Syncope

Introduction to syncope Syncope is a clinical syndrome, also known as fainting. This disease is caused by a sudden decrease in the whole cerebral blood flow, a temporary blood supply to the brain or insufficient oxygen supply, resulting in the inhibition of the reticular structure and loss of consciousness, which lasts for a few seconds to several minutes; the posture tension cannot be maintained during the attack, so it cannot stand. And fainted, but recovered faster. basic knowledge The proportion of illness: 0.085% Susceptible people: no special people Mode of infection: non-infectious Complications: Hypertension, Arrhythmia

Cause of syncope

Causes

Cardiac syncope

Sick sinus syndrome, atrioventricular block, paroxysmal supraventricular tachycardia, pre-excitation syndrome, ventricular tachycardia, long QT syndrome, arrhythmogenic right ventricular dysplasia, aorta Stenosis, cardiac myxoma, primary cardiomyopathy, secondary cardiomyopathy, coronary heart disease, mitral valve prolapse syndrome, viral myocarditis, infective endocarditis, pericardial disease, cardiac valve-like thrombus, Pacemaker syndrome, congenital heart disease, etc.

other factors

A. Metabolic syncope: hypoglycemia, hyperventilation syndrome, hyponatremia, etc.; B. drug-induced syncope: quinidine syncope, doxorubicin syncope, prazosin first dose syndrome, etc.; Others: upper gastrointestinal bleeding, hiatal hernia, pulmonary embolism, pregnancy-induced hypertension syndrome, cervical heart syndrome, thermal syncope, exercise syncope, etc.

Vascular disease syncope

Hypertension, arteritis, aortic dissection, primary pulmonary hypertension, cerebral arteriosclerosis, transient ischemic attack, subclavian steal syndrome.

Vascular dysregulation syncope

Angiogenesis syncope, orthostatic hypotension, carotid sinus syndrome, reflex syncope, hyperreactivity of receptors, syncope epilepsy, swallowing syncope, etc.

Pathogenesis

The most basic cause of syncope is the lack of temporary cerebral blood supply, so understanding some of the problems related to cerebral blood flow is beneficial for further understanding of syncope.

Adult brain weighs about 1500 grams, accounting for 2% to 2.5% of body weight, while brain blood flow accounts for 15% of systemic blood flow, brain oxygen consumption accounts for 20% of total systemic oxygen consumption, and children up to 40%, normal. The blood flow per 100g brain tissue per adult is 40-50ml. If it is reduced to 31.5ml, the symptoms of cerebral ischemia will occur. Therefore, it is necessary to ensure normal cerebral blood flow. The blood volume of the normal person must flow through the brain within 24 hours. About 1700L, the oxygen consumption is about 72L. The cerebral blood flow is closely related to the effective perfusion pressure and cerebrovascular resistance. It is also related to intracranial pressure, blood viscosity and blood vessel diameter.

The cerebral blood flow varies with age, and the state of the body changes. For example, when thinking, high fever, and anxiety, the cerebral blood flow increases, and when the body temperature decreases, the cerebral blood flow also decreases, but the fluctuation range of the cerebral blood flow is Limited, its cerebral blood flow automatic regulation function is the guarantee that the necessary blood flow can be obtained when the brain tissue is normal. Under normal circumstances, due to the automatic regulation of cerebral blood vessels, the change of systemic blood pressure does not affect the cerebral blood flow, when the blood pressure rises. Causes increased cerebral vascular resistance, decreased blood cerebrovascular resistance when blood pressure drops, keeps cerebral blood flow constant, and cerebrovascular autoregulation function plays a role in large blood pressure fluctuations when average arterial blood pressure is lower than 8 to 10.8 kPa (60) 80mmHg), this protective cerebral blood flow autoregulation function is lost, and some people in the experiment block -adrenergic receptors to lower the lower blood pressure limit to 4.7kPa, so it is considered that the automatic regulation of cerebral blood flow It is achieved by innervation, but there are other factors that can affect cerebral blood flow, such as carbon dioxide and oxygen concentration in arterial blood, blood viscosity, Pipe diameter, etc., if cerebral blood flow is stopped 6 ~ 7min, lower than 2.7kPa partial pressure of oxygen within blood, brain cells because they can not normal oxygen metabolism, it can be severe brain dysfunction.

