(2) Postural tachycardia syndrome (POTS): In recent years, the concept of POTS was put forward in children, which is one of the manifestations of chronic orthostatic intolerance and can even lead to syncope in severe cases. According to our research, POTS also accounts for a large proportion of children with unexplained syncope. According to our observation, its clinical feature is that POTS children are mostly school-age children, and the incidence rate of females is higher than that of males. Children have the following symptoms when standing upright, such as dizziness or dizziness, chest tightness, headache, palpitation, complexion change, blurred vision, fatigue, discomfort in the morning, and severe syncope. These symptoms are relieved or disappeared after lying flat; Although these symptoms often occur in the standing position, they may also occur in the sitting position. The diagnostic criteria of POTS are that the heart rate increases by ≥30 beats/min or the maximum heart rate is ≥ 65,438+020 beats/min after HUT test or upright position, accompanied by symptoms of intolerance in upright position, which can diagnose other basic diseases that can lead to symptoms of autonomic nervous system, such as anemia, arrhythmia, hypertension, endocrine diseases and other cardiogenic or neurogenic diseases that lead to syncope.
(3) Orthostatic hypotension (OH): Orthostatic hypotension is defined as a significant drop in blood pressure, a drop in systolic blood pressure of more than 20mmHg, or a drop in diastolic blood pressure of more than 65,438+00 mmHg within 3 minutes of tilting or standing upright. With the obvious drop of blood pressure, patients may have dizziness, syncope or syncope aura. According to our research results, this disease is not common in children, and there is also controversy about whether the definition is applicable to children, because some researchers have found that this reaction can be seen in many normal children. The pathogenesis of the disease is still unclear. Some people think that the disease is mainly caused by autonomic nervous response disorder, so some authors classify it as autonomic nervous response disorder.
(4) Situational syncope
① Swallowing syncope: Swallowing syncope is generally related to esophageal and pharyngeal injury or glossopharyngeal nerve paralysis. This disease is not common among children. Swallowing syncope is mainly manifested as syncope or syncope precursor when children swallow or swallow overheated or supercooled food or even see food. The afferent branch of this reflex may be the sensory nerve fiber of esophagus, and the efferent vagus nerve activity reaction leads to bradycardia, sinus arrest or atrioventricular block in different degrees. This disease cannot be relieved naturally in children, but it can be treated by drugs that inhibit parasympathetic nerves, or by surgical selective vagotomy or permanent pacemaker implantation.
② Cough syncope: Dizziness, dizziness and syncope may occur when coughing. Cough syncope is common in middle-aged people with chronic lung diseases, but it can also be seen in children with asthma or wheezing. The main mechanism of this syncope is that the sudden increase of pleural pressure and intracranial pressure leads to the increase of cerebrospinal fluid pressure, which leads to the decrease of cerebral blood flow and the relaxation of reflex peripheral blood vessels. Actions similar to "Valsava" can lead to a decrease in cardiac output and reflexively cause vagal nerve excitation and atrioventricular block.
③ Urinary syncope: Urinary syncope refers to syncope that can occur before, during and after urination. Can occur in adolescents and the elderly, more common in boys. Risk factors include eating less, recent history of upper respiratory tract infection and drinking. Syncope usually occurs at night or when urinating after waking up. Children usually faint immediately after urinating, and there are few signs of syncope. Recurrent attacks of this disease are rare. The cause of voiding syncope is not clear, and it is speculated that its mechanism includes cardiac inhibition caused by vagus nerve stimulation and bladder filling exciting visceral afferent nerve. This kind of syncope is rarely repeated, so it generally does not need treatment.
④ Defecation syncope: Syncope or precursor of syncope during defecation is called defecation syncope. This often suggests that there are potential digestive tract diseases, cardiovascular diseases or cerebrovascular diseases. It can appear in children or recur, and we should actively look for the primary disease for such children.
