Résumé
Syncope is a common emergency of children and adolescents,which has serious influence on the quality of life.Neurally-mediated syncope,including postural tachycardia syndrome,vasovagal syncope,orthostatic hypotension and orthostatic hypertension,is the main cause of syncope in children and adolescents.The main manifestations of neurally-mediated syncope are diverse,such as dizziness,headache,chest tightness,chest pain,pale complexion,fatigue,pre-syncope and syncope.Although the clinical manifestations are similar,each subtype of syncope has its hemodynamic feature and optimal treatment option.The diagnosis rate of syncope in children has been greatly improved on account of the development of the diagnostic procedures and methods.In recent years,with the promotion of head-up tilt test and drug-provocated head-up tilt test,the hemodynamic classification of neurally-mediated syncope gets continually refined.In recent years,with the effort of clinicians,an appropriate diagnostic protocol for children with syncope has been established.The initial evaluation consists of history taking,physical examination,standing test and standard electrocardiography.After the initial evaluation,some patients could be diagnosed definitely,such as postural tachycardia syndrome,orthostatic hypotension,and situational syncope.Those with a specific entity causing syncope need selective clinical and laboratory investigations.Patients for whom the cause of syncope remained undetermined should undergo head-up tilt test.The precise pathogenesis of neurally-mediated syncope is not entirely clear.In recent years,studies have shown that neurally-mediated syncope may be related to several factors,including hypovolemia,high catecholamine status,abnormal local vascular tension,decreased skeletal muscle pump activity and abnormal neurohumoral factors.Currently based on the possible pathogenesis,the individualized treatment of neurally-mediated syncope has also been studied in-depth.Generally,the management of neurallymediated syncope includes non-pharmacological and pharmacological interventions.Patient education is the fundamental part above all.In addition to exercise training,the first-line treatments mainly include oral rehydration salts,beta adrenoreceptor blockers,and alpha adrenoreceptor agonists.By analyzing the patient's physiological indexes and biomarkers before treatment,the efficacy of medication could be well predicted.The individualized treatment will become the main direction in the future researches.
Résumé
Objective:To explore the clinical characteristics of the co-morbidity of vasovagal syncope (VVS) and postural tachycardia syndrome (POTS) with allergic diseases in children.Methods:A retrospective analysis was launched to summarize the clinical data of children with VVS and POTS.They were divided into allergic group and non-allergic group according to the history of allergic diseases.The participants' clinical characteristics were compared between allergic group and non-allergic group using independent sample t test or rank sum test;composition comparisons were completed by Chi-square test.Bi-variate correlation analysis was used to explore the association between eosinophil percentage/count and symptom scores/frequency of syncope episodes.A P value ＜ 0.05 was defined as statistically significant.Results:Sixty-seven children complaining of orthostatic intolerance (43 patients diagnosed as VVS and 24 cases diagnosed as POTS) were enrolled.Totally 21 cases (31％) had allergic diseases,inclu ding allergic rhinitis,atopic eczema,asthma,as well as food allergy.And allergic rhinitis is the most common co-morbidity.There were no significant differences between the two groups in age,gender ratio,height,body weight and basement blood pressure.Compared with the non-allergic group,the allergic group showed later onset age (year) (11 ± 2 vs.9 ± 3,P ＜ 0.05) of orthostatic intolerance and shorter course of the diseases (month) [8.0 (0.1,0.1) vs.24.0 (0.1,144.0),P＜0.05].The frequency of syncope episodes in the allergic group among VVS children (times per month) [2.50 (0.08,30.00) vs.O.25 (0.03,5.00),P ＜ 0.05] was much higher than that in the non-allergic group.Additionally,the eosinophil percentage (％) [3.50 (0.70,0.59) vs.1.65 (0.30,6.20),P＜0.001] and eosino phil count (×109) [0.18 (0.05,0.71) vs.0.10 (0.02,0.38),P＜0.001] were increased in the allergic group.However,there were no remarkable differences in the results of head-up tilt test in children with VVS or in the maximum change of heart rate during standing test in children with POTS were involved.Conclusion:Allergic diseases are common co-morbidities in children with both VVS and POTS.Allergic rhinitis is the most common co-morbidity.Children with co-morbidity of VVS/POTS and allergic diseases had a later onset of symptoms of orthostatic intolerance,and were more likely to be hospitalized for intensive attacks of symptoms during a short period when compared with those without allergic diseases.Children diagnosed as VVS combined with allergic diseases had more frequent episodes of syncope.