What is Cerebral Ischemia?
The brain, like every other organ in the human body, needs nutrition and oxygen to function. These substances are carried by the blood through the blood vessels: the arteries carry the oxygenated blood, while the veins recover the blood rich in waste products.
When blood flow to the brain is blocked by an obstacle, the area that was previously properly perfused may not receive enough oxygen and nutrients. If this obstruction does not resolve quickly, spontaneously or through timely therapeutic intervention, then the brain tissue suffers. It is precisely when a part of the brain suffers from the "interruption" of the blood supply that we speak of cerebral ischemia.
In the most fortunate cases, the ischemia is only temporary and the related symptoms resolve spontaneously within the next 24 hours; in these cases we speak of transient ischemic attack or mini-stroke.
Other times the ischemia lasts for a long time and the symptoms last beyond 24 hours; in these cases we speak of a real stroke, one of the major causes of permanent disability and, in the most complicated cases, of death.
For this reason, the appearance of the first suspicious symptoms should lead to immediate medical attention.
Causes
As anticipated, cerebral ischemia is caused by a reduced blood supply to a more or less large area of the brain. The crucial event is the obstruction of a blood vessel which can be embolic or thrombotic.
In the first case, the ischemia is due to an embolus, usually a clot of blood that comes from other parts of the body, carried through the bloodstream. Usually, the emboli start from the heart or from atherosclerotic plaques present in the arteries that carry the blood to the brain, such as the carotids of the neck. Parts of the plaques can, in fact, detach and go to obstruct a cerebral artery smaller than the embolus itself.
In the case of thrombotic ischemia, however, the obstacle is a blood clot, called thrombus, which forms directly in the affected vessel. The thrombus, therefore, progressively narrows the lumen of the cerebral blood vessel, reducing the blood flow downstream of the obstruction.
Risk factors
It is above all cardiovascular pathologies, advanced age and an incorrect lifestyle that predispose towards problems of cerebral ischemia. The risk of thrombosis and atherosclerosis in particular contributes to smoking, incorrect nutrition, obesity and low physical activity.As for familiarity, it must be considered that generally the risk of suffering an ischemic attack is not inherited, but rather that of developing diseases that favor its onset, first of all arterial hypertension and diabetes.
Symptoms
The symptoms of cerebral ischemia depend on the damaged area, the extent of the affected area and the degree of reduction in blood flow. Nevertheless, it is possible to identify some traits common to the various types of ischemic attack. First, the symptoms always have the characteristic of arising suddenly or, in any case, within a few minutes. Patients with cerebral ischaemia may experience muscle weakness in one half of the body, loss of sensation or numbness in the arms or face, vision problems in one eye, or double vision. Other typical manifestations are the appearance of headaches, dizziness, problems with walking and maintaining balance, lack of coordination, difficulty in speaking and understanding the speeches of others. Sometimes, disturbances of consciousness may also be present, from drowsiness to coma.
Sometimes these symptoms disappear on their own within a short time and in any case within 24 hours. We then speak of a transient ischemic attack or TIA. If the ischemia persists for longer, however, it can be the cause of stroke, an event that causes major physical or intellectual problems, sometimes irreversible.
When to see a doctor
It should be clear by now that the "onset of" cerebral ischemia represents a real medical emergency. Even if the situation quickly returns to normal, it does not mean that the ischemic attack is not dangerous.
In most cases, a transient event signals that the circulation does not work as it should, so you are in a situation of risk for the development of a real stroke. For this reason, when the first symptoms appear, it is necessary to go to the emergency room, where a specialist doctor is able to detect the presence and severity of the ischemia, then direct the patient to the most appropriate therapy.
Diagnosis
From the diagnostic point of view, a cranio-encephalic CT scan is particularly useful, an examination that highlights hypodense areas in correspondence with the ischemic areas. The patient also undergoes tests such as blood pressure, blood oxygen, respiration and heart functioning.
Treatment
There is a specific treatment which, if administered within the first hours of the attack, allows to greatly limit the damage of the cerebral ischemia. This is the so-called thrombolysis: in practice, thrombolytic substances are administered intravenously, capable of dissolving one of the main components of the thrombus. In this way, the occluded blood vessel is freed and circulation can resume normally.
Among the most commonly used drugs we remember the tissue activator of recombinant plasminogen. Thrombolytic therapy should be carried out as soon as possible, because the more the hours pass, the more the risk of complications increases, in particular of secondary bleeding. Not only: after 6 hours. the drug is completely ineffective, so it is essential to intervene when the ischemic attack is still in the acute phase. Until recently it was believed that the maximum limit for proceeding with thrombolysis was even only 3 hours.
It is therefore essential to act as soon as possible, also to assess the need for surgery.
Prevention
Prevention of cerebral ischemias is possible by paying attention to predisposing factors.
If you are at risk, due to age or the presence of other pathological conditions, it is good to undergo periodic tests, such as a regular blood pressure check, a complete blood test, an electrocardiogram and an ultrasound of the blood vessels. In the presence of specific diseases, it is essential to follow the doctor's instructions.
When it comes to cerebral ischemia, it is very important to promote a healthy lifestyle, based on proper nutrition and regular physical activity. In fact, only 30 minutes of movement a day are enough to prevent most cardiovascular diseases. Quitting smoking is essential, as is giving up alcohol. The consumption of saturated fats should be drastically reduced because they favor the "increase of cholesterol levels in the blood, while the excess salt, as it is known, contributes to increase blood pressure.
Overall, these measures can greatly reduce the risk of cerebral ischemia. Also be careful to keep under control the problems that can increase the risk of cerebral ischemia, such as arterial hypertension and diabetes.
Those who have already suffered an ischemic attack, in addition to the indications listed above, should undergo periodic checks and strictly follow any pharmacological prescriptions, useful for reducing ischemic risk.