⑤ "combing hair" syncope: This kind of syncope mostly occurs in women, and often occurs when children comb their hair, brush their teeth or blow dry their hair. Because its mechanism is different from the typical vasovagal syncope, including the stimulation of the scalp to excite the trigeminal nerve, the compression of the carotid baroreceptor, and the obstruction of the blood flow of the basilar artery when lowering the head or raising the head, it is separated from other vasovagal syncope. In children, this disease usually occurs after a hot bath, when the surrounding blood vessels have dilated. The upright tilt test is usually positive. The treatment only needs to drink proper amount of water to prevent insufficient blood volume, and dry your body before combing your hair.
(5) Carotid sinus hypersensitivity: Carotid sinus hypersensitivity is rare in children, but its incidence is about 10% in the elderly. The occurrence of syncope is mainly due to the excessive excitement of vagus nerve caused by mild compression of carotid sinus, which leads to sinus bradycardia, sinus arrest or atrioventricular block, leading to syncope attack. Convulsive seizures with transient loss of consciousness are difficult to distinguish from vasovagal syncope, and vasovagal syncope with headache, dizziness and nausea is also difficult to distinguish from migraine. Moreover, some vasovagal syncope attacks can also be manifested by secondary hypoxia in the brain, which is called spastic syncope. It is difficult for pediatric cardiologists and neurologists to distinguish between the two situations.
(1) The distinction between convulsive attack and syncope attack: Some studies have also found that the best distinction between syncope attack and convulsive attack is that the patient with syncope attack has no disorientation afterwards, while the author of convulsion has disorientation. In addition, people who have nausea and sweating before the incident often prompt syncope attacks, not convulsions. Loss of consciousness in supine position, rigidity of limbs or clonic movement are generally manifestations of convulsions. Sheldon et al, through the quantitative study of the medical history of patients with syncope and convulsion, put forward the medical history scoring standard to distinguish syncope and convulsion. The study of EEG can also distinguish whether a child has a seizure or a convulsive syncope. Seizure EEG showed epileptic waves; The typical manifestation of convulsive syncope is that there is no electrical abnormality in EEG during syncope attack and cardiac arrest for 3~6 seconds; However, 7~ 13 seconds after cardiac arrest, bilateral or synchronous slow waves appeared on EEG, and the patient also lost consciousness at this time; When the heart stops for more than 14 seconds, the patient may have a generalized tonic attack, and the EEG shows "flat" electrical activity. The time of cardiac arrest in children is shorter than that in adults. Studies have shown that when the heart stops beating for more than 10 seconds, a typical hypoxic convulsion will occur after loss of consciousness.
(2) Differentiation between migraine and syncope Some migraine attacks (especially those related to basilar artery) are difficult to distinguish from vasovagal syncope, and vasovagal syncope with headache, dizziness and nausea is also difficult to distinguish from migraine. Syncope migraine usually has obvious aura, followed by obvious headache. Moreover, children with migraine have obvious family history. However, some studies have found that vasovagal syncope and migraine can occur at the same time.
(3) Narcolepsy is a rare disease of teenagers, mainly manifested as excessive, inappropriate and uncontrollable sleep during the day. The disease will collapse when it is suddenly frightened or emotionally shocked. Although the disease is similar to syncope attack, it is unconscious when it collapses. The family history of narcolepsy and the response to language stimuli during the attack can be distinguished from syncope.
(4) Hold your breath and spell reading According to foreign research, 5% of children have syncope attacks. Although most children have no special breathing changes when they hold their breath, most of them occur after being slightly injured or losing their temper, crying or crying. Seizures are divided into two types: one is pale, and the typical seizure is after a short crying; One is cyanosis, and the typical attack is after crying for a long time. Although it is difficult to record, the pale breath-holding attack is caused by a brief cardiac arrest. The most likely mechanism of cyanotic breath-holding attack is similar to syncope. Due to hyperventilation caused by crying and Valsalva effect caused by silent crying, venous reflux will be reduced, and hypotension and cerebral ischemia will cause consciousness disorder. Typical breath-holding attacks occur in infants from June to 2 years old. And fortunately, most diseases will be relieved naturally when they are 3~4 years old. Although the attack is very worrying, it generally does not cause such serious consequences as sudden infant death.
