Usefulness of the Head-Up Tilt Test in Distinguishing Neurally Mediated Syncope and Epilepsy in Children Aged 5–20 Years Old

Many nonepileptic disorders may mimic epilepsy by history or clinical presentation. Neurally mediated syncope is one of the most important conditions that might be difficult to differentiate from epilepsy on clinical grounds. We investigated the value of the head-up tilt test (HUT) to diagnose syncope in epileptic children. We studied 40 patients (18 girls and 22 boys) between 5 and 20 years old (mean, 11.5 ± 3.5) who had a previous diagnosis of epilepsy. All patients underwent a HUT test. The HUT test was positive in 26 patients (65%). No statistical difference was observed between the tilt positive and negative groups in sex, age, provocating factors, associated symptoms, family history of syncope and heart disease, findings in physical examination, and electroencephalogram result. There was a history in favor of true syncope in 58% of tilt positive patients compared to 14% of tilt negative patients (p < 0.05). Also, family history of seizure was more frequent in tilt positive patients (p < 0.05). After 18 ± 6 months of follow-up, 18 of 26 patients with a positive tilt test were completely asymptomatic. Inadequate history taking and overemphasis on positive family history for seizures were important causes of misdiagnosis of epilepsy in our study. The HUT test is a simple, noninvasive diagnostic tool for distinguishing syncope and epilepsy in children and should be considered early in the diagnostic plan and for determining management of selected patients with a history of drop attack and loss of consciousness.     

β受体阻滞剂治疗儿童自主神经介导性晕厥的多中心研究

目的 探讨β受体阻滞剂对自主神经介导性晕厥儿童的治疗效果.方法 研究对象为1995年5月至2006年4月在北京、湖南、湖北、上海4地就诊或住院的103例自主神经介导性晕厥或接近晕厥患儿,其中男43例,女60例;年龄5～19岁,平均(12.0±2.6)岁.其中血管迷走性晕厥(VVS)患儿49例,体位性心动过速综合征(POTS)患儿54例.分别将VVS以及POTS患儿随机分为治疗组(口服美托洛尔治疗)和对照组(口服补液盐治疗),观察2组儿童临床晕厥发作次数及直立倾斜试验结果,采用SPSS 10.0软件进行统计学分析.结果 VVS和POTS治疗组的治愈率分别为60.61%和68.75%,对照组分别为18.75%和0.00%.两治疗组好转率分别为15.15%和15.63%,对照组为6.25%和40.91%.治疗组HUT转阴率分别为60.61%和68.75%,对照组为18.75%和9.09%.两治疗组的有效率、治愈率和HUT转阴率均明显高于对照组(P均＜0.01).结论 β受体阻滞剂对VVS患儿以及POTS患儿的治疗有效.     

儿童血管迷走性晕厥反复发作相关因素分析

目的探讨影响儿童血管迷走性晕厥(VVS)反复发作的相关因素。方法收集125例确诊为VVS患儿的临床资料,根据晕厥首次发作至直立倾斜试验之前5年内的发作次数,分为晕厥发作次数2、3次的低频次组及≥4次的高频次组,对两组患儿资料进行统计分析。结果 125例VVS患儿中,低频次组84例(67.2%),高频次组41例(32.8%)。单因素分析结果显示,直立倾斜试验检查年龄、晕厥发作时间、发作诱因、晕车史、阳性家族史是VVS高频次发作的相关因素。非条件logistic回归分析结果显示,发作诱因(OR=3.723,95%CI:1.163~11.918,P=0.027)、晕车史(OR=5.929,95%CI:2.066~17.015,P=0.001)、阳性家族史(OR=6.794,95%CI:2.006~23.013,P=0.002)是VVS高频次发作的独立危险因素。结论非持久站立引起的其他发作诱因、晕车史、阳性家族史对预测VVS患儿高频次晕厥发作具有重要临床意义。     

