Stroke in Children

Stroke symptoms vary widely depending on which part of the child's brain has been injured. Some parts of the brain can suffer stroke with little or no recognizable symptoms, referred to as "silent" strokes. Other strokes, even very small ones, can cause significant disability, such as paralysis, blindness, cognitive compromise, or even death, if they occur in sensitive areas of the brain.

If you see any of these symptoms in your child, go directly to an emergency room immediately:

• Weakness on one side of the body
• Difficulty speaking
• Difficulty walking or instability when standing
• Vision loss
• First-time seizure
• A change in mental state

Short episodes of weakness or numbness on one side of the body, difficulty speaking, or a sensation that the room is spinning may mean your child is having a transient ischemic attack (TIA), a possible warning sign of stroke that requires immediate evaluation in an emergency room.

Brain cells are incredibly delicate and require a steady supply of oxygen and other nutrients such as glucose. Even brief interruptions in the delivery of oxygen can cause injury. Strokes are caused by three main mechanisms:

• The blood supply to the brain may be blocked. This may occur when a tiny clot (called an thromboembolus) plugs a blood vessel in the brain. This can happen in a number of conditions of childhood and thorough evaluation is required, which the team at the Stroke and Cerebrovascular Center can provide. In addition, the vessels themselves may be narrowed, reducing the amount of blood delivered to the brain, as is seen in childhood cerebral arteriopathy. Moyamoya disease is an example of cerebral arteriopathy.
• The blood may not contain enough oxygen. This may occur in cases when a child can't breathe for long periods of time or has carbon monoxide poisoning. Alternatively, if the heart isn't beating appropriately, the blood may not circulate fast enough to bring fresh blood with oxygen to the brain.
• The brain might be under pressure. This can occur when the brain swells after trauma or when there is bleeding around the brain. There may be bleeding within the brain itself, which directly injures the brain tissue and also makes it harder for blood with oxygen to be delivered to it. This increased pressure often prevents oxygenated blood from the heart from entering the confines of the skull.

In all of these cases, the injury to the brain tissue and the lack of oxygen cause some of the brain cells to die, resulting in a stroke. Childhood stroke can be associated with congenital heart disease, abnormalities in blood vessels, disorders that increase the blood's tendency to clot, infection, or inflammation. Strokes occur more often in boys than girls and more often in African Americans than in Caucasians.

Most pediatric strokes are ischemic or thrombotic in nature, meaning that blood has stopped flowing to an area of the brain for long enough to cause damage.

The major pediatric stroke conditions we treat include:

• Neonatal stroke: Also known as stroke in newborns, neonatal stroke occurs in approximately 1 in 2,500 full-term infants and even more commonly in babies born prematurely. Sometimes strokes even occur before birth. Most often, neonatal stroke is discovered shortly after birth in babies who have seizures or who are weak and unresponsive, and confirmed through neuroimaging.
• Ischemic stroke: Arterial ischemic strokes (AIS) in children are usually due to obstruction of blood flow to a region of the brain or spinal cord, which prevents oxygen from being delivered to it. AIS can be caused by blood clots that form inside an artery in the brain or spinal cord or by clots that pass through the heart, enter the general circulation, and then lodge in an artery in the brain or spinal cord. Structural abnormalities of the cerebral arteries themselves, known as cerebral arteriopathies, can also cause AIS. Examples include cerebral vasculitis, Ehlers-Danlos syndrome, and moyamoya disease.
• Hemorrhagic stroke: Rather than ischemia, or obstruction of blood flow, some strokes occur due to bleeding, or hemorrhage, within the brain. This bleeding usually results from blood-vessel abnormalities, such as cavernous malformations, arteriovenous malformations, venous angioma, and aneurysm. Clotting disorders such as hemophilia, sickle cell disease, brain tumors, and congenital heart disease can also cause bleeds that lead to hemorrhagic stroke. Hemorrhagic stroke is also referred to as cerebral hemorrhage or intracranial hemorrhage. Occasionally, children with ischemic stroke can develop hemorrhagic transformation of their initial stroke, meaning that bleeding can sometimes develop as a complication of the ischemic injury itself or the medicine used to treat it.
• Non-traumatic cerebral hemorrhage: This term refers to bleeding in the brain that does not arise from trauma, but from blood vessel abnormalities or other disorders. It can lead to hemorrhagic stroke, but research indicates that about half of children with non-traumatic intracranial hemorrhage will have no lasting deficit. We provide close follow-up of these children to ensure optimum long-term outcomes.
• Cerebral sinus thrombosis: Cerebral sinus thrombosis occurs when a blood clot forms in the brain's veins and dural sinuses, channels that return blood from the brain to the heart. It has been increasingly diagnosed in newborns and children, and can cause both ischemic stroke and hemorrhagic stroke. Previously, clinicians were reluctant to treat this condition with anticoagulants, which themselves can pose some risks, but confidence has grown in using these medications to prevent injury from the blood clot in selected newborns and children. These children are closely monitored by the Thrombosis and Anticoagulation Program at Boston Children's, which collaborates closely with the Stroke and Cerebrovascular Center.
• Cortical venous thrombosis: Cortical (or cerebral) venous thrombosis occurs when a blood clot forms in a vein within the brain. Such clots can obstruct blood flow and increase blood pressure in the brain's venous circulation (the side of the circulation that returns blood to the heart), sometimes to the point that an ischemic stroke occurs. It is important to detect cortical venous thrombosis early and to consider treatment with anticoagulation.
• Transient ischemic attack: Also known as TIAs, these are temporary deficits in neurologic function caused by a brief interruption of blood flow to part of the brain. While symptoms are short-lived and resolve on their own, TIAs can cause lasting injury to brain tissue. Our research indicates that about 10 percent of children who experience a TIA ultimately have a stroke, sometimes with little or no warning.

