in rural areas without access to advanced imaging or an on-site neurologist.
While the TIA itself doesn’t cause permanent damage, nearly one in five of those who have a TIA will subsequently have a full-blown stroke within three months, almost half of which will happen within two days.
For this reason, a TIA is more accurately described as a warning stroke rather than a “mini-stroke”, as it’s often called.
TIA symptoms are the same as stroke symptoms, only temporary. They begin suddenly and may have any or all of these characteristics:
• Symptoms begin strong then fade;
• Symptoms typically last less than an hour;
• Facial droop;
• Weakness on one side of the body;
• Numbness on one side of the body;
• Trouble finding the right words/slurred speech; or
• Dizziness, vision loss or trouble walking.
“Confidently diagnosing a TIA is difficult since most patients are back to normal function by the time they arrive at the emergency room,” said Dr Hardik Amin, chair of the scientific statement writing committee and associate professor of neurology and medical stroke director at Yale New Haven Hospital, Connecticut.
“There is also variability countrywide in the workup that TIA patients receive, possibly be due to geographic factors, limited resources at health care centres or varying levels of comfort and experience among medical professionals.”
For example, Amin said: “Someone with a TIA who goes to an emergency room with limited resources may not get the same evaluation as they would at a certified stroke centre. This statement was written with those emergency room physicians or internists in mind – professionals in resource-limited areas who may not have immediate access to a vascular neurologist and must make challenging evaluation and treatment decisions.”
The statement also includes guidance to help health care professionals tell the difference between a TIA and a “TIA mimic” – a condition with similar signs to TIA but due to other medical conditions like low blood sugar, a seizure or a migraine. Symptoms of a TIA mimic tend to spread to other parts of the body and build in intensity over time.
Who is at risk for a TIA?
People with cardiovascular risk factors, such as high blood pressure, diabetes, obesity, high cholesterol and smoking, are at high risk for stroke and TIA. Other conditions increasing the risk include peripheral artery disease, atrial fibrillation, obstructive sleep apnea and coronary artery disease – also, someone who has previously had a stroke has an increased risk of TIA.
Which tests come first once in the emergency room?
After assessing for symptoms and medical history, imaging of the blood vessels in the head and neck is important. A non-contrast head CT should be done initially in the emergency department to rule out intracerebral haemorrhage and TIA mimics. CT angiography may also be done to detect signs of narrowing in the arteries leading to the brain. Nearly half of people with TIA symptoms have narrowing of the large arteries leading to the brain.
A magnetic resonance imaging (MRI) scan is the preferred way to rule out brain injury (i.e. a stroke), ideally within 24 hours of when symptoms began. About 40% of patients presenting in the ER with TIA symptoms will actually be diagnosed with a stroke based on MRI results. Some emergency rooms may not have an MRI scanner, and might admit the patient to the hospital for MRI or transfer them to a centre with rapid access to one.
Blood work should be completed in the emergency department to rule out other conditions that may cause TIA-like symptoms, like low blood sugar or infection, and to check for cardiovascular risk factors like diabetes and high cholesterol.
Once TIA is diagnosed, a cardiac work-up is advised due to the potential for heart-related factors to cause a TIA. Ideally, this assessment is done in the emergency department, however, it could be coordinated as a follow-up visit with the appropriate specialist, preferably within a week of having a TIA. An electrocardiogram to assess heart rhythm is suggested to screen for atrial fibrillation, detected in up to 7% of people with a stroke or TIA.
The American Heart Association recommends that long-term heart monitoring within six months of a TIA is reasonable if the initial evaluation suggests a heart rhythm-related issue as the cause of a TIA or stroke.
Early neurology consultation, either in-person or via telemedicine, is associated with lower death rates after a TIA. If consultation isn’t possible during the emergency visit, the statement suggests following up with a neurologist ideally within 48 hours but not longer than one week after a TIA, given the high risk of stroke in the days after a TIA. The statement cites research that about 43% of people who had an ischaemic stroke (caused by a blood clot) had a TIA within the week before their stroke.
A rapid way to assess a patient’s risk of future stroke after TIA is the sevev-point ABCD2 score, which stratifies patients into low, medium and high risk based on age, blood pressure, clinical features (symptoms),
Duration of symptoms (less than or greater than 60 minutes) and diabetes. A score of 0-3 indicates low risk, 4-5 is moderate risk and 6-7 is high risk. Patients with moderate to high ABCD2 scores may be considered for hospitalisation.
Statement details
Diagnosis, Workup, Risk Reduction of Transient Ischaemic Attack in the Emergency Department Setting: A Scientific Statement from the American Heart Association (AHA)
Hardik Amin, Tracy Madsen, Dawn Bravata, Charles Wira, Claiborne Johnston, Susan Ashcraft, Tamika Burrus, Peter Panagos, Max Wintermark, Charles Esenwa.
Published in Stroke on 19 January 2023
Abstract
At least 240 000 individuals experience a transient ischaemic attack each year in the United States. Transient ischaemic attack is a strong predictor of subsequent stroke. The 90-day stroke risk after transient ischaemic attack can be as high as 17.8%, with almost half occurring within two days of the index event. Diagnosing transient ischaemic attack can also be challenging, given the transitory nature of symptoms, often reassuring neurological examination at the time of evaluation, and lack of confirmatory testing. Limited resources, such as imaging availability and access to specialists, can further exacerbate this challenge. This scientific statement focuses on the correct clinical diagnosis, risk assessment, and management decisions of patients with suspected transient ischaemic attack. Identification of high-risk patients can be achieved through use of comprehensive protocols incorporating acute phase imaging of both the brain and cerebral vasculature, thoughtful use of risk stratification scales, and ancillary testing with the ultimate goal of determining who can be safely discharged home from the emergency department versus admitted to the hospital. We discuss various methods for rapid yet comprehensive evaluations, keeping resource-limited sites in mind. In addition, we discuss strategies for secondary prevention of future cerebrovascular events using maximal medical therapy and patient education.
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