血管迷走性晕厥患儿40例

目的探讨不同类型血管迷走性晕厥(VVS)患儿的临床特征及实验室检查指标间的差异。方法经常规病史询问、体格检查、卧立位血压、辅助检查、直立倾斜试验(HUT)确诊的VVS患儿40例,比较不同类型患儿的临床特征及实验室指标间的差异。结果VVS患儿的血流动力学类型以血管抑制性为主。不同类型VVS患儿的临床特征,包括晕厥的诱因、先兆、发作频率、持续时间、基础心率、血压及血清电解质水平等均无显著差异。结论血管抑制型反应是血管迷走性晕厥患儿的主要血流动力学类型。     

一氧化氮和内皮型一氧化氮合成酶与血管迷走性晕厥发病的关系

目的：探讨一氧化氮和内皮型一氧化氮合成酶与儿童血管迷走性晕厥发病的关系。方法：血管迷走性晕厥患儿14例（A组）,其他原因引起晕厥患儿10例（B组）,健康志愿者20例（C组）。于倾斜试验（HUT）前和倾斜不同时间测定A组与B组患儿的血浆一氧化氮（NO）水平,同时对3组儿童进行内皮型一氧化氮合成酶（eNOS）基因G894T多态性检测。结果：①A组患儿出现阳性反应时血浆NO水平较平卧时显著升高（76.7±9.6 vs 90.0±11.4 μmol/L, P<0.05）;②A组患儿在症状好转后血浆NO水平较试验前显著降低（82.7±9.2 vs 61.5±6.9 μmol/L,P<0.01）;③B组患儿倾斜时血浆NO水平较平卧时差异无显著性;④A,B两组患儿的血压、心率变化与NO水平无显著相关性;⑤A组患儿eNOS基因G894T突变型基因频率显著高于B组与C组(42.9% vs 10%, P<0.05)。结论： 倾斜体位时血浆NO水平异常升高可能参与了血浆血管迷走性晕厥的发病机制,而其升高水平可能与eNOS基因G894T多态性表达有关。     

The efficacy of midodrine hydrochloride in the treatment of children with vasovagal syncope

OBJECTIVE: To determine whether midodrine hydrochloride therapy can prevent vasovagal syncope (VVS) in pediatric patients. STUDY DESIGN: Children with recurrent syncope (n = 26) were randomly assigned into 2 groups. Group I comprised children given midodrine hydrochloride as first-line therapy in addition to conventional therapy, and group II comprised patients receiving conventional therapy only. Repeat head-up tilt (HUT) testing and follow-up of least 6 months were conducted to evaluate the therapeutic effectiveness and side effects of midodrine in treating VVS in children. RESULTS: The HUT-based effective rate was significantly higher in group I than in group II (75% vs 20%; P < .05). During the follow-up period, the recurrence of syncope was significantly lower in group I than in group II (P < .05). CONCLUSIONS: Midodrine hydrochlorate is effective in treating VVS in children, especially in preventing recurrent episodes. Few side effects were observed in the present study.     

Sublingual Isosorbide Dinitrate-Stimulated Tilt Test for Diagnosis of Vasovagal Syncope in Children and Adolescents

Vasovagal syncope is the most likely cause of syncope in the young. Head-up tilt-table test (HUT) provides the ability to provoke vasovagal syncope under controlled laboratory settings. In adult populations, pharmacologic stimulation with intravenous/sublingual isosorbide dinitrate (ISDN) has been shown to be an alternative to isoproterenol for increasing the diagnostic yield of HUT. In this study, 40 patients aged 9-18 years with unexplained syncope and 12 healthy age-matched children were evaluated by HUT to 70 degrees for 45 minutes. If tilting alone did not induce symptoms (syncope and presyncope), 0.1 mg/kg ISDN was given while the patient lay supine. After 5 min, the table was tilted to 70 degrees for 15 min or until the symptoms occurred. The control group consisted of 12 healthy age-matched children studied in a similar manner. Six patients (15%) had a positive basal tilt test. Twenty-five patients (62.5%) lost consciousness following ISDN administration. In the control group, nobody had a syncopal episode during the basal tilt test. However, ISDN administration resulted in 1 positive response (8.3%). The sensitivity of the test was 77.5% and its specificity was 91.6%. It is concluded that sublingual nitroglycerin HUT is suitable for routine clinical practice in children and adolescents with unexplained syncope.     

