Stroke
Sudden interrupted flow of blood to the brain that can cause symptoms that vary in severity from a temporary weakness to profound paralysis, coma, and death. A stroke occurs when the blood supply to any part of the brain is interrupted, resulting in tissue death and loss of brain function. If blood flow in any of the arteries that lead to the brain is interrupted for longer than a few seconds, brain cells can die, causing permanent damage. There are two types of stroke: hemorrhagic stroke, caused by blood leaking from blood vessels into the brain, or ischemic stroke, caused by a blockage. Although childhood strokes are far less common than adult strokes, they, too, can kill or leave survivors disabled.
Between 1979 and 1998 there were an average of 244 deaths a year due to childhood stroke in the United States. Overall, stroke deaths declined by 58 percent in the 20-year period, but the reduction in deaths varied by type of stroke. Although deaths from stroke in children have declined sharply, black children still have higher stroke death rates than other youngsters.
Recent declines in stroke deaths may be related to better detection methods and to the fact that children now survive previously fatal conditions that can cause strokes, such as prematurity, congenital heart disease, and leukemia.
Perinatal Stroke
Perinatal (or “prenatal”) stroke includes strokes that occur between the 28 weeks of gestation and the 28 days after birth. Stroke occurs more frequently in the perinatal and prenatal age group than in older children.
Some perinatal strokes are caused by inherited clotting disorders or coagulation abnormalities that make the infant more likely to have a blood clot. Congenital heart disease and sickle-cell disease are common causes of stroke in children. No cause can be detected in about a fifth of the children with ischemic stroke, but many of these children seem to recover well after birth.
Cause
Up to one-third of all strokes in children occur for unknown reasons. The most common cause of stroke in children is a heart disorder often related to a developmental defect in the structure of the heart. Disorders of the blood such as SICKLE-CELL DISEASE, blood clotting problems, and genetic disorders, are the next most common causes. Following these, there are a whole variety of causes including infections, abnormal arterial-venous connections in the brain, chicken pox virus, and trauma to the head.
Risk Factors
Childhood stroke deaths are poorly understood, since it is not possible to take the risk factors important for strokes in adults (such as high blood pressure, poor diet, or diabetes) and apply them to children. Experts suspect an unknown genetic predisposition may play a role in these deaths. Hormonal differences may be a factor in the higher stroke rates in boys.
Known risk factors for childhood strokes caused by bleeding include brain tumors or vascular malformations, HEMOPHILIA, cancer, and sickle-cell disease. Childhood strokes caused by blockages (ischemic strokes) have also been linked to sicklecell disease and cancer. Risk factors that contribute to ischemic strokes include MENINGITIS, ENCEPHALITIS, congenital heart disease, and certain blood clotting disorders.
Hemorrhagic strokes showed the steepest drop in death rates in the past 20 years: Childhood stroke deaths from subarachnoid hemorrhagic strokes (bleeding into the space between the brain and the skull) dropped by 79 percent, while strokes from intracerebral hemorrhages (bursting of a defective brain vessel) declined by 54 percent.
The declines were not as dramatic for deaths from ischemic stroke, which results from a blood clot that blocks blood flow to the brain. Ischemic stroke deaths declined 19 percent in the same time period.
Unfortunately, black children and boys have much higher risks for dying of strokes for some unknown reason. Black children were more than twice as likely to die from strokes caused by intracerebral hemorrhage, and about 75 percent more likely to die from ischemic strokes or subarachnoid hemorrhage. No factors (such as sicklecell disease, which is more common in blacks than whites) fully accounted for excess stroke deaths. Boys of all races were also 30 percent more likely to die from subarachnoid hemorrhage and 21 percent more likely to die from intracerebral hemorrhage than girls.
Symptoms
The stroke-related symptoms depend on the area of the brain affected, the extent of the damage, and the cause of the stroke. In infants and very young children, stroke symptoms include seizures, coma, and paralysis of one side of the body; the signs of a stroke may not appear until months, perhaps even years, later so that the child cannot use one hand as agilely as the other or the child may have a slight limp. When stroke occurs in older children, symptoms include a sudden paralysis of one side of the body, difficulty with vision, and/or difficulty with swallowing.