The standard score to distinguish the history of convulsion and syncope is biting the tongue during the attack.
I had hallucinations before the attack.
Lose consciousness after emotional stimulation
After the attack, disorientation appeared.
Lose consciousness and lean to one side ahead.
The limbs twitched during the attack and could not be recalled after the attack.
Precursors such as hyperhidrosis appear before the attack.
Often have dizziness and other symptoms.
Seizures are related to standing or sitting for a long time.
1
1
1
1
1
-2
-2
-2 If the score is ≥ 1, support the patient to have an epileptic seizure; If the score is
Hysterical syncope is similar to loss of consciousness, which is more common in female adolescents and usually occurs when they are nervous. These children's heart rate, blood pressure and skin color have not changed during the attack, and the attack often lasts for a long time. Sick children often fall down slowly during the attack without physical harm. Physical therapy of VVS mainly includes two methods: one is to perform anti-pressure actions when patients have aura of syncope, that is, to perform isometric contraction of limbs muscles [such as crossing legs and increasing muscle tension of upper limbs, such as stretching arms and clenching fists] and other anti-pressure actions, which can enhance skeletal muscle pumping, increase venous concentric blood volume and increase cardiac output, so it is regarded as a treatment method of VVS. Studies have shown that the simultaneous contraction of the upper and lower limbs for 30 seconds before upright tilt can increase the average arterial pressure of VVS patients from 65 mm Hg to 106 mm Hg, effectively preventing syncope [12]. Another study showed that in the initial stage of HUT-induced symptoms, the systolic blood pressure of the study group increased by holding hands tightly and keeping upper limb muscles tense for 2 min, while that of the control group decreased, and 37% and 89% of the patients in the two groups had syncope attacks respectively. By taking this anti-stress effect when the precursor symptoms of syncope appeared, only 1 of 95 VVS patients had syncope attacks during the clinical follow-up.
The second physical therapy of VVS is tilt training (TT). Repeated tilt training can improve patients' tolerance to upright posture, and may restore patients' abnormal pressure reflex activity. For therapeutic TT, patients with positive tilt table test are trained in the hospital first, and the method is similar to that of upright tilt table test. When patients undergo negative tilt training twice in a row, they can leave the hospital and start family training. The method of family training is to instruct patients to keep their backs close to the wall and their feet off the wall 15cm. With the care of family members, the training time can be gradually increased from 15 minutes to 30 ~ 45 minutes, and it needs 1~2 times a day. The research results of several centers show that this training method has a very satisfactory effect on the treatment of vasovagal syncope. However, some studies have found that the compliance of this treatment method is poor and it is difficult to achieve the expected curative effect.
There are few systematic reports on the application of the above physical therapy methods in children with VVS, and its treatment methods and curative effects need to be discussed. However, because the above methods have no risk or little risk, the current research results support that they are effective and cost-free, so they should be recommended as basic treatment methods for children. (1) therapy of increasing salt and liquid intake: increasing salt and liquid intake in diet is the basis of treating VVS. Because increasing salt intake can increase extracellular fluid volume and plasma, thus reducing hemodynamic changes caused by body position change. Younoszai and others also found that oral liquid therapy for 28 children with VVS can obviously reduce the incidence or relieve the symptoms of children. We also found that health education for children with VVS, including increasing the intake of salt and water, can alleviate the symptoms of 20% children. Because supplementing salt and increasing fluid intake are relatively safe and easy to be accepted by children and parents, it is highly recommended as the initial treatment for children with VVS.
