In a society of fast food and video games, increasing numbers of children are being diagnosed with childhood obesity, high cholesterol levels, high blood pressure and even atherosclerosis (hardening of the arteries). These risk factors for adult stroke rarely contribute to pediatric stroke. About 25 percent of pediatric strokes are related to heart diseases that are present since birth (congenital heart diseases). They include:

• Aortic stenosis. A narrowing of the aortic valve.
  
  
• Atrial septal defect. A hole in the wall (septum) between the upper chambers of the heart (atria).
  
  
• Mitral stenosis. A narrowing of the mitral valve.
  
  
• Patent ductus arteriosus (PDA). A heart defect that occurs when a blood vessel called the ductus arteriosus fails to close after birth, as it normally should.
  
  
• Tetralogy of Fallot. A condition that involves the “tetralogy” of the following four elements: ventricular septal defect, enlargement of the right ventricle, pulmonic stenosis and a displaced or deviated aorta.
  
  
• Transposition of the great arteries. A type of heart defect in which the two great arteries (the pulmonary artery and the aorta) are in reversed (transposed) locations.
  
  
• Ventricular septal defect. A hole in the wall (septum) between the lower chambers of the heart (ventricles).

Ironically, as the number of infants surviving congenital heart disease has increased, so too has the risk of pediatric stroke.

Beyond congenital heart defects, there are a wide variety of risk factors that may contribute to pediatric stroke. In about half of pediatric stroke cases, more than one of these risk factors is present. Following is a comprehensive list of some of these risk factors as noted by the Ad Hoc Committee on Stroke in Children of the Child Neurology Society.

• Vasospastic disorders:
  
  
• Agenesis/hypoplasia of internal vertebral or carotid arteries. The arteries carrying oxygen-rich blood to the brain are underdeveloped.
  
  
• Arterial fibromuscular dysplasia. The muscle tissue within the arteries is abnormally developed.
  
  
• Arteriovenous malformation. Whereas arteries normally carry blood to the capillaries and then the veins, an arteriovenous malformation is a tangled mass of blood vessels in which the high-pressure, thick-walled arteries are directly connected to the low-pressure, thin-walled veins. When present in the brain, they can increase the risk of stroke.
  
  
• Ergot poisoning. This toxic reaction is the result of eating a fungus that develops on particular grains, usually contaminated bread.
  
  
• Hereditary hemorrhagic telangiectasia. This inherited condition involves clusters of enlarged blood vessels close to the skin’s surface. These clusters may appear on the skin of the face, hands, body and/or limbs and may look like blotches of blue or purple lines on the skin.
  
  
• Carotid cavernous fistula. An abnormal channel that directly links one of the carotid arteries to one of the veins.
  
  
• Cerebral aneurysm. An aneurysm is the dilation, bulging or ballooning out of part of the wall of an artery. When present in the cerebral arteries in the brain, a patient is at risk of the aneurysm bursting (a ruptured aneurysm), leading to a stroke.
  
  
• Migraine. Children with migraine headaches may be at increased risk of stroke.
  
  
• Sturge-Weber syndrome. A condition present since birth, in which the veins are not draining oxygen-poor blood from the face, brain and neck properly. Over time, one or both sides of the brain may be affected.
  
  
• Vasospasm with subarachnoid hemorrhage. A spasm, or squeezing, of a blood vessel in the brain, leading to bleeding between the brain and the skull. This condition puts great pressure on the brain.
  
  
• Systemic vascular diseases (disorders that affect the entire body):
  
  
• Anticardiolipin antibodies. These antibodies are present in the blood of patients with lupus, antiphospholipid syndrome or other conditions that could increase the risk of stroke.
  
  
• Antithrombin IR deficiency. Patients with this condition do not have enough anti-clotting proteins in their blood.
  
  
• Congenital coagulation defects. A condition present since birth that involves abnormal blood clotting.
  
  
• Disseminated intravascular coagulation. Overactivity of the body’s natural clotting system can lead to blood clots and internal bleeding.
  
  
• Hypernatremia. An abnormally high level of sodium in the blood.
  
  
• Hypertension (high blood pressure) or hypotension (low blood pressure).
  
  
• Leukemia. Cancer in the bone marrow.
  
  
• Liver dysfunction with coagulation defect. A type of liver disease with abnormal bleeding.
  
  
• Polycythemia. An abnormally high number of red blood cells.
  
  
• Protein C or protein S deficiency. Either of these blood protein disorders can increase the risk of stroke.
  
