transient ischemic attack
Introduction
Brief introduction to transient ischemic attack Transientcerebralischemicattacks (TCIA) is a transient, reversible neurological dysfunction caused by focal cerebral ischemia. The seizure lasts for a few minutes and usually recovers completely within 30 minutes. The neurological deficit is often left over 2 hours, or the brain ischemic signs are detected by CT and MRI. The traditional TCIA is defined within 24 hours. TCIA occurs well in 34 to 65 years old, accounting for 25.3% of people over 65 years old, more men than women. Sudden onset, mostly in the body position changes, hyperactivity, sudden neck rotation or flexion and extension, etc. There is no aura in the onset, there is a transient neurological localization sign, generally unconscious disorder, lasting 5 ~ 20min, can be repeated, but generally recovered within 24h, no sequelae. basic knowledge The proportion of illness: 0.006% Susceptible people: no special people Mode of infection: non-infectious Complications: Hypertension Diabetes Cervical spondylosis
Cause
Cause of transient ischemic attack
(1) Causes of the disease
Hypertension (35%):
Hypertension is currently recognized as the most important cerebrovascular disease, an independent risk factor for hypertension, regardless of age and gender, whether it is systolic or diastolic blood pressure, or an increase in mean blood pressure, no matter what causes High blood pressure is a risk factor for cerebrovascular disease. The brain is most susceptible to high blood pressure. The effect on the brain is caused by the effects of hypertension on cerebrovascular damage and stress itself.
(1) The degree of increase in blood pressure is directly proportional to the increase in the risk of cerebrovascular disease. If the diastolic blood pressure continues to be 12 kPa (90 mmHg), the risk of cardiovascular disease morbidity and mortality increases, and if the diastolic blood pressure is lowered to 12~ 14kPa (90 ~ 105mmHg), can reduce the risk of cerebrovascular disease by 35% ~ 40%, coronary heart disease events by 15% ~ 20%, intervention test proved that when systolic blood pressure 21.33kPa (160mmHg), antihypertensive treatment can To reduce the incidence of cerebrovascular disease, it is generally considered that the basal systolic blood pressure increases by 1.33 kPa (10 mmHg), the diastolic blood pressure increases by 0.66 kPa (5 mmHg), and the risk of cerebrovascular disease increases by 49% and 46%, respectively, in the past 20 years. American citizens have improved the treatment and control rate of hypertension, reducing the mortality rate of cerebrovascular disease by 60% and the mortality rate of coronary heart disease by 53%. These all prove that effective blood pressure reduction can reduce cardiovascular and cerebrovascular diseases (cerebrovascular disease and coronary heart disease). The prevalence of ).
(2) The relationship between the risk of cerebrovascular disease caused by hypertension and age and gender: The incidence of cerebrovascular disease increases with age. The data of urban and rural surveys in China indicate that the incidence rate of the 75-year-old age group is 1.6 times that of the 65-74-year-old group. It is 4 times that of the 55-64-year-old group, 8-9 times of the 45-54-year-old group, and 30-50 times of the 35-44-year-old group. The incidence of cerebrovascular disease and death are higher in men than in women. Western countries The ratio of male to female is 1.35:1. In 1985, the census result was the ratio of the standard incidence of cerebrovascular disease in men and women was 1.27:1.
(3) If patients with hypertension have other heart diseases, the risk of cerebrovascular disease will increase accordingly, such as left ventricular hypertrophy, abnormal fundus of the fundus, arrhythmia, etc., or when combined with hypertension on the basis of the original heart disease, such as In patients with rheumatic heart disease, myocardial infarction, and arrhythmia, the risk of cerebrovascular disease is also increased.
(4) The incidence and mortality of cerebrovascular disease are consistent with the geographical distribution of hypertension. The incidence of cerebrovascular disease in China is about 130/100,000 on average. The areas with high incidence are Heilongjiang, Jilin, Liaoning and Hebei. The provinces are consistent with the distribution of high blood pressure, and the incidence of cerebrovascular disease declines from north to south from high to low, and the city is higher than the rural.