Association of Clinical Characteristics of Unexplained Syncope with the Outcome of Head-Up Tilt Tests in Children

The aim of this study was to clarify the association of clinical characteristics of unexplained syncope with the outcome of the head-up tilt test (HUT) in children. A total of 47 patients with unexplained syncope were classified into two groups according to their outcomes of HUT: the positive response group and the negative response group. We reviewed their clinical data as well as the results of HUT and analyzed them with logistic regression method. The results showed that the incidence of positive responses to HUT was higher in girls than in boys (8/22 vs 10/7, p < 0.05). Compared with fainted children younger than 12 years of age, 12- to 16-year-old adolescents with unexplained syncope had a high positive outcome of HUT (30 vs 72.9%, p < 0.05). Compared with fainted children with negative response of HUT, children with positive response to HUT often had syncope in special circumstances (e.g., prolonged standing, anxiety and fright, and morning exercise), and they often had prodrome, such as pallor, lightheadedness, and nausea (28/30 vs 8/17, p < 0.05). However, the number and duration of syncopal spells did not relate to the positive responses to HUT. The logistic regression analysis showed that three factors significantly influenced the outcome of HUT: predisposing factors of syncope, prodrome of syncope, and age (p < 0.05; OR = 32.9434, 17.7281, and 2.7842, respectively). Hence, if pubertal girls with unexplained syncope had clear predisposing factors and prodromes, they were likely to have positive responses to HUT, and they were likely to be clinically considered as having vasovagal syncope.     

儿童血管迷走性晕厥的诊断与治疗

血管迷走性晕厥(VVS)占儿童不明原因晕厥的80%.VVS需经详细询问病史、体格检查及实验室检查,排除引起晕厥的器质性疾病后,行直立倾斜试验(HUTT)得以诊断.VVS的治疗方法 主要包括非药物治疗(健康教育、直立训练、口服补液盐)、药物治疗(β受体阻滞剂、α受体激动剂、氟氢可的松、5-羟色胺再摄取抑制剂、血管紧张素转换酶抑制剂等)及起搏器治疗等.     

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目的探讨鉴别血管迷走性晕厥(VVS)及体位性心动过速综合征(POTS)的临床依据。方法 2009年4月至2011年4月于北京大学第一医院儿科门诊就诊并确诊为VVS的儿童40例,年龄6～18岁,平均(11.8±2.9)岁;POTS儿童165例,年龄5～19岁,平均(11.4±2.7)岁。评价与检查手段包括临床表现、家族史、生活习惯、直立试验以及直立倾斜试验。结果 VVS和POTS在儿童时期的共同特征包括学龄期及青春期多发、女孩稍多于男孩、发作季节以夏秋季多见、多数患儿有诱因和发作先兆、发作后仍有不适、平卧后症状可缓解。在VVS儿童中以晕厥为主要表现者明显多于POTS(P<0.001),在POTS儿童中,以头晕为表现的患儿明显多于VVS(P<0.001)。VVS患儿中父方有直立不耐受家族史者明显多于POTS患儿(P<0.05)。结论直立倾斜试验是鉴别VVS与POTS的重要客观检查手段。晕厥及头晕的发生频率对于临床鉴别诊断VVS与POTS具有参考价值。     

儿童体位性心动过速综合征合并血管迷走性晕厥的诊断探讨

目的：探讨儿童体位性心动过速综合征（POTS）合并血管迷走性晕厥（VVS）的诊断。方法：回顾性地复习2007年1月至2010年12月经直立倾斜试验（HUT）诊断为POTS的57例儿童的临床资料,其中男29例,女28例,年龄5～16(12.2±1.9)岁。结果：57例POTS儿童中,在可以耐受倾斜体位的前提下,通过延长HUT时间,24例(42%)经HUT诊断合并VVS,其中血管抑制型20例,混合型3例,心脏抑制型1例。合并VVS儿童平均年龄（13.0±1.4岁）大于未合并VVS的POTS儿童（11.5±2.1岁）,差异有统计学意义（P0.05）。结论：部分POTS儿童合并VVS,在可以耐受倾斜体位的前提下,延长HUT时间有利于防止VVS漏诊。与未合并VVS的POTS儿童比较,合并VVS儿童年龄较大,但性别、临床症状无明显差异。     