Diagnosis
The sooner a stroke in children is diagnosed and treated, the better the chance they will have to recover. In a child where the brain is still developing, the developing brain may be able to take over for the functions that have been lost as a result of the stroke. A physician can use a variety of tests and scans to learn what type of stroke has occurred, such as a clot or other occlusion in the blood vessel; bleeding into the brain; bleeding around the brain.
Brain scans Magnetic resonance imaging (MRI) or computerized tomography (CT) scans can identify the affected area of the brain and reveal the status of the blood vessels. Younger children may need to be sedated for an MRI.
Blood tests A number of blood tests can be used to check for any chemical problems, infection, or blood clotting that may have caused the stroke. Some of the clotting tests may need to be repeated later on as they may be inaccurate if they are carried out too soon after the stroke.
Echocardiogram This ultrasound scan reveals the structure of the heart to check whether the stroke was caused by a clot moving from the heart to the brain. If traditional scans on the chest do not provide enough information, a more detailed scan can be done using a scanner placed in the child’s throat while under general anesthesia.
Spinal tap In this test, a sample of cerebrospinal fluid is taken from the space around the spine to reveal if there is an infection or chemical imbalance in the body, as a cause or a result of the stroke.
Angiogram This test gives detailed information about the blood vessels in the brain and is usually done only if less invasive scans have not provided answers. For this test a child is given general anesthesia. A fine tube is inserted into a blood vessel at the top of the leg and dye is injected through this into the brain; X-ray pictures are then taken of the blood vessels in the brain.
Treatment
There are several treatments for children who have had a stroke, depending on the different needs of the individual child. Medications include aspirin, heparin, or warfarin, all of which thin the blood and make it less likely to clot. A child given heparin or warfarin needs regular blood tests to monitor the effects. Aspirin is much milder and does not require regular blood monitoring.
Prognosis
The outcome after a stroke is better for children than for adults. Children often have less permanent disability and often only minor delays in the development of coordinated movement or in cognitive functioning. Early diagnosis is important in order to prevent a second stroke and to start treatment to help the child recover fully.
Between 1979 and 1998 there were an average of 244 deaths a year due to childhood stroke in the United States. Overall, stroke deaths declined by 58 percent in the 20-year period, but the reduction in deaths varied by type of stroke. Although deaths from stroke in children have declined sharply, black children still have higher stroke death rates than other youngsters.
Recent declines in stroke deaths may be related to better detection methods and to the fact that children now survive previously fatal conditions that can cause strokes, such as prematurity, congenital heart disease, and leukemia.
Perinatal Stroke
Perinatal (or “prenatal”) stroke includes strokes that occur between the 28 weeks of gestation and the 28 days after birth. Stroke occurs more frequently in the perinatal and prenatal age group than in older children.
Some perinatal strokes are caused by inherited clotting disorders or coagulation abnormalities that make the infant more likely to have a blood clot. Congenital heart disease and sickle-cell disease are common causes of stroke in children. No cause can be detected in about a fifth of the children with ischemic stroke, but many of these children seem to recover well after birth.
Cause
Up to one-third of all strokes in children occur for unknown reasons. The most common cause of stroke in children is a heart disorder often related to a developmental defect in the structure of the heart. Disorders of the blood such as SICKLE-CELL DISEASE, blood clotting problems, and genetic disorders, are the next most common causes. Following these, there are a whole variety of causes including infections, abnormal arterial-venous connections in the brain, chicken pox virus, and trauma to the head.
Risk Factors
Childhood stroke deaths are poorly understood, since it is not possible to take the risk factors important for strokes in adults (such as high blood pressure, poor diet, or diabetes) and apply them to children. Experts suspect an unknown genetic predisposition may play a role in these deaths. Hormonal differences may be a factor in the higher stroke rates in boys.