Heart disease (27%):
Heart disease is the third risk factor for cerebrovascular disease, various heart diseases such as rheumatic heart disease, coronary atherosclerotic heart disease, hypertensive heart disease, congenital heart disease, and various heart types that may be complicated Damage such as atrial fibrillation, atrioventricular block, cardiac insufficiency, left heart hypertrophy, bacterial endocarditis, etc. These factors increase the risk of cerebrovascular disease by affecting hemodynamics and emboli. In particular, the risk of ischemic cerebrovascular disease.
Diabetes (25%):
10% to 30% of patients with recurrent ischemic cerebrovascular disease have a history of diabetes. The incidence of cerebrovascular disease in diabetic patients is about 10 times higher than that without diabetes. Diabetes not only causes microvascular disease, but also causes large Vascular lesions, which cause atherosclerosis and microcirculatory disorders, thereby promoting ischemic cerebrovascular disease.
(1) Diabetic patients with various types of hyperlipidemia due to insufficient or increased insulin, or normal serum lipid levels, abnormal lipoproteins (such as increased LDL) in transporting lipids can cause and promote atherosclerosis. Formed, LDL can be produced by foam cells to promote the formation of arteriosclerosis.
(2) Metabolic abnormalities of diabetes are mainly caused by insufficient insulin and increased blood sugar. Pathological manifestations of small arteriosclerosis in special organs are mainly manifested by extracellular changes - the appearance of glycated proteins and the increase of intracellular sorbitol concentration. In order to increase the osmotic pressure of cells, the function of cells decreases, protein denaturation occurs, and cataracts appear in the ocular tissues. These changes are all metabolic changes in the cells.
Cerebral atherosclerosis
Cerebral atherosclerosis is a part of systemic arteriosclerosis, gray-yellow plaque on the intima of the arteries, collagen fibers on the surface of the plaque continue to proliferate and smooth muscle cells containing lipids, causing narrowing of the arterial lumen, and even deep plaques of the fibers. The cells are necrotic, forming atheromatous plaques, the fibrous caps on the surface of atheromatous plaques are necrotic, ulceration forms ulcers, and necrotizing atherosclerotic plaques can be discharged into the bloodstream to cause embolism, and ulcers can hemorrhage to form hematoma, making small Arterial stenosis or even obstruction, the blood supply disorders, the main causes of atherosclerosis: high blood pressure, hyperlipidemia, smoking, diabetes, obesity, insulin resistance and other factors, the pathogenesis of atherosclerosis Such as lipid infiltration theory, intimal injury theory, receptor theory, middle layer smooth muscle cell hyperplasia theory, hemodynamics theory, etc., most scholars believe that the pathogenesis of atherosclerosis is complex, is a comprehensive long process .
2. Increased blood viscosity
Patients with increased blood viscosity, cerebral blood flow is relatively slow, so that the brain relative to ischemia and hypoxia, while hematocrit, fibrinogen, platelet aggregation, etc., can increase blood viscosity, cerebral blood flow decline, leading to microcirculation Obstacle, for the elderly can easily lead to the formation of cerebral ischemic attack or cerebral infarction, increasing the risk of cerebrovascular disease.
3. Hyperlipidemia
Among the population aged 15 to 69 years old who have undergone blood lipid examination, hyperlipidemia accounts for 40%. Cardiovascular and cerebrovascular diseases are mainly caused by atherosclerosis, and more than 80% of atherosclerosis is caused by hyperlipidemia. Hyperlipidemia is an important factor leading to atherosclerosis. Excessive lipid deposition in the arterial intima, intimal fibrous connective tissue hyperplasia, localized thickening, formation of atherosclerotic plaque, increased or increased plaque The wall of the tube is hardened, the lumen is reduced or occluded, causing ischemic damage to the blood supply site, and eventually dysfunction of various organs occurs.
4. Bad lifestyles such as smoking and alcohol abuse
(1) Smoking is a risk factor for various cerebrovascular diseases, especially ischemic cerebrovascular disease, and the daily smoking amount and duration are also proportional to the incidence of cerebrovascular disease. Long-term smoking can increase blood viscosity. The damage of blood vessel wall promotes the occurrence and development of cerebrovascular disease. Smoking can lead to an increase in cholesterol and triglyceride levels, and a decrease in high-density lipoprotein. This phenomenon is more pronounced in alcoholics at the same time.