Regarding the pathophysiology of syncope, it is believed that cerebral ischemia first affects the cerebral cortex and basal ganglia, which are highly sensitive to hypoxic conditions, followed by the hypothalamus and midbrain, while the medullary pons reticular structure has an abnormal state of hypoxia. Large tolerance, according to some people, the first stage of syncope episodes, slow waves appear in the EEG, indicating hypoxic damage in the hypothalamic-cortical level of the brain, clinically manifested as loss of consciousness, muscle When the tension is reduced and a fall occurs, when the cerebral hypoxia state continues to exist and the pons is endangered, the medullary life center, the safety feedback mechanism for stopping the cerebral hypoxia plays a role, causing the cardiac inhibition reflex and the blood vessel reflex reflex to function, resulting in a normal heart rhythm. And maintaining an effective circulation of the vascular tone, causing the syncope to terminate.

Syncope prevention

If you feel that syncope is about to happen, assuming that the cause is a temporary drop in blood pressure, there are two simple ways to avoid loss of consciousness. The first method is to cross the legs, compress the abdominal muscles, and squeeze the veins of the legs (the veins in the legs) Blood flows to the heart) and stimulates the nervous system to contract the artery (increased blood pressure) to increase blood pressure. The second method is to grasp the other hand with one hand and then straighten the arms.

Drinking two glasses of water, although not effective immediately, may prevent syncope within 30 to 60 minutes. The reason may be to supplement the blood volume. Similar suggestions are to sit down and bury your head between your legs. This will make you feel better. Sit down to avoid syncope and bury your head between your legs to get more blood from your brain.

If syncope has occurred, it is best to let the patient lie flat on the ground, so that the cardiovascular system does not have to fight gravity, and the patient's body is turned to one side to avoid aspiration. It is wrong to make people sit after fainting, because blood can't be used. Do not flow up to the brain.

Syncope complications Complications, hypertension, arrhythmia

A small number of responders can cause unnecessary damage after fainting falls, and may cause aggravation of chronic diseases in older people, and complications are life-threatening.

Symptoms of syncope Common symptoms Simple syncope Exogenous vertigo occurs during urination and fainting of the pharyngeal neuralgia or it... Situational syncope, dizziness, tinnitus, blood pressure, drop, holiday heart syndrome, vertigo

Main performance

A typical syncope episode can be divided into three phases.

(1) Predecessor period:

Symptoms of autonomic nerves are obvious, suddenly pale, cold sweat, nausea, upper abdominal discomfort, enlarged pupils, fatigue, dizziness, tinnitus, yawning and blurred vision, etc., due to decreased muscle tone and body swing, this period lasts a few seconds, so When the patient immediately sits down or lie down, the symptoms gradually subsided, otherwise the consciousness is quickly lost and the next phase is entered.

(2) Syncope period:

Loss of consciousness and loss of muscle tension disappeared, the patient's pulse is fine, blood pressure is often lowered, breathing is shallow, pupil dilated and light reflex disappears, tendon reflex disappears, limbs are cold, and urinary incontinence may occur. In a few minutes, the consciousness gradually recovers and enters the next stage. If the loss of consciousness lasts for several tens of seconds, small facial and limb myoclonic tics can occur.

(3) Recovery period:

The patient gradually wakes up, still pale, sweating, weak body, can have nausea, hyperventilation, but unconscious confusion and headache, rest for ten minutes to fully recover, such as just waking up quickly, can faint again, After the onset, there will be no sequelae of nerves and body.

Some episodes may have no predisposing discomfort. When a disease occurs, the consciousness is lost and falls, which is easy to cause trauma.

In the prodromal EEG, the brain wave frequency is slowed down and the amplitude is increased; the syncope period is generally 2 to 3 Hz slow activity; the brain wave gradually changes to normal during the recovery period.

2. Clinical type

The clinical classification of domestic Lu Liang's classification is relatively simple. It is introduced as follows:

(1) Hypotension syncope: Hypotension can be caused by reflex arc dysfunction that regulates blood pressure and heart rate, or due to autonomic nervous system or dysfunction, which is only one symptom of the disease.

