Our brain
The human brain weighs 1200~1500g, which is 2% of body weight. It is estimated that 15% of the heart output is supplied to the brain, and the adult brain oxygen consumption accounts for 20% of the whole body oxygen supply, and the infant brain oxygen consumption can reach 50% of the whole body oxygen supply, and the brain sugar consumption accounts for 25% of the whole body sugar supply. The blood flow through the human brain reaches 800ml per minute, or nearly 50ml/100g/min.
The brain requires a large blood supply for its activities, and its source of energy is provided by the oxidative metabolism of glucose to produce ATP. Under normal conditions, a conscious person consumes approximately 160 micromoles of oxygen and 30 micromoles of glucose per minute per 100 grams of brain tissue. Unlike muscle and other tissues, the brain does not store much glucose, glycogen, or other high-energy phosphates (ATP, creatine phosphate), so it depends on a large, well-regulated blood flow to meet the brain’s immediate energy needs.
Blood supply to the brain
The brain receives its blood supply through four major arterial trunks: the left and right internal carotid arteries and the vertebral arteries.
The internal carotid artery divides into the ophthalmic artery, the anterior choroidal artery, and the anterior and middle cerebral arteries. The anterior cerebral artery supplies cortical areas including the motor and sensory cortices of the lower extremities, the supplementary motor cortex, and the urinary centers located in the paracentral lobule, along with a number of penetrating arteries. The middle cerebral artery provides blood flow to most of the lateral aspect of the cerebral hemispheres, including the major motor and sensory cortical areas, the optic radiations, the auditory cortex, and the language areas of the dominant hemisphere; the middle cerebral artery also gives off the doublestem artery.
The vertebral artery starts from the subclavian artery, travels up through the transverse foramen of the 6th cervical vertebra to the circumflex vertebra, passes through the foramen magnum and crosses the dura mater into the skull. Both vertebral arteries form the basilar artery at the junction of the medulla oblongata and the pontocerebellum, and divides into the left and right posterior cerebral arteries at the junction of the pontocerebrum and midbrain, providing blood supply to the lower temporal lobe and occipital lobe. The posterior inferior cerebellar artery divides from the vertebral artery to supply blood to the posterior inferior part of the cerebellar hemisphere, and the basilar artery branches include the internal auditory artery, the anterior inferior cerebellar artery, and the superior cerebellar artery to supply blood to the superior part of the cerebellum.
The anterior cerebral arteries on both sides pass through the anterior communicating artery and the middle cerebral artery on each side and the posterior cerebral artery through the posterior communicating artery to form the Willis loop at the base of the brain, so that the major arteries of the brain are interconnected to form an adequate collateral circulation.
What is cerebrovascular disease
Cerebrovascular disease is a neurological disorder caused by pathological changes in the blood vessels supplying blood to the brain (sudden interruption of blood flow such as thrombosis or embolism, rupture of cerebral vessels, damage to the vessel wall or changes in permeability, increased blood viscosity, etc.), mainly manifested by the occurrence of sudden focal neurological deficits (such as hemiplegia, aphasia, visual deficits and impaired consciousness).
Dangers of stroke
The incidence of stroke in China is about 89.6/100,000-314/100,000 for men and 76.7/100,000-212.2/100,000 for women, and the mortality rate of stroke is about 4-6 times higher than that of acute heart attack. Statistics show that the direct medical cost of ischemic stroke was 6,801 yuan per case in 1999, rising to 10,489 yuan in 2000. the economic burden of disease for ischemic stroke was 12.6-19.6 billion yuan in 2000.
Risk factors for cerebrovascular disease
The presence of multiple risk factors increases the susceptibility to cerebrovascular disease, of which hypertension, heart disease, atrial fibrillation, diabetes, smoking and hyperlipidemia are particularly important, while systemic diseases causing hypercoagulable states and the use of contraceptive drugs and alcohol are also associated with the development of cerebrovascular disease.
What is hypertension
Hypertension is defined as a sustained increase in systolic and/or diastolic blood pressure in the arteries of the body circulation. A systolic blood pressure ≥ 140 mmHg and/or a diastolic blood pressure ≥ 90 mmHg is diagnosed as hypertension.