(2) The incidence of cerebrovascular disease in alcoholics is 4 to 5 times that of the general population. It has been reported that ethanol poisoning has the same risk of promoting cerebrovascular disease as hypertension, diabetes, smoking, etc. High calories, excessive drinking can increase obesity, excessive drinking can increase the risk of cancer, cirrhosis, myocardial damage and sudden death, but a small amount of alcohol may reduce the risk of cardiovascular and cerebrovascular diseases.
5. Asymptomatic carotid artery disease
Vascular murmur in the neck is a dangerous indication for cerebrovascular disease. When coexisting with hypertension, the incidence of cerebrovascular disease is higher, and asymptomatic carotid murmur is about 5% of the population over 45 years old. And with the increase of age, cerebrovascular disease and carotid murmur are related, and the range of murmur is related to the location of cerebrovascular disease.
6. Obesity
Obesity is a disease, a dystrophic disease that is more common in people with better living conditions. It is caused by overnutrition. It is characterized by excessive body fat and adipose tissue, which exceeds normal physiological needs and is harmful to Good health, whether obesity can be used as a risk factor for cerebrovascular disease, the results of each study are inconsistent. Most scholars believe that obesity is mostly related to hypertension, diabetes, heart disease and other factors. It may work through these factors, so it may not be brain. Independent risk factors for vascular disease, obese patients not only have a higher mortality rate, but also have the potential for latent diabetes, atherosclerosis, hypertension, coronary heart disease and other diseases.
7. Age and gender
Old age and male are important independent risk factors for cerebrovascular disease. The incidence and mortality of cerebrovascular disease increase with age. With the increase of age, the incidence of cerebrovascular disease increases exponentially, and each increase is 5 years old. The incidence of cerebrovascular disease almost doubled, and the incidence of cerebrovascular disease was higher in men than in women by 30%. The incidence of postmenopausal cerebrovascular disease was significantly higher in women than before menopause.
8. Family history
People with cerebrovascular disease in immediate family members are at greater risk of cerebrovascular disease. Because of the high prevalence of hypertension, heart disease and diabetes in patients with cerebrovascular disease, the independent role of genetic factors itself is still For further study, it may be a polygenic hereditary disease.
9. Bad diet structure
Excessive consumption of animal fat, especially foods containing high cholesterol, high calorie, high sodium salt, low potassium salt, low calcium salt food, and irregular diet, etc., easily induce lipid metabolism disorders, water, electrolyte imbalance Occurrence of diseases such as obesity, hyperlipidemia, and high blood pressure.
10. Other factors
Such as vascular disease, oral high-concentration estrogen contraceptives, cold temperatures, lack of exercise, monotonous life, vascular headache, stress on frequent negative events, type A behavior, psychotic introversion and infection (especially Intracranial infections, etc., can increase the risk of cerebrovascular disease.
(two) pathogenesis
The pathological basis of transient ischemic attack (TCIA) is that the relative transient stenosis of the cerebral blood vessels is caused by specific causes, resulting in temporary impaired brain perfusion, and the brain tissue function of the supplied blood also appears. Reversible functional defects, due to the absence of complete blood supply blockage and the corresponding collateral circulation, so after the onset of disease factors, the brain function of this defect also recovered, the main mechanism is as follows.
1. Hemodynamics and abnormal blood components
Cerebral atherosclerosis and other causes can occlude or stenosis of the carotid artery and vertebral-basal artery system. At this time, in the state where the blood supply to the brain can only be barely maintained, if there is a collateral circulation disorder, for example, the patient suddenly occurs. Sexual blood pressure is too low, cerebral blood flow is reduced, which leads to the onset of TCIA. When the blood pressure rises and the collateral circulation recovers, the clinical symptoms disappear.
Therefore, some people think that the blood pressure drops too fast and the amplitude is too large, which is one of the causes of cerebral ischemia. However, due to the automatic regulation of cerebral blood circulation, when the blood pressure drops, the cerebral blood flow resistance also decreases, so the blood pressure drop does not necessarily affect the cerebral blood flow. Only in the cerebral artery stenosis, cerebral blood circulation automatically adjusts the disorder, and the blood pressure drops below the critical level.
