What tests may be done in the emergency department when a stroke is suspected?
When a stroke is suspected, the emergency department performs a neurological exam, CT scan, blood tests, and an electrocardiogram to distinguish bleeding from a blockage.
By Dr. Martin Roberto Casas MartínezOct 5, 20266 min read
In this article
- Why is time part of the assessment?
- What does the care team check before any tests?
- Which brain scans are done first, and why?
- What blood tests and other tests are ordered?
- How do doctors tell bleeding from a blockage?
- Frequently asked questions
- What should I ask the treating team in the emergency department?
- References
Summary: When a stroke is suspected in the emergency department, the team performs a rapid neurological assessment, a noncontrast head CT scan, blood tests, and an electrocardiogram, almost at the same time. The main goal is to determine whether an artery is blocked or there is bleeding, because treatment changes completely depending on the situation. If symptoms come on suddenly, call 911: these tests are done at the hospital, not beforehand.
If you notice sudden weakness on one side of the body, difficulty speaking, vision loss, or a very severe, sudden headache, call 911 immediately; don’t stop to read or gather documents. This article explains which tests may be done in the emergency department when a stroke is suspected, so the person accompanying the patient can understand what is happening at the hospital.
Why is time part of the assessment?
Because during a stroke (interruption of blood flow to an area of the brain), cells are damaged within minutes, and several treatment options can only be offered within a certain period after symptoms begin; that is why tests are done in parallel.
The IMSS clinical practice guideline on ischemic stroke (2017) sets the goal of performing a CT scan within the first 25 minutes after arrival and interpreting it within the first 45. These time frames explain why everything seems to happen at once in the emergency department.
What does the care team check before any tests?
Before imaging, a doctor performs a quick neurological exam, checking alertness, strength and sensation in the face, arms, and legs, speech and comprehension, and balance. The doctor also asks when the symptoms began and what medical conditions and medications the person has.
The time symptoms began is as valuable as any imaging, because treatment options depend on it. If you were with the person from the beginning, report the time as accurately as possible.
The American Stroke Association notes that the team must also rule out other conditions that can mimic a stroke, such as seizures, fainting, migraine, or heart problems.
Which brain scans are done first, and why?
A noncontrast head computed tomography (CT) scan is usually the first imaging test: it takes just minutes and is primarily used to identify bleeding. IMSS guidelines recommend that no specific therapy be started without prior brain imaging.
A CT scan does not show everything: during the first few hours, a stroke may not yet be visible, and some types of bleeding require additional tests, so an initial “normal” CT scan does not rule out the problem.
Magnetic resonance imaging (MRI), especially the diffusion sequence, detects early areas of ischemia (lack of blood flow) with greater sensitivity, but takes longer. CT angiography or MR angiography shows the arteries in the neck and brain and is used to assess whether a large vessel is blocked and could be treated from inside the artery.
What blood tests and other tests are ordered?
While imaging is being done, blood samples are taken to measure glucose, complete blood count (cell count), electrolytes, kidney function, clotting times, and cardiac enzymes, and an electrocardiogram is performed. None of these should delay treatment when it is already indicated.
These tests help rule out causes that mimic a stroke, such as significantly low blood sugar, and determine whether the person can safely receive certain treatments; according to IMSS guidelines, only glucose needs to be known before starting some of them.
An electrocardiogram (a recording of the heart’s electrical activity) looks for abnormal heart rhythms that can cause clots to travel to the brain; it is quick and painless.
How do doctors tell bleeding from a blockage?
By combining the examination with the CT scan and, if needed, other imaging. A stroke can be ischemic—a clot blocks an artery and causes the stroke—or hemorrhagic—a blood vessel ruptures and bleeds—and treatment for one can be harmful in the other.
With the information gathered, the team answers specific questions: what type of stroke it is, how long ago it occurred, which artery is affected, and whether there are conditions that limit treatment; only then do they consider therapies to dissolve or remove a clot.
MedlinePlus notes that immediate treatment can save a life and improve the chances of recovery; that is why results are considered as they become available, without waiting for all of them.
Frequently asked questions
Can I ask for an MRI instead of a CT scan?
You can ask, but the choice depends on the treating team. A CT scan is faster and is usually the first test; an MRI detects early ischemia more effectively, but takes longer and may not be immediately available in the emergency department.
What should I do if I don’t know what time the symptoms began?
Tell the team the last time you saw the person without symptoms, such as before they went to bed or during a phone call. If it is not known when the symptoms began, this information helps the team estimate how much time has passed and decide which treatments may be considered.
Why do they repeat tests if the first CT scan was normal?
Because during the first few hours, the stroke may not yet be visible on a CT scan. If symptoms persist, the team may repeat the scan or request an MRI to confirm the diagnosis and adjust treatment; it does not mean anything was done wrong.
What should I ask the treating team in the emergency department?
If symptoms come on suddenly, call 911 first. If your family member is already being evaluated, you don’t need to wait until everything is resolved to ask:
- •Which tests have been done, which are still pending, and what have the images shown so far?
- •Is there anything about my family member’s medical history or medications that would be helpful to share now?
- •What is the next step, and when do you expect to have information to decide on treatment?
Informational notice: This content is for informational purposes and does not replace a medical consultation or constitute a diagnosis.
References
- •
- •
- •
