Different Kinds Of Strokes

Different Kinds Of Strokes

Ischemic Stroke
It is estimated that roughly 80% of strokes, fall under the category of ischemic stroke. It can happen due to the blockage in the large blood vessels on the brain surface or in smaller blood vessels within the brain. The former is normally referred to as large-vessel infarcts while the latter is called small-vessel infarcts.

Some of the other types of ischemic strokes are embolic infarct, lacunar infarct and thrombotic infarct. Around 30% of ischemic stroke instances are due to infarcts of unknown reasons.

Embolic infarct: It occurs when a blood clot formed in any part of the body is carried through the blood where it gets stuck in the blood vessels thereby hindering the blood supply to the brain, which in turn results in the death of brain tissues.

If the blood clot is formed in the heart it is referred to as cardiac embolism, which is responsible for approximately 20-30% of ischemic strokes.

Thrombotic infarct: If an arterial blood clot is formed, blood supply to the brain will be obstructed causing tissue death, which results in Thrombotic infarct. Roughly about 10-15% of cases fall under this type. It has a slow progression and is mainly caused by the deposition of plaque in the arteries, which is known as atherosclerosis.

Lacunar infarct: Is caused when the blockage in the arteries is due to high blood pressure. Approximately 20% cases are of this type.

A transient ischemic attack (TIA): It is a temporary phase which might cause ischemic stroke in some. In a TIA, though an arterial obstruction is formed in the brain, it gets resolved on its own without any permanent tissue death.

But it is seen that 40% of patients with TIA history will suffer a stroke in future and in 10% cases a TIA was always followed by an ischemic stroke.

Hemorrhagic Stroke
Hemorrhagic strokes occur due to the bleeding caused by the rupture of blood vessels in the brain. As a result of this the oxygen supply to the surrounding tissues are cut off, which in turn results in stroke. It can be life threatening as it severely affects a large portion of the brain.

Intracranial hemorrhages are caused due to the rupture of blood vessels running between the brain and the skull. This is caused by traumatic brain injury (TBI), arteriovenous malformation, aneurysm or due to blood vessel weakness.

Epidural hematoma develops due to blood deposition between the outer membrane and the skull.

Subdural hematoma: develops when blood is deposited between the dura and the middle layer; this condition might worsen due to the shrinkage of brain due to ageing.

Traumatic injuries to the skull might also cause acute subdural hematoma, which can be life threatening.