In addition, various effects affect blood oxygen, blood sugar, blood lipids and changes in blood viscosity and coagulability and blood pathological conditions (erythrocytosis, leukemia, abnormal proteinemia, thrombocytopenia), and diseases affecting cardiac output such as Arrhythmia, atrioventricular block, myocardial damage, can also cause a sudden decrease in local blood flow to the TCIA predisposing factors, brain micro-arteries under the influence of long-term sputum and high-pressure mechanical shock, fibrous necrosis can occur The luminal obstruction, its dominant brain tissue can cause a ischemic attack due to a temporary interruption of blood supply.
2. Micro-embolism theory
The important pathogenesis of transient ischemic attack is the microembolism theory.
According to the theory, the wall thrombus of the internal carotid artery or vertebral-basal artery arteriosclerosis stenosis, the cholesterol crystals fall off, the hardened plaques fall off and the blood decomposed substances, platelet aggregates, etc. Blocking the brain artery, causing ischemic symptoms, due to the body's self-regulation, micro-thrombus in the blood vessels is a process of continuous production and continuous dissolution, especially in patients with cerebral arteriosclerosis, cholesterol plaques constantly Small debris is shed into the blood. These small particles are often transported into the same lower blood vessels in the laminar blood. When this small shedding does not pass through the tiny arteries, a small cerebral artery appears. Embolization, which is why patients with recurrent TCIA often show the same clinical signs. Because the causes of TCIA are mostly related to atherosclerosis, the microemboli of these atherosclerosis can come from the extracranial segment of the internal carotid artery. It can also be caused by pressure or damage to the neck artery (such as neck massage).
3. Cerebral vasospasm
Cerebral vasospasm is due to atherosclerotic plaque in the internal carotid artery system or vertebral-basal artery system. The stenosis of the lumen causes a blood flow vortex to maintain cerebral blood flow. When the blood flow vortex also accelerates, the area The arterial wall causes mechanical stimulation, resulting in transient cerebral ischemic attacks in the arteries of the arteries. When the vortex decelerates, the blood flow returns to normal and the clinical symptoms disappear.
4. Vascular factor theory
The neck artery is distorted, too long, and the knot or vertebral artery is compressed by the cervical vertebrae. When the head turns, it can cause TCIA.
Prevention
Transient ischemic attack prevention
Actively control the cause of TCIA, such as controlling blood pressure in patients with hypertension at a reasonable level, controlling blood sugar in diabetic patients, controlling heart attack and arrhythmia, reducing whole blood viscosity, hematocrit, plasma viscosity and platelet aggregation Sex, relieve vasospasm, and timely treat cervical spondylosis.
Complication
Transient cerebral ischemic complications Complications, hypertension, diabetic cervical spondylosis
Patients often have history of hypertension, diabetes, heart disease, cervical spondylosis, etc., so many clinical manifestations of primary disease, such as clinical manifestations of hypertension, clinical manifestations of diabetes, clinical manifestations of heart disease, etc.
Symptom
Transient ischemic attack symptoms Common symptoms Tripped double vision single eye suddenly appeared... Atherosclerosis monosodium sensation disorder Tinnitus Blood changes blood viscosity increased
Clinical type
(1) Transient internal cerebral ischemic attack of the internal carotid artery system: TCIA of the carotid artery system has less TCIA than vertebral-basal artery system, but it lasts for a long time and is easy to cause complete stroke. The most common symptom is single sputum. Hemiplegia, partial sensory disturbance, aphasia, monocular visual impairment, etc., may also occur in the same direction of hemianopia and fainting.
The main performance is:
1 Sudden black eyes suddenly appear in a single eye, or loss of vision, or white flicker, or visual field defect, or double vision, can be recovered in a few minutes.
2 The contralateral limbs were mildly partial or partial.
3 The dominant hemisphere is damaged by transient aphasia or misuse or loss of reading or loss of writing, or at the same time the facial muscles and the lingual muscles are weak.
4 occasional ipsilateral hemianopia, in which a sudden appearance of a single eye is a characteristic symptom of transient ischemic attack of the internal carotid artery system.
(2) Transient ischemic attack of vertebral-basal artery system: TCIA of vertebral-basal artery system is more common than TCIA of carotid artery system, and the number of episodes is also more, but the time is shorter, mainly manifested as brain stem, cerebellum and occipital lobe , temporal lobe and proximal spinal cord ischemia, neurological deficit symptoms.