During the acute period — soon after a stroke has started — our first priority is to diagnose the underlying cause. We carefully image the brain to determine the extent of the stroke and which areas of the brain are affected. Diagnostic procedures we use to diagnose stroke include:

• Imaging of the brain and blood vessels in the head and neck using MRI, CT, and catheter angiography
• A cardiology evaluation to look at the heart for possible cardio-embolic causes of stroke
• blood tests, including a panel of tests associated with bleeding or clotting disorders (thrombophilia testing), inflammatory disorders, or metabolic disorders
• Genetic studies to look for hereditary risk factors for blood clots a transcranial ultrasound assessment to assess blood flow in the brain

These assessments allow clinicians to take steps to prevent stroke from recurring.

The treatment of a stroke has two parts:

Immediate treatment for stroke

When treating an acute stroke, your doctor will quickly assess whether clot-busting (thrombolytic) medicine, such as tissue plasminogen activator (tPA), or thrombectomy is appropriate for your child. Previously used only in adults, this treatment can open up blood vessels obstructed by blood clots and limit the stroke's effect on the brain. Currently tPA must be given within the first 4½ hours after onset of symptoms to be effective.

In some critically ill patients, your doctor may perform endovascular thrombectomy. This treatment involves navigating a very small catheter directly into the area of the clot and removing the clot itself.

When thrombus removal isn't an option, the goal is to provide the best neuroprotective care possible to limit further damage to the brain. This care focuses on maintaining high blood oxygen levels and optimal blood pressure, to ensure the brain receives the blood flow and oxygen it needs, and controlling blood glucose levels and treating fever, which can exacerbate injury to the brain from stroke.

Long-term care for stroke

Regardless of the cause, the problems that result from the stroke (such as weakness and numbness) often improve with therapy over time. After the acute period has passed, children are closely followed by the Boston Children's Hospital Stroke and Cerebrovascular Center outpatient program, under the care of a child neurologist, hematologist, physiatrist, neuropsychologist, and neuroradiologist as well as occupational and physical therapists.

Our team creates a comprehensive rehabilitation plan for each child to address the long-term consequences of the stroke. This can involve physical, occupational, vision or speech and language therapies or a combination of these. Continuing neurosurgical and neuroradiologic care are also available.

Stroke can very suddenly change a child's learning profile and school performance. Each child in the Stroke and Cerebrovascular Center receives neuropsychological evaluations to inform academic planning. These assessments, conducted by an experienced neuropsychologist, provide a profile of cognitive function and lead to specific recommendations for how to best structure the child's educational program.

The diverse team of specialists in the Stroke and Cerebrovascular Center provides fast, comprehensive evaluation to identify quickly if and why a stroke has occurred. We are skilled in administering therapies in the earliest stages of stroke that are designed to remove blockages of blood vessels in the brain.

If the stroke is caused by malformations of the blood vessels in the brain, our team can treat your child using surgical- or catheter-based techniques.

Our team approach means that your child will benefit from the combined expertise of child neurologists, pediatric neurosurgeons, hematologists, pediatric physiatrists, neurointerventional radiologists, pediatric neuroradiologists, emergency medicine physicians, neuropsychologists, physical and occupational therapists, and speech and language therapists. We also offer long-term multidisciplinary care to help prevent additional strokes in the future.