Ischemic Stroke
Ischemic stroke can be caused by several different kinds of diseases. The most common problem is narrowing of the arteries in the neck or head. This is most often caused atherosclerosis, or gradual cholesterol deposition. If the arteries become too narrow, blood cells may collect and form blood clots. These blood clots can block the artery where they are formed (thrombosis), or can dislodge and become trapped in arteries closer to the brain (embolism). Another cause of stroke is blood clots in the heart, which can occur as a result of irregular heartbeat (for example, atrial fibrillation), heart attack, or abnormalities of the heart valves. While these are the most common causes of ischemic stroke, there are many other possible causes. Examples include use of street drugs, traumatic injury to the blood vessels of the neck or disorders of blood clotting
A thrombotic stroke occurs when diseased or damaged cerbral arteries become blocked by the formation of a blood clot within the brain. Clinically referred to as cerebral thrombosis or cerebral infarction, this type of event is responsible for almost 50% of all strokes. Cerebral thrombosis can also be divided into an additional two categories that correlate to the location of the blockage within the brain: large-vessel thrombosis and small-vessel thrombosis. Large-vessel thrombosis is the term used when the blockage is in one of the brain's larger blood-supplying arteries such as the carotid or middle cerebral, while small-vessel thrombosis involves one (or more) of the brain's smaller, yet deeper penetrating arteries. This latter type of stroke is also called a lacuner stroke
An embolic stroke is also caused by a clot within an artery, but in this case the clot (or emboli) was formed somewhere other than in the brain itself. Often from the heart, these emboli will travel the bloodstream until they become lodged and can not travel any further. This naturally restricts the flow of blood to the brain and results in almost immediate physical and neurological deficits
Causes
Ischemic stroke is caused by several diseases
- Atherosclerosis (hardening of the arteries), caused by a cholesterol deposition that narrows the blood vessels is the most common cause of ischemic stroke. As arteries narrow, blood cells may collect and form blood clots. These blood clots can block the artery where they are formed (thrombosis), or can dislodge and become trapped in arteries closer to the brain (embolism). Refer to Dr. Ruth McPherson’s information
- Blood clots in the heart can occur as a result of irregular heartbeat, atrial fibrillation, heart attack, patent foramen ovale or abnormalities of the heart valves.
- Use of street drugs (cocaine)
- Blood clotting disorders, like Lupus, Factor V Leiden or Antiphospholipid syndrome
- Carotid or vertebral artery dissection
- Unusual cardiac sources — like infections
- Vasculitis/Arteritis/Phlebitis
While these are the most common causes of ischemic stroke, there are many other possible causes. Especially in younger people, it is important to look for the uncommon causes. There may be multiple causes of the stroke as well. For example in young women - migraine and taking birth control pills or a patent foramen ovale complicated by APS ( a clotting disorder)
Who gets it?
Ischemic stroke accounts for about 80% of all strokes. The risk of ischemic stroke rises as you get older (60 or more years old). At each age, stroke is more common in men than women and it is more common among black people than white people (People that are black are more likely to have uncontrolled high blood pressure). Diabetes, high blood pressure and smoking put you at higher risk of having a stroke. See Risk Factors of Stroke
Treatment
The best emergency treatment for an ischemic stroke without secondary hemorrhage is
- tPA — a clot buster that breaks up the clot, or
- the Merci Retriever — a corkscrew like device that breaks though or retrieves the clot or embolus
Information
For the majority of people arteriosclerosis will be the cause of your ischemic stroke
Embolism causes of stroke: atrial fibrillation, atheroma, atherosclerosis, venous thrombus circulating in blood
Hypercoaguable States or Blood Clotting Disorders: Systemic Lupus Erythematosus, antiphospholipid antibody syndromes, deficiency of antithrombin III or protein S or C, resistance to activated protein C, increased factor VIII)
Unusual Cardiac sources
Homocysteine
Patent Foramen Ovale
Links to Information on Tissue Plasmogen Activator tPA and its use in emergency stroke care treatment
Links to information the the Merci Retriever
Migraine and Stroke (Controlled studies of patients with ischemic stroke report an association with migraine, especially in women aged less than 45 years who have a history of migraine with aura. The risk at age 40 is thought to be 36 per 100,000 women who get migraines)
Other Links
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