Stroke & Neurointervention Foundation

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Home :: Stroke :: Types of Stroke
Type of Stroke
A stroke is classified as either hemorrhagic or ischemic. Approximately 83% of strokes are ischemic, resulting from a blockage in a cranial artery. The remaining 17% are hemorrhagic strokes in which a cranial blood vessel has burst.

Ischemic Stroke:
Ischemic StrokeIschemic stroke refers to the condition that occurs due to the blocking of a brain artery. The functioning of the brain depends on the supply of oxygen and nutrients brought to its various parts by arteries from the heart. If any of these arteries is blocked, the brain cells (neurons) corresponding to its region of supply will be deprived of the oxygen and will not be able to sustain life for long. This is why immediate medical attention is absolutely mandatory.

Ischemic stroke can occur due to several different kinds of diseases. The most common cause is narrowing of the arteries in the head and neck region due to atherosclerosis, or gradual cholesterol deposition. If the blockage becomes too critical, blood cells may start aggregating and form blood clots. These clots can block that artery (thrombosis), or can dislodge and migrate to other arteries closer to the brain (embolism).

Another cause of stroke is blood clots originating in the heart caused by some disease or as a result of irregular heartbeat (arrhythmias), heart attack, or abnormalities of the heart valves. A few uncommon causes of such stroke include use of drugs, trauma to the blood vessels of the neck due to accident, or disorders of blood clotting.

Ischemic StrokeDepending upon the location of the damage, patients can lose sensory, motor, or reasoning abilities. In the most drastic cases, the patient is severely disabled; incapable of performing common, everyday tasks. Ischemic strokes frequently occur in the largest intracranial arteries, which carry blood flow to more than 30% of the brain. These include the middle cerebral, anterior communicating, and internal carotid arteries. A major blockage in one of the arteries is a significant, life-threatening event.

Hemorrhagic Stroke::
Hemorrhagic StrokeHemorrhagic strokes are caused by ruptured blood vessels in the brain. These strokes occur when an Arterio-Venous Malformation (AVM)/Arterio-Venous Fistula (AVF), an aneurysm, or a blood vessel bursts, causing uncontrolled bleeding in the brain. This bleeding has two morbid consequences:.
  1. First, brain tissue downstream from the burst can be deprived of oxygenated blood.
  2. Second, free blood in the brain tissue triggers a biochemical reaction that can cause permanent damage
The patient can suffer temporary or permanent mental impairment or, if life-sustaining functions such as breathing are involved, death. Hemorrhagic strokes are difficult to treat and are more likely to be fatal.

Hemorrhage can have certain delayed effects as well.
  • Arterial VasospasmArterial Vasospasm: It typically appears about 3 to 4 days after rupture/bleed and reaches a peak in its incidence and severity in the second week post SAH. However, it is observed that only 40% to 70% of patients have evidence of this Vasospasm out of which only 20% to 30% develop the clinical symptoms. The symptoms of vasospasm typically begin 4 -5 days after the hemorrhage. They are:
    1. an onset of confusion
    2. decreasing level of consciousness
    3. in severe arterial narrowing these symptoms may progress to focal neurological deficits, infarction, coma and even death.
In less severe cases, neurological recovery can be expected as the arterial narrowing resolves.
  • HydrocephalousHydrocephalous: Sometimes there is a build-up of the fluid in and around the brain and spinal cord (hydrocephalus); this causes generalised headache and problems with higher mental functions and memory, and with a problem in balance. Occasionally epileptic fits may occur, but these can be controlled with medication. A small operation to insert a tube (shunt) can be performed to drain the excess fluid.


Read More.
  • Types of stroke
  • Risk factors
  • Tests
  • Treatment options