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目的探讨米多君对血管迷走性晕厥儿童的治疗效果。方法将2003-07—2004-12在北京大学第一医院儿科就诊的46例晕厥反复发作、直立倾斜试验(HUT)阳性的血管迷走性晕厥患儿,分为米多君组、美托洛尔组及基础治疗组。首先应用HUT评价患儿的治疗反应及调整药物,所有患儿随访6个月后,如没有晕厥的发作者则停药,并继续随访。进一步评价患儿晕厥复发情况及药物的不良反应。结果米多君组、美托洛尔组及基础治疗组3组患儿HUT转阴率分别为75·0%、65·0%及20·0%。米多君组及美托洛尔组患儿的HUT转阴率明显高于基础治疗组(P均<0·05),而给药治疗的两组患儿的HUT转阴率差异无显著性(P>0·05)。在随访过程中,米多君组及美托洛尔组晕厥复发率分别为22·2%及30·7%,而基础治疗组的晕厥复发率为80·0%,前两组晕厥复发率显著低于后组(P均<0·05)。前两组之间的复发率差异无显著性(P>0·05)。结论米多君可有效治疗血管迷走性晕厥儿童。     

The diagnostic protocol in children and adolescents with syncope: a multi-centre prospective study

Aim: The appropriate diagnostic protocol for children with syncope has not been well established. A diagnostic protocol was developed and prospectively implemented to improve the diagnostic performance of paediatricians.
Methods: The study population included 474 consecutive patients (range 6–17 years) presenting with a syncopal spell in one of the five participating hospitals of China. In step 1, all patients underwent initial evaluation for history, physical examination, standing test and standard electrocardiography (ECG). In step 2, priority was given to cardiographic tests for possibly cardiogenic syncope, or electroencephalographic examination and brain imaging for suspected neurological syncope, or psychiatric tests for suspected psychiatric syncope. Patients with unexplained syncope underwent head-up tilt testing (HUT).
Results: The initial evaluation gave a definite diagnosis in 59 (12.4%) and possible diagnosis in 54 of the 474 patients. Further testing gave a definite diagnosis for 326 patients (69.7%). After the entire diagnostic protocol, definite diagnosis was established in 385 patients (81.1%). Autonomic-mediated reflex syncope (AMS) accounted for 73.0% of cases. The average cost of diagnostic results per patient was RMB 1030.24 ± 150.09 ($118.42 ± 17.25).
Conclusion: The use of a simplified diagnostic protocol for children and adolescents with syncope improves diagnostic yield.     

舌下含化硝酸甘油直立倾斜试验对儿童不明原因晕厥的诊断研究

目的 探讨舌下含化硝酸甘油直立倾斜试验对不明原因晕厥患儿的诊断价值。方法 对25例不明原因晕厥的患儿(晕厥组)及10例无晕厥史的正常健康儿童(对照组)先行基础直立倾斜试验,阴性者再行舌下含化硝酸甘油直立倾斜试验(4～6μg／kg,最大量不超过300μg)。结果 基础直立倾斜试验在晕厥组的阳性率为48％(12／25),对照组为0;舌下含化硝酸甘油直立倾斜试验在晕厥组阳性率为80％(20／25),对照组为20％(2／10);舌下含化硝酸甘油直立倾斜试验诊断的敏感度、特异度及诊断价值均为80％。两组患儿中仅有1例在试验中出现头痛,但能坚持试验完成。结论 舌下含化硝酸甘油直立倾斜试验对诊断儿童血管迷走性晕厥具有良好的敏感性和特异性,且具有操作简便、不良反应小的特点。值得推广应用。     

