Nowadays we must and can make the first necessary specification regarding the causes of this oxygenation deficit. In the case of the acute ischemic stroke (AIS) the stakes are much. The stroke can indeed be:
In this case, the damage is produced by the rupture of a cerebral artery with consequent blood-shedding. The hemorrhagic stroke, or more commonly the cerebral hemorrhage, is a dramatic event that however represents a minimum percentage of all the strokes that occur among the population, with an incidence of about 15%. Unfortunately, it is also the most lethal type: in about half of the cases, the outcome is the death of the person affected.
Also called cerebral infarction, this type of stroke, on which we will focus attention, is caused by the occlusion of one or both carotids, or arteries that carry oxygenated blood to the brain. Cerebral ischemia at the origin of this occlusion causes about 85% of all recorded strokes and can be more or less severe. In many cases, thanks to a timely intervention, it is possible to limit the damage to the brain and through an appropriate rehabilitation, the affected person can recover all his brain faculties.
We define stroke as the damage produced by the lack of oxygenation of a part of the brain which is in turn caused by the rupture of an artery with a blood spill cerebral hemorrhage or hemorrhagic stroke or by the blockage of one or more cerebral arteries cerebral ischemia. However, ischemia is also a vascular event that can have different causes, and in fact is divided into two main types: thrombotic ischemia and embolic ischemia. Let’s try to deepen it better.
Two Types of Ischemia
Now that we understand the difference between stroke and ischemia, we focus on the second and see how it is characterized. To understand the gravity of this vascular problem we must keep in mind that our brain needs to be constantly replenished with fresh blood in order to function at its best and that this happens thanks to the fundamental contribution of the arteries that connect it to the heart and lungs.
The blood that reaches the brain is not limited to delivering nutrients and oxygen to the brain cells, but at the same time charges with carbon dioxide and other waste products of cellular metabolism and carries them away, back to the heart.
The consequence would be the atrophy of neurons, which would no longer be able to function as they would need energy. If a cerebral artery becomes occluded, or an impediment is created whereby the blood can no longer flow into the brain tissue, and if this happens for a time longer than a few minutes, the neurons die. This is the reason why cerebral ischemia leads to stroke and to the brain damage we know well.
Thrombotic cerebral ischemia:
In this case, the lack of blood supply occurs directly in the brain, where one or both arteries, obviously damaged, are obstructed by a thrombus, a blood clot. This type of ischemia is also referred to as cerebral thrombosis and represents about half of the total cases of ischemic events in the brain. Moreover, it can, in turn, be divided into two types depending on the area of the brain in which the thrombosis occurs.