1 Reflective syncope:

In recent years, it has also been called neural mediated syncope, including several types with roughly the same pathogenesis.

A. vasodepressor syncope: also known as vasovagal syncope (vasovagal syncope) or simple syncope, is the most common type of clinical, men and women of any age can be affected, 20% of young people ~ 25% suffer from this disease, more common in younger women, and there are obvious causes of the disease. Commonly, it is pain, fear, seeing bleeding, receiving injection or minor surgery, sultry weather, crowded places, hunger, fatigue, etc. Most of the onset occurs when standing, occasionally when sitting, and the lying position will never occur.

The clinical manifestations were typical of 3 phases. The systolic blood pressure decreased to 7.98 kPa (60 mmHg) or below when syncope, and the pulse slowed to 40-50 times/min. Most patients had only occasional seizures. A few patients had a family history and blood pressure was normal. Range or normal low level.

B. micturition syncope: The patient is almost all male, the middle-aged patient is the most, fainting occurs during standing urination or just after urinating, often at night, in the morning or nap to get up when urinating, more prodromal symptoms Sudden syncope, milder symptoms during recovery, cold after drinking, fatigue is a possible cause, in addition to the reflex arc dysfunction mainly due to blood pressure and heart rate adjustment, but also increased intrathoracic pressure during urination, and get up after lying for a long time. Insufficient blood supply to the brain, as well as high vagal nerve tension at night, and low blood pressure, etc., some people attribute it to multi-factor syncope, and deficient scan syncope is rare, and its mechanism is similar to urinary syncope. .

C. tussive syncope: immediate loss of consciousness after severe cough, low muscle tone, short-term transit, a small number of patients first feel dizzy, vertigo, complexion changed from bruising to pale, sweating, patients mostly after middle age Obese men, who often smoke and have bronchitis and emphysema, children who have pertussis or asthma also have the disease, most after repeated cough, occasionally seen in a single cough, call, sneeze, yawn or laugh immediately after fainting Cough causes the intrathoracic pressure to increase, causing venous return obstruction and cardiovascular reflex factors to play a role in the disease.

D. swallowing syncope: seen in the throat, esophagus, esophagus, mediastinal disease and / or atrioventricular block, sick sinus syndrome, bradycardia, myocardial infarction patients, swallowing cold, hard Short-term syncope after acid, spicy food or gas-producing beverages, no obvious discomfort before and after the attack, but also independent of body position, pathogenesis and mechanical stimulation of the upper digestive tract, abnormal afferent impulses trigger cardiovascular reflex inhibition, and cardiac conduction The system is sensitive to gynecological excitement.

E. Syncope caused by glossopharyngeal neuralgia or other visceral diseases: this type of syncope is rare, glossopharyngeal neuralgia, biliary colic, renal stenosis, transient fainting during bronchial or digestive tract endoscopy, severe pain and visceral receptors The over-reflective response is related.

F. Carotid sinus syncope (also known as hypersensitive carotid sinus), is a common cause of syncope in men over middle age, patients often have carotid atherosclerosis, or carotid body tumor, Inflammation of the carotid sinus, or compression by adjacent tumors or enlarged lymph nodes, mediastinal tumors, etc., in the case of over-conversion of the neck, bowing, looking up, or the collar is high and tight and so on.

When syncope, the patient is often in an upright position, the loss of consciousness is shorter, and the symptoms are not obvious after the prodromal and post-onset.

When the syncope is not obvious, the blood pressure is not obvious, and there is sinus bradycardia or atrioventricular block. The sinus arrest is called vagus type, which is more common.

When the syncope is significantly reduced in blood pressure and the heart rate changes are not obvious, it is called decompression type.

Blood pressure and heart rate are significantly reduced, said mixed type.

Blood pressure and heart rate do not change much, but those caused by extensive brain blood supply are called brain type.

It should be noted that there is a certain risk in the diagnosis of carotid sinus massage. It should be carried out under the monitoring of electrocardiogram. The massage time should not exceed 20s, the blood pressure of normal people should not exceed 1.33kPa (10mmHg), and the heart rate should not slow down more than 5 times/min. If the blood pressure drops more than 2.66 kPa (20 mmHg), the heart rate slows down more than 20 times/min, which is carotid sinus allergy. If the syncope is induced, the diagnosis can be confirmed.

