What is a stroke?
A cerebrovascular accident (CVA) or stroke, is a failure of blood circulation that affects a region more or less of the brain . It occurs as a result of obstruction or rupture of a blood vessel and causes the death of nerve cells, which are deprived of oxygen and nutrients essential to their functions. For the majority of people, there is no sign of a crisis. However, several risk factors can be monitored.
To read: the signs of the avc and its symptoms
Stroke has very different consequences. More than half of the people still have sequelae. Approximately 1 out of 10 individuals recover completely.
The severity of the sequelae depends on the region of the affected brain and the functions it controls. The larger the oxygen deprived area, the greater the risk of sequelae. As a result of a stroke, some people will have difficulty speaking or writing (aphasia) and memory problems . They may also be affected by a more or less important paralysis of the body.
The signs of avc, a medical emergency
When the nerve cells are deprived of oxygen, even for a few minutes they die; they will not regenerate. Also, the shorter the time between stroke and medical management, the greater the risk of serious sequelae.
Whatever the damage caused by oxygen deprivation, the brain has some adaptability. Healthy nerve cells sometimes succeed in taking over dead cells if stimulated by various exercises.
causes of Cerebral Vascular
Atherosclerosis, the formation of lipid plaques on the walls of blood vessels, is one of the main causes of stroke. Hypertension is also a major risk factor. Over time, the abnormal pressure exerted by the blood on the walls of the blood vessels can cause them to rupture. The rupture of an artery in the brain can be facilitated by the presence of an aneurysm . The aneurysm is a swelling of a small section of an artery, due to a weakness of the wall.
It is not always possible to determine the exact cause of a stroke. It is important, however, that physicians search for it by conducting various examinations to reduce the risk of recurrence.
With advances in prevention, the prevalence of stroke has declined dramatically in recent decades. Since the 1990s, however, it appears to be stabilizing.
Even today, more than 50,000 people in Canada suffer a stroke each year and about 14,000 die from it. Although strokes are rarer than heart attacks, they are still the third leading cause of death in Canada and a major factor in disability.
Three-quarters of stroke occurs in people aged 65 years and older . In Canada and North America, in general, they affect women more than men. Young children may also suffer, but this rarely happens.
There are three types of stroke: the first two are caused by the blockage of a cerebral artery ( ischemic stroke ). They are the most frequent and represent about 80% of strokes. The third is caused by a cerebral haemorrhage ( haemorrhagic accident ):
Cerebral thrombosis. It accounts for 40% to 50% of cases. It occurs when a blood clot forms in a cerebral artery, on a plate of lipids (atherosclerosis);
Cerebral embolism. It accounts for about 30% of cases. As in the case of thrombosis, a cerebral artery is blocked. However, here the clot that blocks the artery was formed elsewhere and was transported through the bloodstream. It often comes from the heart or from a carotid artery (in the neck);
Cerebral hemorrhage. It accounts for about 20% of cases, but it is the most severe form of stroke. Often caused by long-standing hypertension, it can also result from the rupture of an artery in the brain where an aneurysm is located .
In addition to depriving one part of the brain of oxygen, the hemorrhage destroys other cells by exerting pressure on the tissues. It can occur at the center or periphery of the brain, just beneath the cranial envelope.
Other rare causes of cerebral haemorrhage include seizures of hypertension, hemorrhage in a brain tumor, and blood clotting problems.
It may happen that the obstruction of a cerebral artery is only temporary and that it is absorbed naturally, without leaving any sequelae. This phenomenon is called transient ischemic attack (TIA) or mini-stroke . The diagnosis is confirmed by MRI . The symptoms are the same as those of a “true” stroke but disappear in less than an hour. A mini-stroke is a warning signal to be taken seriously: it may be followed by a more severe stroke within 48 hours. It is therefore important to consult a doctor as soon as possible.