(2) Beta blockers: These drugs are the most commonly used drugs to treat children's VVS. It can play a role by reducing the stimulation of cardiac baroreceptor or blocking the effect of high level catecholamine in circulation. In the past, many studies found that β -blockers (mainly atenolol or metoprolol) can effectively treat children's VVS, and our research group also discussed its efficacy [17]. Recently, our research group conducted a meta-analysis of Chinese and English literatures on the treatment of VVS with β -blockers worldwide, and found that β -blockers may be effective drugs for the treatment of VVS. Recently, however, a randomized, double-blind placebo-controlled study of adult VVS patients found that beta blockers may not be effective in treating VVS patients. Sheldon et al discussed the trial of metoprolol in preventing syncope in adult VVS patients. Participants: 208 patients with VVS (average age 4265438 08). A double-blind randomized placebo-controlled design was used. Treatment group (n= 108) and control group (n= 100). The results showed that there was no significant difference between the two groups in preventing the recurrence of syncope. In view of the inconsistency of this research result, we also discussed it, and found that in the process of HUT, there was an obvious increase in heart rate before the positive reaction (heart rate was higher than the basic value >; 30 times per minute) it may be more effective to choose beta blockers.
(3) α -receptor agonist: This drug plays a therapeutic role by increasing peripheral blood vessel contraction and reducing venous blood volume. Strieper et al studied the therapeutic effect of phenylephrine on children with VVS. They gave 65,438+06 VVS children phenylephrine (60 mg/day, twice a day). After an average of 65,438+065,438+0.7 months' follow-up, HUT showed that 65,438+05 children were asymptomatic again. In addition, Midodrine is a selective receptor agonist, and many studies have shown that Midodrine is effective in the treatment of refractory VVS. Our research group also discussed the therapeutic effect of Midodrine on children with VVS. 26 children with VVS (repeated syncope, HUT positive) (average age 65438 02.2 2.9 years old) were divided into two groups: Midodrine group and basic treatment group (including education and suggestions to increase salt and water intake), and were followed up for 6 months. The results showed that the negative rate of HUT in the two groups was 75% and 20% respectively, and the negative rate of HUT in Midodrine group was significantly higher than that in the basic treatment group (P
(4) Fluhydrocortisone: This drug can increase the blood volume by increasing the reabsorption of sodium salt by the kidney, and it can also affect the sensitivity of baroreceptors, increase the response of vasoconstrictors, and reduce the activity of parasympathetic nerves to play a therapeutic role. However, the conclusion of this drug in treating children's VVS is also inconsistent. Some studies have found that the application of this drug can obviously improve the symptoms of children with VVS and reduce the recurrence of syncope. However, Salim et al. used a randomized, double-blind, placebo-controlled research method to explore ways to prevent the recurrence of syncope in children with VVS by taking fluhydrocortisone and increasing salt intake, but found that taking fluhydrocortisone in children could not reduce the recurrence of syncope.
(5)5-HT proactive inhibitors: These drugs can increase the concentration of 5-HT in the synaptic cleft, reduce the compensatory 5-HT receptor in the postsynaptic membrane, and weaken the central response to the rapid change of 5-HT, thus weakening the rapid inhibitory response of sympathetic nerves and preventing syncope attacks. The reports on the application of VVS in children are all empirical reports, and there is no randomized controlled study. For example, Grubb et al. administered sertraline, a proactive inhibitor of 5-HT, to 65,438+07 children with unexplained syncope and positive HUT (50mg/d), of whom 9 children disappeared during the follow-up of 65,438+02 5 months, and repeated HUT was negative. Lenk et al. reported 15 children with unexplained syncope and HUT positive received sertraline treatment. After 7 3 months' follow-up, 1/2 children had no syncope attack and repeated HUT negative, and 3 of them stopped taking drugs because they could not tolerate drugs. The effectiveness of this drug in the treatment of children with VVS needs to be further confirmed by more scientific randomized controlled studies. Moreover, these drugs are all antipsychotic drugs, which are not easy for children and parents to accept. The VSOVAGAL PACKER study (VPS) in North America shows that the use of dual-chamber pacemakers can significantly reduce the recurrence of syncope. However, VPS randomized double-blind trial showed that pacing therapy was ineffective in preventing syncope recurrence in VVS patients. A similar study from Europe, vasovagal syncope and pacing test (Synpace) also found that pacing therapy was ineffective in preventing syncope recurrence in VVS patients. However, the above studies are all from the results of adult patients, and there are few reports on the application of pacing in the treatment of VVS in children.