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Sudden blackness in front of eyes may be carotid artery stenosis
Sudden blackness in front of eyes may be carotid artery stenosis. DSA is the “gold standard” for diagnosing carotid artery stenosis. Unlike CT and MR examinations, DSA is an invasive examination that requires hospitalization to be completed under local anesthesia in the operating room.
General conditions of carotid artery stenosis
Carotid artery stenosis refers to the stenosis and occlusion of the common carotid artery and internal carotid artery that can cause stroke or transient ischemic attack. It’s like traffic jams on the main roads. One of the causes of blood vessel stenosis is the accumulation of plaques in the blood, which is a kind of deposits that appear in the blood. This cause is called “atherosclerosis” in medicine.
Medically, atherosclerosis is the main cause of carotid artery stenosis, accounting for more than 90%. Other diseases, such as dissecting aneurysm, fibromuscular dysplasia, arteritis, etc. can also cause carotid artery stenosis. Currently, 1/3 of adults in China have carotid atherosclerotic plaque. Among the 70-89 year-old people, the number of people with carotid artery plaque is as high as 63%.
According to this situation, the narrow blood vessel walls will become narrower and narrower. The blood vessels, the “highway” of the human body, are facing more and more serious traffic congestion, and even completely obstructed blood flow. This is called As “occlusion”. At this time, it is easy to induce stroke. Stroke occurs because the brain loses its normal blood supply. Although only a few minutes, the brain cells will soon begin to die. Therefore, stroke is one of the diseases with very high mortality and disability rate.
The carotid artery is a large blood vessel that carries oxygen-carrying blood from the heart to the head, face, and neck. It is one of the main blood vessels for the brain. Therefore, the stenosis of the carotid artery will lead to insufficient blood and oxygen supply to the brain. The brain, the “CEO” of the human body, is already malnourished, and other parts of the body will become more passive.
In patients with severe carotid artery stenosis, even with effective drug treatment and control, the incidence of cerebral ischemia events within 2 years will be as high as 26%; and more than 60% of cerebral infarctions are caused by carotid artery stenosis, and severe cerebral infarction can even be Lead to disability and even death of the patient. Therefore, carotid artery stenosis has become a “number one killer” that endangers people’s health in today’s society, and people have to pay attention and beware of it.
The pathogenesis and clinical symptoms of carotid artery stenosis
Hypertension, hyperlipidemia, diabetes, and smoking are all the culprits that cause carotid artery stenosis, especially the “terrorist” of hypertension. Therefore, one of the key points of prevention is to control blood pressure. Maintaining blood pressure within the normal range will effectively alleviate cerebrovascular diseases induced by carotid artery stenosis. At the same time, encouraging smoking cessation can also play a role in preventing corresponding symptoms caused by carotid artery stenosis.
So now, what symptoms will indicate carotid artery stenosis? First of all, we must understand that carotid artery stenosis is divided into asymptomatic carotid artery stenosis and symptomatic carotid artery stenosis. This requires us to understand it in two parts.
Patients with asymptomatic carotid artery stenosis have only mild headaches or dizziness. In the early stage, there are mostly no symptoms. Occasionally, there may be sudden dizziness and headache, numbness of the limbs, transient blindness, or the tongue is not listening and unable to speak. Most of these symptoms disappear quickly, and most patients recover within a few minutes, so it is less likely to attract attention.
Such symptoms are mainly due to cerebral ischemia, which can be manifested as a short-term blackout on the side of the carotid artery stenosis or loss of vision (that is, the feeling of sudden blackness in front of the eyes, blurred invisible things), and physical activity Inflexible performance. In severe cases, it can be manifested as cerebral infarction, causing corresponding symptoms, signs and imaging features such as hemiplegia, aphasia, cranial nerve damage, coma, etc. on the opposite side of the lesion.
Because such symptoms are not obvious and difficult to detect, they can be extremely dangerous when they appear under certain circumstances, such as driving, dangerous underground operations, and high-altitude operations, once they have blurred thinking, transient blindness, etc. , It is likely to cause serious danger to life. Therefore, we must be vigilant and pay special attention to these symptoms.
So after a little understanding of the manifestations of asymptomatic carotid stenosis, I believe everyone has the next question, what about symptomatic carotid stenosis?
Symptomatic carotid artery stenosis refers to the occurrence of one or more of the following symptoms in the past 6 months:
1. Transient ischemic attack;
2. Transient amaurosis: refers to sudden loss of vision, lasting from a few seconds to several hours, which is a characteristic symptom of carotid artery stenosis;
3. Mild strokes and non-disabling strokes caused by intracranial blood vessels on the affected side.
Once the above symptoms appear, whether they are mild or severe, we must pay close attention to them. Then do the corresponding examination with the doctor.
Diagnostic tests for carotid artery stenosis
All patients with carotid artery stenosis must undergo a physical examination of the nervous system, which is to make a further diagnosis based on the state of expression, whether the face is symmetrical, language, consciousness, motor function, limb tension, ataxia test, sensory function, etc., some patients may When the signs of stroke are detected, the doctor will also perform carotid ultrasound examination, CT angiography (CTA), nuclear magnetic examination, cerebrovascular angiography, etc. to determine the exact location and degree of carotid artery stenosis. These operations sound very complicated. Let’s have a general understanding of how these professional diagnostic methods are performed.
Ultrasound examination is the first choice for clinical screening of carotid artery stenosis. It can diagnose the location and degree of arterial stenosis or occlusion. Moreover, ultrasound inspection is a non-invasive inspection with low cost and repeatability. The disadvantage is that multiple stenosis cannot be accurately quantified, and the degree of stenosis may be overestimated.
Magnetic resonance examination
Magnetic resonance imaging angiography (MRA) can show the anatomical location and degree of carotid artery stenosis, but if the patient has a ferromagnetic metal implant, such as a pacemaker, it is not suitable for this examination .
CT examination includes coronary CT examination (CTA) and CT perfusion scan examination (CTP). CTA can provide information on the anatomy and morphology of the aortic arch, the opening of the vessel on the arch, and the carotid artery, and evaluate the degree and location of the carotid artery stenosis. CTP can obtain perfusion information of blood flow in the brain.
Whole cerebral angiography (DSA) examination
DSA is the “gold standard” for diagnosing carotid artery stenosis. Unlike CT and MR examinations, DSA is an invasive examination that requires hospitalization to be completed under local anesthesia in the operating room. DSA examination can help to observe the type of aortic arch, the nature of carotid artery stenosis, such as the location of the stenosis, the degree of stenosis, the overall shape of the plaque, or whether the plaque has ulcers. It can also observe the contralateral carotid artery, vertebral artery and intracranial Willis. Integrity of the ring, etc. If the patient is likely to undergo interventional therapy, non-invasive examinations such as CT are the first choice. After admission, angiography is performed to determine the location and nature of the lesion, and then interventional therapy is performed at the same time.
Here to introduce to you, according to the DSA results, the degree of carotid artery stenosis is divided into 4 levels according to the NASCET method (North American symptomatic carotid endarterial exfoliation test method), which are:
1. Mild stenosis is a reduction of the inner diameter of the artery <30%;
2. Moderate stenosis is a 30%-69% reduction in the inner diameter of the artery;
3. Severe stenosis is a 70%-99% reduction in the inner diameter of the artery;
4. Complete occlusion is the state before occlusion, and the degree of stenosis is >99%.
Based on these professional diagnoses, medical staff can more accurately grasp the condition of the disease, so as to carry out further diagnosis and treatment.
(source:internet, reference only)