Common causes of syncope in childrenSyncope is a transient loss of consciousness caused by transient cerebral insufficiency, often accompani
Common causes of syncope in children
Syncope is a transient loss of consciousness caused by transient cerebral insufficiency, often accompanied by a decrease in muscle tone and a lack of maintenance. Syncope is a common clinical disease of children, the reasons are complicated, including nerve mediated syncope (reflex), cerebrovascular disease syncope, psychogenic syncope, cardiac syncope, metabolic syncope, unexplained syncope; nerve mediated syncope is a common disease, and vasovagal syncope this is the most common type of syncope syncope; although the incidence rate is low, but the abrupt onset and dangerous, and should pay attention to. There are many causes of syncope
The understanding of disease directly affects the prognosis and prognosis of children.
Syncope is one of the most common clinical symptoms, syncope occurred in older children and adolescents, Guzman-Perry survey of male college students in 15.5% had syncope, Collins reported in the U.S. Air Force has had a history of 22.3%. The infant's breath attack (Breath-holding) and fainting similar Menkes estimates in May 5% ~6 year old children had a history of syncope like breath attack, high incidence of these infants older. The incidence rate of female was higher than that of male (2:1), and there were 2 peak age groups in the incidence of syncope, which were 15-19 and  respectively. The cause of syncope complicated nerve mediated syncope (reflex) is the most common cause, and vasovagal syncope (Vasovagal syncope VVS) is the most common type of syncope, the data show that the nerve mediated syncope (60%-71%) the most common, followed by cerebrovascular syncope and spirit (11%-19%), cardiogenic syncope (6%).
Syncope is generally not life-threatening, but recurrent syncope will seriously affect the health and quality of life of children, causing extreme anxiety of family members, and easily lead to unintentional injuries among adolescents, and therefore much attention; at the same time, many of their primary disease syncope, has great influence on the prognosis and outcome of patients.
neurally mediated syncope
Also known as reflex syncope is the most common type of clinical syncope, including vasovagal syncope, carotid sinus syndrome, pain syncope syncope, situational relevance, visible in all ages, common characteristics of these types of syncope is caused by vascular tension and heart rate changes happen suddenly nervous reflex mediated the guide, the mechanism is not entirely clear, some patients may be due to receptor or ventricular wall of bladder, esophageal, respiratory tract, and other organs of the carotid sinus reflex activation, increased vagal activity and decreased sympathetic activity.
1 vasovagal syncope (Vasovagal syncope, VVS)
Is the most common cause of syncope in children, accounting for 80% of all children with unexplained syncope. The autonomic nervous system plays an important role in the pathogenesis of VVS, and the polymorphism of the gene may lead to the change of the function of the adrenergic receptor and the disorder of the autonomic nervous system.
VVS can be set from the attack, which is in a period of time frequently, after a period of time to reduce or stop, 11-19 year old girl good hair, usually induced by persistent standing or see bloodshed, feel pain, in a hot environment, hot bath, exercise or stress. Before the onset may have premonitory symptoms: transient dizziness, inattention, pale, visual decline, nausea and vomiting, sweating, standing instability, syncope mainly for fall, loss of blood pressure, heart rate decreased, weak pulse, pale, consciousness, some patients had mild incontinence, convulsions, symptoms general for a few seconds to 2 minutes, wake up after systemic weakness, dizziness, thirst, also can be secondary to fulminant diarrhea and vomiting.
2 postural tachycardia syndrome
Most of the children were school-age children, and the incidence rate of girls was higher than boys. The children has the following symptoms: the erect syncope appears to dizziness or vertigo, headache, palpitation, chest tightness, complexion change, blurred vision, fatigue, morning discomfort, serious, these symptoms were relieved or disappeared in children after supine; although it often occurs in the standing position, but can also occur in the sitting position when.
3 orthostatic hypotension
Because of a squatting or lying in, suddenly changes to a sitting or standing position, and decrease blood pressure. The occurrence of this disease may be related to autonomic dysfunction. Simple orthostatic hypotension, more common in young people, accompanied by dizziness, palpitations, shortness of breath, pale, cold sweats, nausea and unstable; secondary orthostatic hypotension, in diseases of the nervous system, hematopoietic system disease, malnutrition, or drug allergy.
Nerve mediated syncope mainly depends on the vertical test or tilt test (head-up tilt test, HUT), orthostatic test has the advantages of simple operation, less dangerous, children's Hospital Affiliated to Shanghai Jiao Tong University Department of Cardiology to carry out HUT (tilt angle of 80 degrees, the test duration, 30min) on syncope group 74 cases and 54 cases in normal control group prospective study of HUT diagnosis of vasovagal syncope has a higher sensitivity (55.4%) and specificity (100%) .
4 situational syncope
Refers to the occurrence of syncope in a certain situation.
(1) micturition syncope: common in male patients with urination, urination, or urination, especially when they are lying in bed. The reason is unclear, due to the sudden release of pressure in the bladder, causing vasodilation and reduced venous return, Valsalva and urination, which reduced cardiac output, vagus reflex mediated bradycardia is a precipitating factor.
(2) defecation syncope: syncope or syncope during defecation is called syncope. It is suggested that there are potential digestive diseases, cardiovascular diseases or cerebrovascular diseases. It can occur in children, and can occur repeatedly.
(3): cough syncope often occurs in a cough, the children suddenly appeared weak and feeble and short loss of consciousness. The mechanism may cause syncope has three: one is due to paroxysmal cough pleural pressure increased, the effect of venous return, the cardiac output decreased, blood pressure decreased; the second is due to the increased intracranial pressure in pleural cavity to enable increased intracranial pressure; the third is due to cough blood CO2 tension decreased, increased cerebral vascular resistance, brain decreased blood flow to cause syncope.
(4) swallowing syncope: the main manifestations of children with swallowing or swallowing hot or too cold food or even when the food appears syncope or syncope aura. Generally associated with esophageal and pharyngeal injury or glossopharyngeal nerve paralysis.
(5) carotid sinus syndrome in children is rare, syncope occurred mainly due to compression of the carotid sinus mild reaction is too strong, causing the vagus nerve hyperexcitability, resulting in sinus bradycardia, sinus arrest or atrioventricular block caused syncope. These patients with syncope often in the head to the side of the rotation or tight collar, such as enlarged lymph nodes, tumor, surgical scar forced isobaric carotid sinus near or carotid sinus lesions. There are no symptoms of nausea, pallor, and so on. The loss of consciousness is not more than a few minutes. Carotid sinus massage is an important method for the diagnosis of carotid sinus hypersensitivity.
(6): the autonomic nerve dysfunction of autonomic nerve dysfunction include primary autonomic failure and multiple system atrophy of primary disease and secondary autonomic failure, such as secondary to Parkinson syndrome (parsons'disease) or diabetes. The pathogenesis of the disease is mainly due to the autonomic nervous system regulation, the blood volume is decreased, and the blood is mainly accumulated in the lower limbs when standing, so that the children's blood pressure drops, dizziness, severe and even fainting.
Cardiogenic syncope is caused by the pathological mechanism of the rapid or slow fatal arrhythmia and heart function disorder and other mechanical flash, cardiac output decreased sharply, caused by acute cerebral ischemia. Compared with other types of syncope, the incidence is lower in children, but it is more urgent and dangerous.