Known risk factors for childhood strokes caused by bleeding include brain tumors or vascular malformations, HEMOPHILIA, cancer, and sickle-cell disease. Childhood strokes caused by blockages (ischemic strokes) have also been linked to sicklecell disease and cancer. Risk factors that contribute to ischemic strokes include MENINGITIS, ENCEPHALITIS, congenital heart disease, and certain blood clotting disorders.
Hemorrhagic strokes showed the steepest drop in death rates in the past 20 years: Childhood stroke deaths from subarachnoid hemorrhagic strokes (bleeding into the space between the brain and the skull) dropped by 79 percent, while strokes from intracerebral hemorrhages (bursting of a defective brain vessel) declined by 54 percent.
The declines were not as dramatic for deaths from ischemic stroke, which results from a blood clot that blocks blood flow to the brain. Ischemic stroke deaths declined 19 percent in the same time period.
Unfortunately, black children and boys have much higher risks for dying of strokes for some unknown reason. Black children were more than twice as likely to die from strokes caused by intracerebral hemorrhage, and about 75 percent more likely to die from ischemic strokes or subarachnoid hemorrhage. No factors (such as sicklecell disease, which is more common in blacks than whites) fully accounted for excess stroke deaths. Boys of all races were also 30 percent more likely to die from subarachnoid hemorrhage and 21 percent more likely to die from intracerebral hemorrhage than girls.
Symptoms
The stroke-related symptoms depend on the area of the brain affected, the extent of the damage, and the cause of the stroke. In infants and very young children, stroke symptoms include seizures, coma, and paralysis of one side of the body; the signs of a stroke may not appear until months, perhaps even years, later so that the child cannot use one hand as agilely as the other or the child may have a slight limp. When stroke occurs in older children, symptoms include a sudden paralysis of one side of the body, difficulty with vision, and/or difficulty with swallowing.
Diagnosis
The sooner a stroke in children is diagnosed and treated, the better the chance they will have to recover. In a child where the brain is still developing, the developing brain may be able to take over for the functions that have been lost as a result of the stroke. A physician can use a variety of tests and scans to learn what type of stroke has occurred, such as a clot or other occlusion in the blood vessel; bleeding into the brain; bleeding around the brain.
Brain scans Magnetic resonance imaging (MRI) or computerized tomography (CT) scans can identify the affected area of the brain and reveal the status of the blood vessels. Younger children may need to be sedated for an MRI.
Blood tests A number of blood tests can be used to check for any chemical problems, infection, or blood clotting that may have caused the stroke. Some of the clotting tests may need to be repeated later on as they may be inaccurate if they are carried out too soon after the stroke.
Echocardiogram This ultrasound scan reveals the structure of the heart to check whether the stroke was caused by a clot moving from the heart to the brain. If traditional scans on the chest do not provide enough information, a more detailed scan can be done using a scanner placed in the child’s throat while under general anesthesia.
Spinal tap In this test, a sample of cerebrospinal fluid is taken from the space around the spine to reveal if there is an infection or chemical imbalance in the body, as a cause or a result of the stroke.
Angiogram This test gives detailed information about the blood vessels in the brain and is usually done only if less invasive scans have not provided answers. For this test a child is given general anesthesia. A fine tube is inserted into a blood vessel at the top of the leg and dye is injected through this into the brain; X-ray pictures are then taken of the blood vessels in the brain.
Treatment
There are several treatments for children who have had a stroke, depending on the different needs of the individual child. Medications include aspirin, heparin, or warfarin, all of which thin the blood and make it less likely to clot. A child given heparin or warfarin needs regular blood tests to monitor the effects. Aspirin is much milder and does not require regular blood monitoring.
Prognosis
The outcome after a stroke is better for children than for adults. Children often have less permanent disability and often only minor delays in the development of coordinated movement or in cognitive functioning. Early diagnosis is important in order to prevent a second stroke and to start treatment to help the child recover fully.
