Even Strokes That Disappear in an Hour need Emergency Assessment: Study

In a transient ischemic attack (TIA), the symptoms of stroke disappear in under an hour. While the TIA itself doesn't cause permanent damage, nearly 1 in 5 of those who have a TIA will have a full-blown stroke within three months after the TIA, say researchers

Pic: Pixabay (representational purposes)

According to a new American Heart Association scientific statement published in the Association's journal Stroke, the symptoms of stroke that disappear in under an hour, known as a transient ischemic attack (TIA), need emergency assessment to help prevent a full-blown stroke. The statement offers a standardized approach to evaluating people with suspected TIA, with guidance specifically for hospitals in rural areas that may not have access to advanced imaging or an on-site neurologist. TIA is a temporary blockage of blood flow to the brain.

While the TIA itself doesn't cause permanent damage, nearly 1 in 5 of those who have a TIA will have a full-blown stroke within three months after the TIA, 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 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.

The F.A.S.T. acronym for stroke symptoms can be used to identify a TIA: F - Face drooping or numbness; A - Arm weakness; S - Speech difficulty; T - Time to call the helpline number, even if the symptoms go away. "Confidently diagnosing a TIA is difficult since most patients are back to normal function by the time they arrive at the emergency room," said Hardik P. Amin, M.D., chair of the scientific statement writing committee and associate professor of neurology and medical stroke director at Yale New Haven Hospital, St. Raphael Campus in New Haven, Connecticut. "There also is variability across the country in the workup that TIA patients may receive. This may be due to geographic factors, limited resources at health care centres or varying levels of comfort and experience among medical professionals."

"The statement also includes guidance to help health care professionals tell the difference between a TIA and a "TIA mimic" - a condition that shares some signs with TIA but is due to other medical conditions such as low blood sugar, a seizure or a migraine. Symptoms of a TIA mimic tend to spread to other body parts 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 that increase the risk of a TIA include peripheral artery disease, atrial fibrillation, obstructive sleep apnea and coronary artery disease. In addition, a person who has had a prior stroke is at high risk for 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 an important first assessment. A non-contrast head CT should be done initially in the emergency department to rule out intracerebral haemorrhage and TIA mimics. CT angiography may be done as well to look for signs of narrowing in the arteries leading to the brain. Nearly half of the people with TIA symptoms have narrowing of the large arteries that lead to the brain. A magnetic resonance imaging (MRI) scan is the preferred way to rule out brain injury (i.e., a stroke), ideally done 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 access to an MRI scanner, and they may 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, such as 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, which is 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.

The statement cites research that about 43% of people who had an ischemic stroke (caused by a blood clot) had a TIA within the week before their stroke. Assessing stroke risk after TIAA rapid way to assess a patient`s risk of future stroke after TIA is the 7-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 hospitalization.

Collaboration among emergency room professionals, neurologists and primary care professionals is critical to ensure the patient receives a comprehensive evaluation and a well-communicated outpatient plan for future stroke prevention at discharge."Incorporating these steps for people with suspected TIA may help identify which patients would benefit from hospital admission, versus those who might be safely discharged from the emergency room with close follow-up," Amin said.