  
• Sickle cell anemia. A painful, inherited condition in which the red blood cells are shaped more like half-moons or sickles than round discs.
  
  
• Thrombotic thrombocytopenic purpura. A rare life-threatening blood disorder in which the blood cells that play a key role in blood clotting (platelets) are rapidly consumed by excessive clotting.
  
  
• Acquired diseases (diseases that developed sometime after birth):
  
  
• Arrhythmia. An abnormal heart rhythm.
  
  
• Atrial myxoma. A type of tumor in one of the upper chambers of the heart (atria).
  
  
• Bacterial or Libman-Sacks endocarditis. An inflammation in the lining of the heart or heart valves.
  
  
• Cardiomyopathy. A type of heart disease in which the heart muscle is abnormally enlarged, thickened and/or stiffened.
  
  
• Myocarditis. An inflammation of the heart muscle (myocardium).
  
  
• Rheumatic heart disease. Permanent damage to the heart as a result of rheumatic fever – a condition that can develop from improperly treated cases of strep throat.
  
  
• Rheumatoid arthritis. A type of arthritis that affects knees, elbows or other joints on both sides of the body.
  
  
• Systemic lupus erythematosus. A disease in which the body’s immune system attacks the body’s own connective tissue.
  
  
• Chickenpox (varicella). Studies have shown that up to 30 percent of pediatric ischemic strokes are due to varicella, the virus that causes chicken pox.
  
  
• Injuries or other traumas:
  
  
• Air embolism. Blockage of a blood vessel by an air bubble.
  
  
• Amniotic fluid/placental embolism. Leakage of amniotic fluid into the bloodstream, increasing the risk of blood clot formation.
  
  
• Blunt cervical arterial trauma. An injury in the neck (cervical) area can damage the carotid arteries leading to the brain and increase the risk of stroke.
  
  
• Child abuse. An injury to the neck or head can increase the risk of stroke.
  
  
• Coagulation defect with minor trauma. Even a mild head injury can lead to fatal consequences in a child whose blood does not clot properly.
  
  
• Fat embolism. Blockage of a blood vessel by a fat particle. Often occurs after long bone fractures.
  
  
• Penetrating intracranial trauma. A sharp object entering the head can damage the brain and increase the risk of stroke.
  
  
• Trauma from an angiogram. An angiogram is a special x-ray of the heart and/or coronary blood vessels. It uses a catheter to inject a dye into the bloodstream in order to get a clear image of the target area.
  
  
• Trauma from medical procedures that could affect the blood supply to the brain.
  
  
• Vertebral occlusion following abrupt cervical rotation. Blockage of an artery in the neck following a sudden, sharp turning of the head.
  
  
• Various forms of vasculitis (inflammation of the blood vessels), including:
  
  
• Dermatomyositis
• Granulomatous angiitis
• Hemolytic-uremic syndrome
• Inflammatory bowel disease
• Meningitis
• Polyarteritis nodosa
• Takayasu’s arteritis
  
  
• Various types of vasculopathy, including:
  
  
• Ehler’s-Danlos syndrome. An inherited disorder affecting connective tissue.
  
  
• Fabry’s disease. A metabolic deficiency, usually inherited.
  
  
• Homocystinuria. A rare genetic disorder involving high homocysteine levels.
  
  
• Malignant atrophic papulosis. Also known as Degas disease, this involves the blockage of small to medium-sized arteries.
  
  
• Moyamoya syndrome. A disease of unknown cause in which arteries narrow or even close as they enter the brain.
  
  
• Pseudoxanthoma elasticum. A condition that can lead to calcification (“hardening”) of the arteries, increasing the risk of stroke or heart attack.
  
  
• Other risk factors:
  
  
• Artificial heart valve. When a man-made valve is used to replace one of a patient’s own valves, there is a greater risk of blood clots forming around the foreign substance in the body. Patients with artificial heart valves typically take anticoagulants for the rest of their lives to reduce this risk.
  
  
• Diabetes. A disorder in the body’s ability to use blood sugar (glucose), either due to a lack of, or an inability to use, insulin.
  
  
• Illegal drug use. Recreational drugs such as cocaine and amphetamines can increase the risk of stroke, heart attack and other potentially fatal consequences.
  
  
• Teenage oral contraceptive use. Like women of any age, teenagers who take birth control pills may be at higher risk of stroke.
  
  
• Teenage pregnancy/postpartum. A teenage pregnancy can increase the risk of stroke in females.
  
  
• Vitamin K deficiency. A lack of vitamin K may also be a risk factor for pediatric stroke.