The main symptoms are:
1 The most common symptoms are transient dizziness, nystagmus, standing or walking instability.
2 Transcendental vision into double or strabismus, blurred vision, visual distortion, visual field defect, etc.
3 transient dysphagia, drinking water cough, unclear language or hoarseness.
4 transient single or bilateral limb weakness, feeling abnormal.
5 transient hearing loss, medullary paralysis, cross sputum, hemiparesis and bilateral mild sputum.
6 Transient complete forgetfulness, manifested as loss of memory, but conscious, good writing and calculation skills.
7 a small number of conscious disturbances or trips.
The carotid system TCIA is more likely to develop complete cerebrovascular disease than the vertebrobasilar TCIA, and recurrent episodes, especially in the short-term recurrent episodes, are more dangerous. Most of the symptoms of the above two systems are incomplete, often appearing two Three symptoms, about 10% of patients with TCIA may have symptoms of both groups, and 10% to 75% of TCIA may occur after a few days of cerebral infarction.
(3) Special type of TCIA: In recent years, with the extensive clinical application of CT and MRI, it has been found that a large number of patients with TCIA have small focal cerebral infarction damage. Foreign scholars have reported that brain CT scans show low-density infarcts accounted for 10%. ~40%, and MRI examination can have up to 84% of brain parenchyma changes, so it is proposed that "cerebral infarction with transient signs (CTTS)" should be described as clinically consistent with TCIA, but brain CT Scanning or brain MRI showed a case of cerebral infarction.
2. Course of disease
Generally, about half of the carotid TCIA is diagnosed within 1 month. In 5 years, 25% to 40% of patients have complete cerebrovascular disease. The longer the history of TCIA, the greater the infarction, and the brain CT scan and brain MRI check for cerebral infarction. The more patients, about 25% of patients with cerebral infarction have a history of TCIA before the disease, about one-third of patients with TCIA attacks can naturally disappear or continue to attack.
3. Most scholars believe that TCIA is a precursor to cerebral infarction. Some scholars believe that TCIA is an ischemic cerebrovascular disease. People who have localized brain dysfunction lasting less than 24 hours belong to TCIA.
TCIA is a variant of cerebrovascular disease syndrome, which may be equivalent to transient cerebral ischemia without cerebral infarction or small infarction with rapid clinical recovery. A recurrent ischemic attack of a certain cerebral vascular may cause considerable cerebral infarction. Some patients with TCIA, if symptoms and signs persist for more than 24 hours, will be stabilized or partially recovered within the next few days, called complete stroke, and some patients can continue to progress after 24h, called progressive stroke, brain Infarction is a process from quantitative change to qualitative change. The internal capsule and its surrounding structure are the junction area of cerebral arterial blood supply. It is often in a state of low blood perfusion. In addition, the wall is rough and the lumen is narrow, which makes the penetrating artery easy to form. Thrombosis, and then lacunar infarction, if the infarct is found on the image, and is consistent with clinical TCIA, it can be diagnosed as cerebral infarction or multiple cerebral infarction. For TCIA episodes, brain CT scan can see cerebral infarction, which can be diagnosed. For cerebral infarction, TCIA type cerebral infarction, this indicates that TCIA has a very close relationship with cerebral infarction. In some patients with TCIA, CT scan and brain MRI can detect infarction. Therefore, brain CT scan diagnosis of cerebral infarction is the most common and most valuable imaging modality, it can be a clinically effective treatment to provide evidence, so patients who TCIA clinical diagnosis of brain CT scan should be carried out.
Examine
Examination of transient ischemic attack
Hemorheological examination showed mainly increased blood viscosity, plasma viscosity, hematocrit, fibrinogen and platelet aggregation rate.
1. Examination of risk factors for cerebrovascular disease: such as hypertension, diabetes, heart disease, atherosclerosis, etc.
2. Cerebrovascular examination: such as transcranial Doppler examination, carotid B-ultrasound, DSA, MRI, etc.
3. Cervical vertebra examination: cervical X-ray film, cervical CT scan or cervical MRI examination can be used.
4. Brain CT scan or brain MRI examination: mainly to rule out the diagnosis.
5. ECG or cardiac B-ultrasound: can be found in atrial fibrillation, frequent premature beats, old myocardial infarction, left ventricular hypertrophy, etc., echocardiography can have heart valve disease, such as rheumatic valvular disease, senile valvular disease.
