Today we begin to talk about stroke, a pathology that in Italy represents the third cause of death, after cardiovascular diseases and neoplasms. It also represents one of the main reasons for disability.
Stroke literally means "blow". In fact, symptoms come on suddenly, violently, often without warning signs. Stroke is a disease that affects the brain due to a circulatory problem. In practice, it appears when there is an interruption in blood flow in a more or less extended area of the brain; this reduction in blood supply can be linked to the presence of an obstacle, such as a blood clot, or to the rupture of a cerebral vessel. In the first case we speak of ischemic stroke, in the second of hemorrhagic stroke. Whatever the cause, the area of the brain deprived of the correct blood supply suffers. Without the necessary oxygen and nutrients, the brain tissue cannot carry out its activity, nor remain vital: the arrest of blood flow even for a few minutes can cause the death of brain cells, which do not have great capacity to regenerate. For this reason, the activities controlled by the damaged area of the brain will be lost, often irretrievably. The affected person can therefore report a condition of physical disability or difficulty even after having overcome the stroke. In other cases, the outcome is unfortunately fatal. .
Clearly, stroke symptoms vary based on the location and extent of the damaged brain area; however, unlike other neurological disorders, these symptoms always have the characteristic of onset abruptly, without warning. Stroke can cause characteristic symptoms: weakness, sudden loss of sensation or paralysis in one part of the body; difficulty finding words or understanding what others are saying; paralysis of part of the face; sudden vision problems; loss of balance, dizziness and lack of coordination. Recognizing the signs of stroke is essential, because you need to intervene as quickly as possible. In fact, there are specific treatments which, if adopted shortly after the onset of symptoms, allow the damage to be greatly limited.
As anticipated, stroke can result from ischemia or haemorrhage. Let's see what characteristics allow us to distinguish these two different events. Ischemic stroke is the most common type of stroke. In fact, in the vast majority of cases, the disease depends on the sudden closure of a blood vessel that prevents the normal passage of blood. This leads to ischemia. Most of the time, the blockage of blood flow is the consequence of an atherosclerotic plaque that has gradually formed in a cerebral vessel, growing up to occlude it; in other cases, the same plaque can suddenly rupture leading to the sudden formation of a blood clot, called thrombus, which occludes the affected vessel. In still other cases, the obstruction can be caused by blood clots that have formed in other parts of the body, such as the heart; these clots, detaching from the original site are called emboli and are thus pushed by the blood flow towards the brain; if they are not dissolved in time by the body's defensive mechanisms, these emboli literally plug lower-caliber blood vessels. The other form of stroke, hemorrhagic stroke, occurs in the event of a rupture of a blood vessel in the brain. This type of damage, in turn, can result from a sudden and significant increase in blood pressure or the presence of a malformation of the vessel wall itself, as happens, for example, in the case of a cerebral aneurysm. Even the same atherosclerotic plaques, however, help to stiffen the walls of the blood vessels, facilitating their rupture. In the case of a hemorrhagic stroke, the cells of the brain suffer not only from the interruption of the supply of oxygenated blood, but also from the pressure exerted by the blood leaking from the lesion, which accumulates by compressing the surrounding area. Hemorrhagic stroke is much less frequent than ischemic stroke, but, as is easy to imagine, it is associated with higher short-term mortality. Sometimes, the actual stroke is preceded by symptoms that closely resemble those of the stroke, with the only difference being reversibility; these symptoms, in fact, disappear spontaneously within a few minutes or hours. In these cases we speak of a transient ischemic attack, a kind of "mini-stroke" that occurs when the blood supply to the brain is interrupted only for a short period of time. As we saw in a previous video, transient ischemic attack can be a wake-up call for a full-blown stroke, so it should never be underestimated. As soon as something strange is felt, it is advisable to alert 118 as soon as possible. In fact, it is not possible to know in advance whether it is a transient ischemic attack or a stroke.
Risk factors that increase the likelihood of suffering a stroke include atherosclerosis first. It is a narrowing of the arteries due to the formation of deposits rich in fat in them. The main cause of this disease is too high a level of LDL cholesterol in the blood, the so-called "bad cholesterol", which can accumulate on the walls of the blood vessels that carry blood to the brain. In the long run, atherosclerotic plaques - also made up of white blood cells, calcium, and scar tissue - can thicken and block circulation. In addition, small fragments can detach from these plates and close the smaller cerebral vessels. Other cardiovascular diseases, such as heart rhythm abnormalities - particularly atrial fibrillation - can also promote the formation of emboli directed to the brain. In addition to atherosclerosis, arterial hypertension also plays a crucial role: it can in fact promote ischemia and ruptures of the vessels. The risk of stroke increases significantly even in the presence of diabetes, since the disease damages blood vessels throughout the body, including the brain. Other minor causes of stroke are blood clotting defects and a previous heart attack, which, if not treated properly, increase the likelihood of a stroke.
Several factors can increase the risk of suffering a stroke. Some of these cannot be changed, as in the case of age, sex and family predisposition. Stroke is more common after 55 years of age and the risk doubles after every decade. Furthermore, men are more affected than women, although the risk tends to level off after menopause, becoming even higher for women over 80 than men of the same age. Let's now see what are the main modifiable risk factors. First, the risk of stroke increases in smokers. In fact, smoking is a terrible enemy of blood vessels. Just to give a few examples: it promotes hypertension, the accumulation of plaques in the arteries and decreases the oxygenation of the blood and organs. An incorrect diet can also favor the onset of a circulatory problem. In particular, a diet excessively rich in saturated fat is linked to an increase in bad cholesterol in the blood, while an excess of salt promotes an increase in blood pressure. Excessive alcohol consumption, obesity and a sedentary lifestyle are additional risk factors for the occurrence of a stroke. The use of oral contraceptives also appears to be associated with an increased risk of stroke in women. All of these modifiable factors we have just listed are susceptible to preventive action, but we will discuss this in more detail in the next episode.