In addition, when a carotid artery or a vertebral artery is partially occluded, compression or massage of the contralateral carotid artery can also cause syncope, and non-neck sinus allergy or cerebral blood supply is insufficient. Bruni (1995) pointed out that although over 60 years old 10% of the population has carotid sinus allergy, but not all of them will have syncope.

Reflex syncope is an abnormality of autonomic nerve reflex activity that regulates blood pressure and heart rhythm in the body, resulting in lower blood pressure and slower heart rate, causing a sudden decrease in global cerebral blood flow. In the process of syncope, parasympathetic activity is significantly increased, and acetylcholine is released. The latter is a powerful stimulant for the synthesis of carbon monoxide (NO) in vascular endothelial cells, and the increase of NO leads to vasodilation. The monophosphate ring guanine (cGMP) in urine can be used as a biomarker for NO activity. In the passive upright positional slab test, the cGMP was reduced by 67% in normal human heads and 220% in syncope patients.

2 erect hypotension syncope:

It refers to the syncope that occurs when the patient changes from a lying position or a long time to a vertical position when the blood pressure drops significantly. When a normal person suddenly stands in a lying position or a long time, a large amount of blood (300-800 ml) is quickly transferred to the lower limbs, causing blood flow to the heart. A sudden decrease in blood pressure, but a decrease in blood pressure, but a signal through the carotid sinus and aortic arch baroreceptor, which reduces the inhibition of the vasomotor center and increases the sympathetic-adrenergic system tension, with the involvement of the renin-angiotensin-aldosterone system. The arteries are contracted and the heart rate is accelerated, and sufficient cardiac output is maintained, and the blood supply to the brain is not affected.

The autonomic nervous system plays a key role in this compensatory regulation through the sympathetic efferent pathway. Therefore, the sympathetic function caused by autonomic nervous system disorders or lesions leads to uprightness (posturality). Hypotension, this type of orthostatic hypotension is neurogenic.

Non-neurogenic orthostatic hypotension, most often caused by a decrease in cardiac output due to hypovolemia, absolute hypovolemia seen in massive bleeding, dehydration, loss of body fluids (vomiting, jejunostomy), burns, dialysis, diuresis, adrenal gland Cortical insufficiency, diabetes insipidus, etc.; relatively low blood volume is seen in severe lower extremity varices, hyperbradykinism, high extremity veins and capillaries are highly dilated, vasodilators are used, and other heart damage Myocardial disease, atrial myxoma, constrictive pericarditis, aortic stenosis, etc., also have orthostatic hypotension. When autonomic dysfunction, mild dehydration (diarrhea) or vasodilators are more likely to cause low Blood pressure and syncope.

Neurogenic orthostatic hypotension includes both primary (special) and secondary.

Primary autonomic dysfunction is mainly Shy-Drager syndrome. In addition to orthostatic hypotension, this syndrome also has other autonomic and central nervous damage symptoms; pure autonomous failure is rare. Only low blood pressure and no other signs of nerve damage.

There are many causes of secondary autonomic dysfunction, including central ventricle or posterior fossa tumor, high spinal cord disease, medullary cavity, multiple sclerosis, etc.; peripheral multiple neuropathy, diabetes, amyloidosis, sympathetic Neurotomy, dopamine -hydroxylase deficiency, familial autonomic dysfunction (Riley-Day syndrome), Holms-Adie syndrome, etc.; other causes are autoimmune and collagen diseases, renal failure, AIDS, And acts on sympathetic-adrenergic system drugs such as clopidogrel, methyldopa, reserpine, guanethidine, propranolol and barbital.

The characteristics of orthostatic hypotension and syncope are no obvious incentives. They faint when standing in a lying position or a long position. The symptoms in the prodromal and recovery periods are not obvious, the time of loss of consciousness is short, the blood pressure drops significantly, and the heart rate is slow. (Subsequent to low blood volume may have tachycardia), the symptoms of mild people only feel dizzy when standing up, black or vertigo in front of the eyes but unconsciously lost, such patients in the upright position, blood pressure is significantly reduced, but not necessarily They are fainting.

