Childhood Stroke: Arterial Ischemic Stroke (AIS)

What is a stroke?

Arteries and veins are called blood vessels. They carry blood, oxygen, and nutrients to all the tissues in the body, including the brain. Blood is pushed through the blood vessels by your heartbeat.

A stroke is a sudden blockage or damage in the blood vessels in part of the brain. This stops blood from flowing to that part of the brain, and as a result, less oxygen and other nutrients can get to that part of the brain. This can cause some permanent damage and stop it from working properly.

This page explains some of the possible causes of stroke in children, what test may be used when a stroke is suspected, and available treatment options. The warning signs of stroke are also discussed.

A stroke can happen to anyone at any age. Strokes happen in babies, children, and teenagers as well as in adults and seniors. There are many reasons why a child might have a stroke that may be different from why adults have stroke.

Finding the cause of the stroke is important, for these reasons:

  • It helps decide what kind of treatment is best.
  • It may help prevent more damage.
  • It may stop your child from having another stroke in the future.

Even after many tests, sometimes it is not possible to find out the exact cause of a stroke.

Arterial Ischemic Stroke (AIS)
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A blood clot blocks the flow in a blood vessel in the brain. This can cause damage to brain tissue.
A blood clot is the most common cause of stroke in children

A blood clot is the most common cause of strokes in children. A blood clot or clotting occurs when blood changes from liquid to solid form. Some blood clotting in the body is normal. But a blood clot that gets stuck in a blood vessel while moving through the body is not normal. If this happens in the brain, it can cause a stroke.

A stroke caused by a blood clot is called an ischemic (say: iss-KEE-mik) stroke.

Blood vessels

Arteries and veins are both blood vessels in the body.

  • An artery carries blood from the heart to the body’s tissues, including the brain.
  • A vein carries blood from the body’s tissues back to the heart.

Because there are two kinds of blood vessels, there are 2 kinds of ischemic strokes:

  • A stroke caused by a blood clot in an artery is called arterial ischemic stroke (AIS).
  • A stroke caused by a blood clot in a vein is called cerebral sinovenous thrombosis (CSVT).

Arterial ischemic stroke (AIS)

AIS can occur in either of the following ways:

  • A blood clot forms in the body and travels to a blood vessel in the brain and gets stuck there. This is called an embolism.
  • A blood clot forms directly in an artery that supplies blood to the brain. It blocks blood flow in that artery. This is called thrombosis.

Either way, a blood clot blocks the supply of blood to part of the brain.

Detailed information on strokes caused by cerebral sinovenous thrombosis (CSVT) described breifly above, is available in another brochure.

Warning signs of AIS

Warning signs of AIS in children, teenagers, and young adults

Children, teenagers, and young adults who are having a stroke may suddenly show 1 or more of these signs:

  • find that their face, arm, or leg feels weak or numb, usually on 1 side of the body
  • slur their speech, lose their ability to speak, or have trouble speaking and/or understanding simple statements
  • not see clearly in 1 or both eyes
  • have a new, severe headache with or without vomiting (throwing up)
  • feel very dizzy like the room is 'spinning', lose their balance, have trouble walking, or fall for no reason

Any of these can last for a short time, or they may have lasting effects.

Warning signs of AIS in babies

Babies may show only subtle signs of stroke, such as the following:

  • have seizures without a clear reason
  • have extreme trouble staying awake and alert during the day and outside of their normal sleeping time
  • prefer to use only 1 side of their body as they grow during their first year of life

Possible causes of AIS

About 4 out of 10 strokes occur in children who are otherwise healthy. Some children may have problems with their blood clotting systems.

Other children may already have a serious condition that may lead to a stroke. These conditions include:

  • heart disease which the child was born with (congenital) or acquires later, such as rheumatic heart disease
  • heart or brain surgery
  • sickle cell anaemia
  • leukaemia
  • Moya Moya disease
  • a problem with the system in the body's cells that turns food into energy; this is called metabolic illness
  • blood clotting disorders
  • serious infections, especially in the head and neck
  • migraine headaches
  • accidents involving the head and neck region
  • other trauma

Treating AIS

These are the main goals in the treatment of AIS:

  • Decrease the damage that the stroke can cause.
  • Prevent another stroke from happening.

Treatments may include medicines called blood thinners, which help stop the blood from forming clots. Your child may receive 1 or more of the following blood thinners:

  • warfarin (Coumadin), given by mouth
  • heparin, given intravenously
  • low molecular weight heparin (LMWH), given by injections under the skin
  • acetylsalicylic acid (Aspirin or ASA), given by mouth
  • clopidogrel​ (Plavix), given by mouth

Therapy for stroke

After a stroke, some children may have difficulties physically or mentally. Rehabilitation therapy is very important to help these children recover. Many different health care professionals may help your child, such as:

  • physiotherapists
  • occupational therapists
  • speech language pathologists
  • social workers
  • neuropsychologists

AIS can happen again

There is a chance that a stroke will happen again. This may depend on:

  • what caused the stroke
  • treatment options
  • how well the treatment works
  • your child’s age. For example, newborns who have a stroke are much less likely to have another.

Common tests for childhood stroke

The doctor may order some or all of the following tests when a child has AIS.

Some of these are routine tests, which mean that they are done on many children throughout the hospital for many different reasons. If you want to learn more about an individual test your child is having, ask your health team for more detailed information.

Over time, most of these tests will be repeated to see how well your child is doing.


Blood tests help doctors better understand why your child had a stroke. Children who need to take blood thinners may also need some blood test to see:

  • how well they are working
  • if dosages need to be changed

Arterial Ischemic Stroke Angiogram
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The angiogram shows an artery with an area of irregular narrowing. This can lead to poor blood flow and the formation of clots.
Cerebral angiogram

A cerebral angiogram is a detailed picture of the brain arteries. Your child will have an X-ray while a special dye is injected into the arteries. The dye makes the arteries show up on the X-ray.

Computed tomography (CT) scan

A CT scan uses X-rays to take detailed pictures of the affected area in the brain. This test may show these things:

  • whether or not your child has had a stroke
  • what kind of stroke it is
  • which tissues it has affected

Magnetic resonance imaging (MRI)

An MRI is another way to take detailed pictures of your child’s brain without X-rays. It can show stroke information similar to a CT scan but often in more detail. MRI may show:

  • if your child had a stroke
  • when the stroke happened
  • how serious it is
Arterial Ischemic Stroke MRI
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The light area in this MRI shows damaged brain tissue caused by decreased blood flow from a stroke.

A magnetic resonance angiogram (MRA) works the same way but looks at the arteries in the brain instead of brain tissue.


An echocardiogram uses sound waves to take a picture of your child’s heart.

Lumbar puncture

A lumbar puncture is also called a spinal tap. This test looks for signs of infection or inflammation in your child’s nervous system.

For more information

If you have any questions, please write them down so that your doctor or nurse can answer them for you:


Key points

  • Stroke can occur in people of all ages, including babies and children.
  • Stroke can happen for many different reasons.
  • Trying to find out the cause of stroke is important. It may help decide on the best treatment.
  • Treatment of stroke may include blood thinners. It focuses on minimizing damage and preventing more strokes.

For more information about different types of stroke in children and babies, see "Stroke in Newborns" and "Childhood Stroke: Cerebral Sinovenous Thrombosis (CSVT)."

Gabrielle deVeber, MD, FRCPC

Ivanna Yau, RN, MN, ACNP