Definition and classification of blood pressure levels (WHO/ISH)
Class Systolic blood pressure (mmHg) Diastolic blood pressure (mmHg)
Ideal blood pressure 〈120 〈80
Normal blood pressure 〈130 〈85
Normal high value 130-139 85-89
Grade 1 hypertension 140-159 90-99
Subgroup: Critical hypertension 140-149 90-94
Grade 2 hypertension 160-179 100-109
Grade 3 hypertension ≥180 ≥110
Simple systolic hypertension ≥140 〈90
Subgroup: critical systolic hypertension 140-149 〈90
What is hyperlipidemia
Hyperlipidemia occurs when one or more lipids in the plasma are higher than normal due to abnormal lipid metabolism or transport, and can manifest as hypercholesterolemia, hypertriglyceridemia, or both (mixed hyperlipidemia).
The appropriate range for total serum cholesterol in Chinese is currently considered to be <5.20 mmol/L, with 5.23-5.69 mmol/L being borderline elevated and >5.72 mmol/L being elevated. The appropriate range for triglycerides is <1.70mmol/L, >1.70mmol/L is elevated.
What is diabetes
Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia caused by various etiologies. Hyperglycemia is caused by a defect in insulin secretion or action, or both. In addition to carbohydrates, there are also abnormalities in protein and fat metabolism. Prolonged disease can lead to damage of multiple systems such as neurology, heart and kidney.
Classification of cerebrovascular disease
Approximately 80% of all cerebrovascular disease is ischemic stroke (cerebral thrombosis or cerebral embolism), with the remaining 20% classified almost equally as bleeding into brain tissue (parenchymal cerebral hemorrhage) or into the surrounding subarachnoid space (subarachnoid hemorrhage).
What is transient ischemic attack
TIA is a transient cerebral blood circulation disorder with local symptoms, characterized by transient, reversible speech, motor or sensory impairment, and disappearance of signs and symptoms within 24h. Most TIA episodes last 2-15 min, while those of longer duration often suggest the presence of an embolus. clinical analysis of TIA should also distinguish between a single transient episode and recurrent episodes, the latter often being a warning sign of the presence of vascular obstruction. approximately 20% of patients with an initial TIA develop an infarction within a month, and approximately 50% develop a cerebral infarction within a year.
Symptoms of cerebrovascular disease
When cerebrovascular disease occurs, there is damage to the brain tissue structures supplied by the affected blood vessels and corresponding functional deficits in these brain areas, which may result in changes in movement, sensation, speech, behavior and consciousness. Symptoms vary depending on the location and extent of the damage. Some of the most common symptoms of stroke are as follows.
① Sudden onset of numbness or weakness of the face or limbs (especially if it occurs on one side);
(2) Sudden onset of impaired consciousness, difficulty with speech or understanding speech;
(3) Sudden change in vision in one or both eyes;
④ sudden onset of difficulty in walking, dizziness, balance or ataxia;
⑤ Sudden onset of severe headache with no known cause.
Most of the symptoms of all strokes are of acute onset and can manifest multiple symptoms at the same time.
Imaging of cerebrovascular disease
CT is the most widely used initial test for patients with clinical suspicion of stroke.
CT can provide useful diagnostic assistance in most cases of ischemic cerebrovascular disease, whether in the acute, subacute or chronic phase. A few hours after the onset of cerebral infarction, due to early cellular changes such as those caused by cellular cerebral edema, cranial CT can have several manifestations that coincide with the early pathophysiology of acute ischemic cerebrovascular disease: loss of gray-white matter distinction, loss of cerebral sulci, high-density arterial signs, decreased insula density values, and decreased density values of the nucleus pulposus or loss of the internal capsule boundaries.
MRI manifestations of cerebral infarction vary with the progression of brain parenchyma from ischemia to necrosis and correlate with the sensitivity of the affected cells to ischemia, the degree of ischemia, and the time course of ischemia. Spin-echo sequences as well as diffusion imaging (DWI) and perfusion imaging are of great value in the diagnosis of ischemic cerebrovascular disease.
Acute cerebral hemorrhage appears as a homogeneous hyperdense shadow on non-enhanced CT, with clear boundaries but significant occupancy effects, and initially peripheral edema is not obvious. On the 3rd to 4th day of hemorrhage, hypointense changes due to peripheral edema can be observed on CT. the presentation on MRI varies with the time after hemorrhage.
Treatment options for ischemic cerebrovascular disease
As a clinical emergency, stroke requires a team of experienced neurologists, cardiologists and radiologic imaging and geriatricians to establish a stroke unit so that patients can be accurately diagnosed as early as possible and complete the ECG, blood pressure, oxygen saturation and other necessary laboratory tests, etc., and take timely and effective treatment measures, as well as special care for basic vital signs, early and rehabilitation The mortality and disability rate of stroke can often be reduced by taking timely and effective treatment measures, as well as special care of basic vital signs, early and rehabilitation training of speech and body functions.