Physiological erect hypotension is seen in young people standing for a long time, especially when the weather is hot. It is also seen when the long-term bedridden suddenly stands up. The reason may be that the muscles and veins of the lower limbs are low, the blood is deposited in the lower limbs, and the blood volume is reduced. Temporary lack of blood supply to the whole brain.

(2) cardiogenic syncope: a variety of heart disease can occur syncope, syncope can be induced by force, most have nothing to do with body position, conscious heart loss before convulsions, chest pulsation or chest pain, rapid onset, usually short-term, The symptoms of the prodromal and recovery period are not obvious.

1 arrhythmia: complete atrioventricular block, especially the emergence of A-S syndrome, sick sinus syndrome, ventricular or supraventricular paroxysmal tachycardia, atrial fibrillation, and the use of drugs Such as quinidine, digitalis, bismuth potassium tartrate, etc.; can occur bradycardia (less than 35 ~ 40 times / min), tachycardia (higher than 150 times / min), cardiac output per stroke or Interruption, resulting in global cerebral ischemia and syncope.

The typical clinical manifestation is A-S syndrome, which is more common in middle-aged patients. When the heart stops for 5-10s, it can cause syncope, pale, pulse and heart sound disappear. If the attack time is long, it is difficult to breathe, cyanosis, visible. The clonic muscle convulsions like epileptic seizures can be consciously blurred afterwards, and transient positive signs are easily misdiagnosed as epileptic seizures.

Long QT syndrome (long QT syndrome) combined with congenital deafness, also known as surdo-cardiac syndrome, is an autosomal recessive hereditary disease with a family history of sudden cardiac death, which can occur 10 years after birth. Mostly women; exercise, fear, loud noise can induce ventricular fibrillation and syncope, acquired long QT syndrome can appear in adults like epilepsy, the causes include cardiac ischemia, mitral valve prolapse, myocarditis, drugs and Electrolyte disturbances, etc.

2 coronary heart disease and myocardial infarction: coronary heart disease can be caused by acute myocardial ischemia caused by ventricular arrhythmia, myocardial infarction, especially left ventricular anterior wall infarction, prone to syncope, mainly due to left ventricular anterior wall inner plexus and carotid artery The sinus is related, and with the participation of reflective factors, the patients are mostly elderly hypertensive or coronary heart disease patients, some have syncope and arrhythmia first, then there is pain in the precordial area; others have angina before, then syncope occurs. The syncope caused by myocardial infarction lasts for a long time. After waking up, there may be nausea, vomiting, and general weakness.

3 heart disease caused by decreased cardiac output: in addition to coronary heart disease and myocardial infarction, congenital heart disease, especially tetralogy of Fallot; acquired aortic stenosis, pulmonary hypertension, valvular heart disease and arrhythmia or cardiac function Incomplete, left atrial myxoma or giant thrombus, constrictive pericarditis, pericardial effusion, upper and inferior vena cava occlusion, and tension pneumothorax; all cause a decrease in cardiac output, global cerebral ischemia and syncope.

This type of syncope is characterized by prone to syncope when exerted, short-term, short-term, prodromal and recovery symptoms are not obvious, left atrial myxoma patients are mostly adult women, when the body position changes the tumor is embedded in the open mitral valve orifice, Blocking the left ventricular inflow tract, the left ventricular discharge is suddenly reduced, causing syncope, left atrial giant thrombus or left heart prosthetic valve dysfunction, also caused by the same mechanism of syncope.

(3) Cerebrovascular syncope:

Syncope is occasionally observed as a consequence of reduced blood flow in the carotid or vertebral arterial system. The most common cause is atherosclerosis of the cerebral arteries, followed by neck disorders such as cervical vertebrae joint compression of the vertebral artery, multiple arteritis ( No pulse disease), subclavian artery stealing blood syndrome, basilar artery type migraine, subarachnoid hemorrhage.

A transient ischemic attack of the carotid or vertebral artery, with focal symptoms in the vascular supply area, occasionally with syncope, and all symptoms resolved within 24 hours.

