PATHOPHYSIOLOGYPrecipitating Factors: Hypertension Predisposing Factors: Hyperlipidemia Life style (sedentary) Diabetes Mellitus VASOCONSTRICTION Vices (Alcohol, smoke) Heart Diseases Age Atherosclerosis Diet Arteriosclerosis Sex Thrombosis Heredity Severe dehydration Blockage of the blood Self-medication vessel Embolism Lack of oxygen & High blood pressure, smoking, heart Ischemic diseases, diabetes, narrowing of nutrients supply arteries supplying the brain, high Stroke cholesterol and an unhealthy lifestyle.Cerebral Ischemia Hypoxia High blood pressure, smoking, and a Subarachnoid family history of burst aneurysms. Hemorrhage- Cell death Altered cerebral- Decreased metabolism Severe dehydration, severe infection Oxygen level in the sinuses of the head and Venous medical or genetic conditions that Stroke increase a person’s tendency to form blood clots. Intracerebral Decreased hemorrhage cerebral perfusion Large Artery Hypertension, diabetes, smoking and Strokes high cholesterol levels. Local P Acidosis A Transient R Ischemic Same with Ischemic stroke Attack A Cytotoxic L Edema Y Small Artery Hypertension, diabetes and S Aneurysm Stroke smoking. I Rupture S Irregular heart beat (atrial fibrillation), Embolic a heart attack (myocardial infarction), strokes heart failure or a small hole in the heart called a PFO (Patent Foramen Ovale). Brain tissue Necrosis DEATH Severe Cases
A stroke is caused by a blocked or bleeding artery in the brain. Moststrokes are due to blocked arteries that supply blood to the brain and are calledischemic strokes. Strokes due to bursting of brain blood vessels are calledhemorrhagic strokes. Intracerebral hemorrhage is caused by bleeding into thebrain itself, while subarachnoid hemorrhage is due to bleeding around the baseof the brain. A TIA (transient ischemic attack) is caused by a temporary blockageof blood flow to a blood vessel to the brain lasting less than 24 hours. Another,rarer, form of stroke can occur when a vein (that drains blood out of the brain) isblocked. This is called a venous stroke.Ischemic Stroke This type of stroke is caused by blockage of a blood vessel (artery)supplying the brain. Brain tissue that no longer receives its blood supply can diewithin a few hours unless something is done to stop the damage. The blockageof arteries can occur in large arteries in the neck or the base of the brain, or insmall arteries inside the brain itself. A blood clot can form in the brain or it canform elsewhere and be carried to the brain by an artery and after having anischemic stroke and the majority of survivors have some long term disability.There are many conditions that increase a persons risk of ischemic stroke.These include high blood pressure, smoking, heart diseases, diabetes, narrowingof arteries supplying the brain, high cholesterol and an unhealthylifestyle. Treating these conditions can decrease stroke risk.Intracerebral Hemorrhage This type of stroke is caused by the bleeding of a blood vessel within thebrain. As a result of the bleeding a blood clot forms in the brain, which putspressure on the brain and damages it. Although intracerebral hemorrhage is lesscommon than ischemic stroke and it is more serious. The most common causeof intracerebral hemorrhage is high blood pressure. Another cause, especially inyounger people with intracerebral hemorrhages, is abnormally formed bloodvessels in the brain (vascular malformations or aneurysms).
Subarachnoid Hemorrhage Subarachnoid hemorrhage results from the bleeding of an artery aroundthe base of the brain. It is the least common stroke type, accounting for about 5%of all strokes. The most frequent cause of subarachnoid hemorrhage is bleedingfrom an aneurysm. An aneurysm is a weakening and ballooning of a short portionof an artery (similar to a bubble on the side of an old hose). The factors that canincrease a person’s risk of this type of stroke include high blood pressure,smoking, and a family history of burst aneurysms.TIA (Transient Ischemic Attack) A TIA is like a temporary ischemic stroke. An artery is temporarily blocked,preventing blood from reaching a part of the brain. This lack of blood flow causesthat part of the brain to stop functioning. The symptoms of a TIA are the same assymptoms of an ischemic stroke. In a TIA, the blood vessel opens up again,before any permanent injury to the brain occurs and the patient recoverscompletely. Most TIA symptoms last less than 30 minutes. People who sufferTIA’s are at HIGH RISK OF STROKE soon thereafter. A TIA should lead toimmediate medical evaluation to determine its cause and a treatment plan toprevent a stroke from following soon after.Venous Stroke Venous stroke is caused by a blood clot blocking the veins that allowblood to drain out of the brain. (All other strokes are caused by abnormalities ofarteries carrying blood to the brain). Venous stroke causes a “back pressure”effect that leads to the stroke. These strokes can be either ischemic orhemorrhagic. Some causes of venous stroke include severe dehydration, severeinfection in the sinuses of the head and medical or genetic conditions thatincrease a person’s tendency to form blood clots.