When a stroke strikes: What to expect at the emergency room

If you suspect that you or someone near you is having a stroke, don’t delay getting help (see “Spot a stroke”). Swift diagnosis and treatment can preserve brain cells and minimize the risk of a devastating disability. You should always call 911 — and not only because traveling via ambulance is faster and safer than driving.

“If the paramedics confirm signs of a possible stroke, they will call ahead to the emergency department so the team who treats stroke patients is prepared and ready,” says Dr. Kori Zachrison, associate professor of emergency medicine at Harvard Medical School. The paramedics will also check the person’s blood sugar, since very high or very low blood sugar levels can mimic the signs of a stroke, she adds.

“Many emergency departments are now set up to bring people with stroke symptoms straight to the CT scanner instead of to a bed in the emergency department,” says Dr. Zachrison. A brain CT scan can immediately rule out or reveal a bleeding (hemorrhagic) stroke (see “Types of strokes”) and guide the choice of treatment.

The 2026 guidelines for early management of stroke from the American Heart Association and American Stroke Association detail recent advances in caring for people with ischemic strokes — those due to a blocked blood vessel and not caused by bleeding. The guidelines include recommendations for expanded access to medications and clot removal procedures. Dr. Zachrison, co-vice chair of the guidelines writing group, explains what stroke patients and their families should know about what happens after they arrive at the hospital.

How family or friends can help

In addition to questions about your medical history, one vital question — “When did your symptoms start?” — helps doctors know if certain treatments are feasible. If you’re not able to answer, they will ask a relative or other trusted person. If needed, hospital staff can call your next of kin or emergency contact.

Doctors often rely on other people to report when the patient was “last known well,” that is, when they were last seen in their normal state of health, without symptoms of a stroke, says Dr. Zachrison. “For example, a daughter might say ‘Dad said that Mom seemed fine when she woke up this morning at seven, but around 9 a.m., he noticed her face looked a little off,’” she says.

Timing matters

According to the new guidelines, anyone with a suspected stroke should receive a brain scan (usually a CT scan) within 25 minutes of arriving at the hospital so doctors can start treatment as soon as possible. Treatment for a hemorrhagic stroke includes medication to control bleeding and reduce pressure in the brain, and sometimes surgery or another procedure to repair damaged blood vessels.

Most ischemic strokes — which are far more common than hemorrhagic strokes — are treated with a clot-dissolving drug, tenecteplase (TNKase) or alteplase (Activase), given through a vein in the arm. The sooner you get one of these clot-busting drugs, the more likely it is to restore blood flow and preserve brain tissue. But getting it too late might not help and also increases the risk of dangerous bleeding, Dr. Zachrison explains. Initially, the window of opportunity for the drug was just three hours. But by the early 2000s, the window was extended to four-and-a-half hours for certain patients.

“Now, we’re increasingly recognizing that everyone’s brain is different in terms of how well their ‘backup’ blood vessels can maintain or restore blood flow to an area damaged by a stroke,” says Dr. Zachrison. Instead of using the clock to decide whether to give medication, doctors can use advanced brain imaging.

So, when someone arrives at the hospital within three hours of when symptoms started and is deemed eligible, they receive the drug right away. But if symptoms began much earlier (or at an unknown time), they’ll likely get another brain scan, says Dr. Zachrison. If the scan shows that brain tissue has not been irreversibly damaged, the clot-busting treatment may still be effective up to nine hours (and sometimes even 24 hours) after stroke symptoms appear, according to the guidelines.

Clot removal procedures

For someone whose stroke results from a clot in a large artery (which is the case in about a quarter of all ischemic strokes), an endovascular thrombectomy (EVT) may be possible. A doctor inserts a catheter into an artery, usually in the groin, and guides it up to the brain to remove the clot using a device called a stent retriever. As with the drug treatment, EVT is now recommended for certain people for up to 24 hours after stroke symptoms appear. But EVT must be done in a specialized stroke center, and few specialists are trained to perform the delicate procedure.

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