2 1/3 to 2/3 of patients with multiple arteritis have syncope, which occurs during activity, and the pulsation of each large blood vessel is a feature of this disease.

3 In the subclavian steal syndrome, loss of consciousness was induced by upper limb activity, and the pulsation of the affected side was weakened or disappeared. The blood pressure was 2.66 kPa (20 mmHg) lower than the contralateral side.

4 Basilar arterial migraine is more common in young women, often with a positive family history, first dizziness, headache later, more syncope occurs before the headache, loss of consciousness gradually occurs, and there are hours of confusion, cerebral vasospasm is considered The cause of syncope.

(4) multi-factor syncope and other syncope: Some of the pathogenesis of syncope mentioned above, some involve more than one factor, such as urinary and coughing syncope, the mechanical factors and reflections of venous return caused by increased intrathoracic pressure Sexual factors work together; left ventricular anterior wall myocardial infarction is related to carotid sinus reflex; classification should be based on the main factors.

Other syncopes are as follows:

1 hyperventilation causes syncope: mostly hysteric, after stimulation, respiratory enhancement and hyperventilation increase carbon dioxide emissions and produce respiratory alkalosis, causing cerebral ischemia caused by contraction of capillary capillaries, alkalosis Free calcium in the blood, these changes cause dizziness, dizziness, dry mouth, facial and limb numbness, hand and foot spasm, chest tightness, panic, gradually loss of consciousness, rapid heartbeat, but normal blood pressure, comfort and suggestion can be effective Slow intravenous injection of 10 ml of calcium gluconate can relieve hand and foot spasm.

2 crying fainting: also known as breath-holding spells (breath-holding spells), commonly known as "gas death", seen in children aged 1 to 4 years, often due to pain, being scolded or scared and sick, the child crying with a cry Breathing, face bruising, loss of consciousness, wake up after a few seconds or ten seconds to recover from breathing, easily misdiagnosed as epilepsy, no longer after 3 to 4 years old.

3 supine hypotension syndrome: seen in the late pregnancy and a large tumor in the abdominal cavity, the patient took the supine position, the blood pressure plummeted, the heart rate increased, dizziness and even syncope, because the enlarged uterus or tumor pressed the inferior vena cava, Caused by a sudden drop in blood volume, the symptoms can be alleviated when the position is changed to the sitting position or the right lateral position.

Syncope check

The physical examination of patients with syncope focuses on the cardiovascular system, paying attention to changes in blood pressure in the supine and upright positions, differences in blood pressure on both sides, major arterial pulse, heart rate, heart rate, and heart murmur.

Fecal occult blood test can help to understand whether there is gastrointestinal bleeding, and it is meaningful to identify the cause of orthostatic syncope. Blood routine examination may be helpful for patients with bleeding, hypoglycemia, hyponatremia, hypocalcemia or renal function. Depletion can be seen in a small number of patients with syncope, autonomic nerve function test sometimes helps to detect the neuropathy of orthostatic hypotension, such as serum catecholamine and dopamine- hydroxylase levels in the supine and upright positions, if there is no change, it suggests that special hair Sexual hypotension or autonomic neuropathy.

Electrocardiogram is important for diagnosing arrhythmia and myocardial ischemia; echocardiography can detect various cardiac structural abnormalities.

There are three main types of special tests that contribute to qualitative diagnosis:

Carotid sinus massage test

The patient was placed in the supine position. Under the monitoring of electrocardiogram and EEG, the left and right carotid sinus were massaged with the thumb for 20s respectively. Those who had no allergic reaction were massaged for two times at the same time, first lightly, then gradually pressurized, normal. The heart rate is reduced by no more than 5 times/min, and the blood pressure drops no more than 1.33 kPa (10 mmHg). The carotid sinus allergy has abnormal reaction after 10 s of massage, including slow wave of EEG, heart rate is obviously slow, pale, and syncope Even convulsions, once the abnormal reaction, immediately stop the massage, this test has a certain risk, physical weakness, cardiovascular disease or cerebrovascular disease is listed as a taboo, for the suspected carotid sinus syncope can be used for this test Determine the diagnosis.