Diagnosis
Diagnosis and diagnosis of transient ischemic attack
Diagnostic criteria
The diagnosis of transient ischemic attack mainly relies on detailed medical history, that is, sudden, repetitive, transient and stereotypical characteristics, combined with necessary auxiliary examination for diagnosis, and must be excluded after diagnosis of other cerebrovascular diseases. Main clinical features Yes:
1. Sudden, transient, episodes of focal neurological deficits.
2. Many of the above symptoms can be completely restored in a few minutes or hours. A few patients lasted for more than ten hours, but all returned to normal within 24 hours without neurological sequelae.
3. The main symptoms of focal neurological deficit are:
1 The symptoms of internal carotid artery system are: hemiplegia, partial numbness, feeling fading, visual impairment,
2 vertebral-basal artery symptoms are: dizziness, headache, tinnitus, black eyes, facial numbness, limb weakness, drinking water cough, unclear.
4. The above symptoms can be repeated.
5. There may be risk factors for cerebrovascular disease: such as atherosclerosis, hypertension, diabetes, hyperlipidemia, heart disease and other medical history.
6. There are no signs of nervous system during the episode.
7. Brain CT scan, brain MRI can not confirm the evidence of cerebrovascular disease.
Differential diagnosis
TCIA should be differentiated from focal sports epilepsy, inner ear vertigo and syncope episodes.
Focal sports epilepsy
It should be differentiated from the internal carotid artery type TCIA. Most of the focal sports epilepsy are brain organic lesions, which are more common in young people. Most of them are a series of repeated twitching movements on one limb or part of the body, mostly on one side. Oral angles, eyelids, fingers or toes may also involve the side of a face or the distal end of a limb. After a more severe episode, the site of the attack may leave a temporary affected muscle spasm, that is, Todd's palsy, which may occasionally last for several hours. , several days, even weeks, it is a continuous partial epilepsy, a history of seizures, a brain CT scan or MRI can find brain lesions, EEG has epilepsy waves, anti-epileptic drugs can control seizures, For identification, the electroencephalogram of the internal carotid artery type TCIA was normal, and the duration of the attack was less than 24 hours.
2. Inner ear vertigo
Should be identified with vertebral-basal artery TCIA, the common point is that there are dizziness, but more common in TCIA elderly, inner ear vertigo is more common in the middle, young people with tinnitus, inner ear vertigo episode lasts for a long time, can reach several days, after Gradually relieved, neurological examination has no local signs, especially no signs of brain stem positioning, mannitol and symptomatic treatment are effective.
3. syncope episodes
The syncope episode is more common in young women. It refers to the sudden transient loss of consciousness. It is temporary, and the transient loss of consciousness caused by extensive cerebral insufficiency is often caused by physical factors such as hypoglycemia, alkalosis and brain. The tissue itself is caused by injury, and it can also be secondary to the blood circulation disorder of the brain. Its clinical features are acute onset, transient loss of consciousness. Patients often have prodromal symptoms about 1 minute before the onset of syncope, showing general discomfort and blurred vision. , tinnitus, nausea, pale, cold sweat, limb weakness, followed by rapid syncope, casual motion and loss of sensation, sometimes apnea, slow heart rhythm, and even cardiac arrest, difficult to reach the radial artery The pulsation of the carotid artery, the clinical manifestations of pale, loss of consciousness and sudden collapse are typical manifestations, often accompanied by dizziness, vertigo, nausea, weakness, cold sweat and other aura symptoms, generally lasting 2 to 3 minutes, followed by all The function gradually recovers. After the patient wakes up, there may be a short period of conscious turbidity, abdominal discomfort, nausea, vomiting, and even size. Incontinence, extreme fatigue, lethargy, duration of a few minutes to half an hour, after the onset of examination can be no positive signs, and TCIA episodes are more common in the elderly, the duration of the attack is less than 24h, the cause of the attack can be more in the body position change, hyperactivity, The neck suddenly turns or bends and stretches, etc., the disease has no aura, and generally there is no consciousness disorder.