What is thrombolytic therapy?
Most patients with ischemic stroke show early obstruction of the blood vessels, and restoration of revascularization can save tissue in the semidark zone. Thrombolytic therapy involves the use of drugs that act on fibrinolytic enzymes to convert them into active fibrinolytic enzymes, thereby causing the fibrin in the clot to disintegrate (snips up) and allowing the blood flow in the vessel blocked by the thrombus to recirculate. A key factor in thrombolytic therapy is the timing of thrombolytic therapy, i.e., the “time window”. Thrombolytic therapy within 3 hours of the onset of signs and symptoms of ischemic cerebrovascular disease has the most desirable and positive effect.
The role of aspirin in the prevention and treatment of ischemic cerebrovascular disease
The formation of emboli on the arterial surface due to platelet-fibrin has an important role in the pathogenesis of many TIAs and infarcts. Among the various treatment options for infarct prevention in patients with non-cardiogenic TIA, antiplatelet agents have the best therapeutic effect and less therapeutic risk.
Several studies have shown that aspirin application in patients with TIA or microstroke (defined as no or only very mild symptoms of neurological damage one week after the onset of ischemia) significantly reduces subsequent TIA, infarction and mortality. Small doses (50-100 mg) appear to have the same preventive effect as large doses (1000-1500 mg). The most commonly used dose in North America is 325 mg/d. A related report from the 17th Annual Scientific Sessions of the National Society of Hypertension observed that low-dose aspirin taken before bedtime reduced systolic blood pressure by an average of about 7 mmHg and diastolic blood pressure by 4.8 mmHg, whereas aspirin taken at other times had no hypotensive effect.
Management of subarachnoid hemorrhage
The patient should be kept absolutely bedridden, given fluids to maintain effective blood circulation, softened stools to bring down the elevated blood pressure and maintain the systolic blood pressure at or below 150 mmHg, and given analgesic drugs (which also have a hypotensive effect) to prevent the formation of venous thrombosis if the headache is significant. Anti-epileptic drugs may be given to prevent rebleeding that may be caused by convulsions. Subarachnoid hemorrhage is often associated with vasospasm, and calcium channel blockers are widely used to reduce the incidence of cerebral infarction due to vasospasm. Nimodipine 60 mg orally for 1/4 h is now commonly used.
The most common cause of subarachnoid hemorrhage is the rupture of an aneurysm, and arteriovenous malformations are not uncommon. Advances in microsurgery have improved the success rate of surgery, and developments in neurointerventional medicine have made endovascular treatment of aneurysms more common, especially those in areas difficult to reach surgically, such as those located in the cavernous sinus, while offering the possibility of treatment for those patients who have difficulty tolerating surgery. Repeated lumbar puncture for release and replacement of bloody cerebrospinal fluid after subarachnoid hemorrhage is no longer the usual clinical treatment. Ventricular drainage is often more effective in patients with subarachnoid hemorrhage who present with severe hydrocephalus and are more severely impaired in consciousness.
ABCDE Line of Defense
The “ABCDE line of defense” proposed by the 14th International Congress of Cardiology is of great significance for the secondary prevention of heart disease and is also applicable to the secondary prevention of cerebrovascular disease.
A-Aspirin, ACEI (aspirin, angiotensin converting enzyme inhibitors)
B-β-Blocker, Blood Pressure Control (β-blocker, blood pressure control)
C- Cholesterol Lowing, Cigarette Quitting (cholesterol lowering, smoking cessation)
D- Diabetes Control, Diet (Diabetes control, diet modification)
E- Exercise, Education (exercise, education)
Rehabilitation of cerebrovascular disease
Cerebrovascular disease can cause neurological deficits such as hemiplegia, speech impairment, cognitive and emotional impairment, pain, etc. due to the damage of the neurological structure, which affects the daily life and work of patients and increases the burden of family and society. The treatment of cerebrovascular disease is not only to reduce the mortality rate, but also to reduce the disability rate and to restore the maximum function of the patient, so it is necessary to start rehabilitation treatment as early as possible.
Rehabilitation includes a variety of treatment mechanisms, methods and tools such as physiotherapy, occupational therapy and speech training, all of which are aimed at using knowledge from biomechanics, motor learning, neuroscience and cognitive psychology to develop relearning programs for stroke patients and to promote brain reorganization and adaptability for maximum functional recovery.
Many stroke patients also rely on the help of psychologists or psychiatrists to eliminate symptoms such as depression and anxiety, which are common after stroke, and to alleviate the mental and emotional problems of patients caused by stroke.