2. Lying-standing blood pressure measurement

The subject was placed supine, the blood pressure was 2 min, the erect position was followed, the blood pressure was immediately measured, and the test was repeated once in 3 min. The subject rested for 5 min, and then the above-mentioned lying-up measurement was performed once, and the normal person was in the upright position. The systolic blood pressure drops not more than 2.66 kPa (20 mmHg), the diastolic pressure does not change, the systolic blood pressure drops more than 2.66 kPa (20 mmHg) when standing upright, the diastolic blood pressure drops over 1.33 kPa (10 mmHg), and the symptoms of syncope prolapse or syncope appear to be diagnosed as Orthostatic hypotension.

3. Inclined bench test

Also known as the passive fascia test, it has a specific diagnostic value for neuromodulation syncope. The patient is lying supine on a pedal-mounted electric platform, and the chest and knee are fixed with a wide band so that the lower limb is raised when the fascia is erected. Do not support the body to prevent the pumping effect of muscle contraction, install the ECG and blood pressure monitor, set the seesaw to the head of the 60-foot angle, high and low, lasting 40 minutes, only about 5% of normal people have syncope, have syncope 41% of the historians induced syncope, often after 10 minutes, blood pressure decreased significantly, heart rate decreased significantly, pale, loss of consciousness, once the syncope appeared, immediately return the tarsal plate to the level, consciousness, blood pressure and heart rate will soon return to The original level, for the absence of organic heart disease, and unexplained syncope can be used for this test.

Syncope diagnosis

diagnosis

Diagnosis can be based on symptoms.

Differential diagnosis

Syncope needs to be distinguished from dizziness, dizziness, collapse, epilepsy, shock, and coma.

Dizziness

It means that the mind is dim, often accompanied by dazzling, the feeling of shaking the body, there is no disturbance of consciousness.

2. vertigo (vertigo)

It is a subjective experience error of the patient's alignment (space-oriented sensation). The patient consciously rotates or moves to one side, or feels that he is rotating, shaking or rising and falling. The patient is often described as "spinning" and "unsteady footsteps". "If you take a boat," "slanted to one side" and so on, but the consciousness is clear, mostly the performance of vestibular neuropathy.

According to its clinical manifestations, it can be divided into two types: peripheral vertigo and central vertigo. Peripheral vertigo is often Meniere's disease, middle ear infection, mastoid and labyrinth infection, labyrinthitis, vestibular neuritis, acute vestibular nerve injury. , caused by obstruction of the eustachian tube; often manifested as paroxysmal vertigo, accompanied by tinnitus, deafness and nausea, vomiting, pale, slow heartbeat, cold sweat, etc., central vertigo is often increased intracranial pressure, insufficient blood supply to the brain, cranial Brain trauma, cerebellum, fourth ventricle and brain stem occupying lesions, acoustic neuroma, epilepsy, etc.; mostly progressive, dizziness is persistent, with or without autonomic symptoms.

3. Seizure (seizure)

It is caused by abnormal discharge caused by the excitability of nerve cells in the brain. At the time of seizure, the regional cerebral blood flow and the oxygen metabolism rate of the brain are not reduced, but greatly increased. Therefore, the essence of syncope is completely different, although Patients have different clinical manifestations due to the location of the discharge, the mode of transmission and the extent of the lesion, but often accompanied by loss of consciousness, and have three characteristics of suddenness, temporary and repetitive, which should be distinguished from syncope, for suspicious patients, Patients should be informed about the onset of the patient and their family members or those who are on the side of the patient's episode, and a detailed physical examination should be performed to determine whether it is epilepsy. Epileptic seizures are often accompanied by persistent systemic muscle contractions and characteristic features are determined. Diagnosis is not difficult. For epileptic seizures, it usually shows a transient loss of consciousness lasting about 5~10s, and there is no obvious muscle contraction and convulsion. When the attack occurs, the patient suddenly stops the work or movement that is going on, and is in a dull state. No response to the outside world, or direct attention, the hand falls, the patient can continue the original work after the attack Action or interrupted speech.

