There are several types of strokes caused by blocked or ruptured blood vessels in the brain. Ischemic strokes are caused by blocked arteries, cutting off blood flow and oxygen to brain tissue. Hemorrhagic strokes occur when blood vessels rupture, either within the brain itself (intracerebral hemorrhage) or in the space surrounding the brain (subarachnoid hemorrhage). Transient ischemic attacks (TIAs) involve a temporary blockage but no permanent damage. Risk factors for strokes include hypertension, smoking, heart disease, and diabetes.

1. PATHOPHYSIOLOGY
Precipitating 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

2. A stroke is caused by a blocked or bleeding artery in the brain. Most
strokes are due to blocked arteries that supply blood to the brain and are called
ischemic strokes. Strokes due to bursting of brain blood vessels are called
hemorrhagic strokes. Intracerebral hemorrhage is caused by bleeding into the
brain itself, while subarachnoid hemorrhage is due to bleeding around the base
of the brain. A TIA (transient ischemic attack) is caused by a temporary blockage
of 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) is
blocked. 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 die
within a few hours unless something is done to stop the damage. The blockage
of arteries can occur in large arteries in the neck or the base of the brain, or in
small arteries inside the brain itself. A blood clot can form in the brain or it can
form elsewhere and be carried to the brain by an artery and after having an
ischemic stroke and the majority of survivors have some long term disability.
There are many conditions that increase a person's risk of ischemic stroke.
These include high blood pressure, smoking, heart diseases, diabetes, narrowing
of arteries supplying the brain, high cholesterol and an unhealthy
lifestyle. Treating these conditions can decrease stroke risk.
Intracerebral Hemorrhage
This type of stroke is caused by the bleeding of a blood vessel within the
brain. As a result of the bleeding a blood clot forms in the brain, which puts
pressure on the brain and damages it. Although intracerebral hemorrhage is less
common than ischemic stroke and it is more serious. The most common cause
of intracerebral hemorrhage is high blood pressure. Another cause, especially in
younger people with intracerebral hemorrhages, is abnormally formed blood
vessels in the brain (vascular malformations or aneurysms).

3. Subarachnoid Hemorrhage
Subarachnoid hemorrhage results from the bleeding of an artery around
the 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 bleeding
from an aneurysm. An aneurysm is a weakening and ballooning of a short portion
of an artery (similar to a bubble on the side of an old hose). The factors that can
increase 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 causes
that part of the brain to stop functioning. The symptoms of a TIA are the same as
symptoms of an ischemic stroke. In a TIA, the blood vessel opens up again,
before any permanent injury to the brain occurs and the patient recovers
completely. Most TIA symptoms last less than 30 minutes. People who suffer
TIA’s are at HIGH RISK OF STROKE soon thereafter. A TIA should lead to
immediate medical evaluation to determine its cause and a treatment plan to
prevent a stroke from following soon after.
Venous Stroke
Venous stroke is caused by a blood clot blocking the veins that allow
blood to drain out of the brain. (All other strokes are caused by abnormalities of
arteries carrying blood to the brain). Venous stroke causes a “back pressure”
effect that leads to the stroke. These strokes can be either ischemic or
hemorrhagic. Some causes of venous stroke include severe dehydration, severe
infection in the sinuses of the head and medical or genetic conditions that
increase a person’s tendency to form blood clots.