Epileptic seizures are easily confused with syncope. The difference between the two is that the seizure and disappearance of the former are more rapid and sudden than the latter. After the episode, the original work or movement can be continued without any obvious autonomic dysfunction. The performance of EEG often has abnormal changes (synchronized with bilateral symmetry of 3 weeks / s spine - slow wave), and when syncope occurs, there are often different degrees of prodromal symptoms, there are more obvious autonomic nerves after the attack Symptoms or other primary disease manifestations, EEG only appear slow waves at the time of onset.

Another type of epilepsy that needs to be distinguished is malignant cerebral epilepsy, which is a clinical syndrome caused by hypothalamic lesions. The cause is mostly infection, trauma or degeneration. The episode is characterized by inter-brain symptoms, mainly manifested in autonomy. Neurological disorders, but no loss of consciousness.

4. collapse

It refers to a state of extreme fatigue and weakness caused by a large loss of body fluids, heart disease, cholera, typhoid, pneumonia, etc., caused by various causes of transient peripheral circulatory failure, but not accompanied by loss of consciousness. It manifests as skin, pale or mild cyanosis, rapid drop in blood pressure [systolic pressure 8.0 kPa (60 mmHg)], weak pulse, sweating, etc.

5. Shock (shock)

The original meaning is shock and blow, also from Greek, which first refers to the pathological process that occurs when the body is subjected to severe shocks and blows, that is, traumatic shock. It refers to acute circulatory disorders caused by various causes such as infection, blood loss or fluid loss, and trauma. The systemic pathological process of severely impaired tissue blood perfusion, resulting in the vital function of various vital organs.

Typical clinical manifestations include lower blood pressure, faster heart rate, weaker pulse, pale skin, dampness on the forehead and limbs, decreased urine output, wilting, apathy, and in the process of development, if the patient is not effectively rescued and treated, the whole body is organized and The organ will undergo irreversible damage and cause death.

The fundamental difference between it and syncope is that the key to shock pathology is not blood pressure but blood flow. The basic link of the disease is the drastic reduction of the vital irrigation vessels (including capillaries and post-capillary venules). Therefore, the treatment The key is not simply to raise blood pressure, but to improve blood flow in the microcirculation.

6. Coma (coma)

It is a state of deep unconsciousness caused by various diseases such as diabetes, uremia or intracranial lesions. It is a persistent loss of consciousness and is a serious stage of disturbance of consciousness. The brain can only be caused by considerable inhibition or damage. coma.

The main difference between syncope and coma is the duration of loss of consciousness. The coma is caused by intracranial space-occupying lesions, hemorrhage, tumor or infection, and metabolic disorders of the brain such as severe hypoglycemia and liver failure. Insufficient blood supply to the brain causes less coma, so the pathogenesis is different.

The medical history and physical examination are the most important in the diagnosis of syncope. The doctor should know the details of the syncope episode from the patient and the target author, including whether there is any incentive, the history of taking vasoactive drugs, the position at the time of onset, the presence or absence of prodromal symptoms, and the gradual onset. Or suddenly fainted, face color, pulse and blood pressure, convulsions, urinary incontinence, duration of loss of consciousness, unconscious confusion and headache after waking, discomfort during recovery, with or without sequelae.

There are significant differences in the age and gender of onset of different types of syncope. Children and young adults are often caused by vascular decompression or hyperventilation. A few are congenital heart disease or rheumatic heart disease; syncope of basilar artery type migraine is most common in Young women; urinary syncope is seen in middle-aged men; those who develop syncope in their later years are most common in organic heart and cerebrovascular diseases.

Vascular decompression syncope and erect hypotension syncope, the patient is in standing or in the supine position, the disease occurs after standing for a long time, and there are many prodromal symptoms. After the force, the syncope should be considered to be cardiogenic, and there is a heart and chest before the syncope. The internal fluttering sensation, the rapid onset, has nothing to do with the body position, and the menstrual syncope is often accompanied by focal neurological signs.

The first dose of syncope after taking the drug can be seen in the administration of prazosin, captopril or nitroglycerin. Some vasoactive drugs can cause orthostatic syncope, antiarrhythmic drugs, phenothiazines or tricyclic antibiotics. Depressive drugs can stimulate tachycardia arrhythmias, methyldopa, beta blockers or digoxin, and can also aggravate carotid sinus allergy.

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