血管迷走性晕厥和5-羟色胺能系统

5-羟色胺(5-HT)在血管迷走性晕厥(VVS)中的作用备受关注.5-HT是一种神经递质,广泛分布于中枢神经系统,突触后膜有多种5-HT受体,其中,5-HT1A受体介导中枢降压机制,同时能够促进催乳素、促肾上腺皮质激素等释放.短时应用选择性5-羟色胺重摄取抑制剂(SSRI)于药物激发的直立倾斜试验(HUT),能够抑制突触间隙对5-HT的重摄取,突触间隙5-HT浓度升高,诱发晕厥发作,提高HUT试验的敏感性.长期应用SSRI则可下调突触后膜5-HT受体,减弱对中枢5-HT快速变化的反应,从而减弱对交感神经的快速抑制反应,预防晕厥发作.中枢5-羟色胺能系统可能参与了VVS的发病机制,SSRI对VVS的诊断及治疗有重要价值.     

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??Objective To discuss the changes of ambulatory blood pressure monitoring??ABPM?? in children with vasovagal syncope ??VVS??.Methods A total of 72 children ??VVS group??32 males??40 females??mean age ??10.98±1.86??years?? were enrolled in this study??who came from Children Syncope Outpatient Department or Inpatient Department of the Second Xiangya Hospital of Central South University from Sep 2008 to Feb 2010.After confirmed diagnosis of VVS by positive head-up tilt test ??HUTT????each patient was given ABPM.Forty healthy children ??19 males??21 females??mean age 10.24 ± 2.01 years?? were as controls ??control group??.Parameters of ABPM in children were analyzed.SPSS 17.0 software was used for the statistical analysis of these data.Results ??1??Mean pressure??24-hour mean systolic pressure ??24hSBP????24-hour mean diastolic pressure ??24hDBP????daytime mean systolic pressure ??DSBP?? and nighttime mean systolic pressure ??NSBP?? in VVS group were higher than those of the control group ??P??0.05??.??2??Blood pressure pattern??the ratio of non-spoon pressure pattern was higher than that of spoon pressure pattern with VVS ??67%vs.18%??P ??0.05??.NDBP ??P??0.05?? and NSBP ??P ??0.05?? were decreased and the systolic pressure differences and diastolic pressure differences in the daytime and at nighttime were higher in spoon pressure pattern than those of non-spoon pressure pattern with VVS ??P??0.05??.??3??Diagnostic experimental evaluation??the specificity??sensitivity??diagnostic coincidence??positive predict value and negative predict value of non-spoon pattern of ambulatory blood pressure pattern to VVS was 82.5%??66.67%??72.32%??87.27% and 57.89%??respectively.The Youden index was 45.28%.Conclusion There is autonomic nerve adjustment imbalance in children with VVS during asymptomatic time periods??especially the sympathetic nerve.The non-spoon pattern rate of fluctuation curve of ambulatory blood pressure in VVS children is higher??which is of diagnosis value to VVS children.     

儿童直立倾斜试验血流动力学变化与身高、体重及体质量指数的关系

目的 探讨儿童直立倾斜试验（HUTT）血流动力学变化与身高、体重及体质量指数（BMI）的关系.方法 收集2000年1月至2012年8月在中南大学湘雅二医院儿童晕厥专科 门诊就诊或住院的不明原因晕厥、头痛、头晕、胸闷、叹气等儿童1 906例,男964例,女942例,年龄2.00 ～ 17.92岁,平均10.84±2.97）岁.测量身高、体重,计算BMI.在取得受试者或监护人书面知情同意后,进行HUTT.根据HUTT结果及反应类犁分HUTT阴性组、体位性心动过速综合征（POTS）组、血管迷走性晕厥（VVS）血管抑制型组、VVS心脏抑制型组、VVS混合型组.结果 与HUTT阴性组相比,年龄在POTS组、VVS血管抑制型组、VVS混合型组较大（P＜0.05）,身高、体重、体表面积在POTS组、VVS血管抑制型组、VVS混合型组增加（P＜0.01）.与POTS组相比,体重、体表面积在VVS血管抑制型组、VVS混合型组降低（P＜0.05）,VVS心脏抑制型组与其他各组比较差异未见统计学意义（P＞0.05）.结论 儿童HUTT血流动力学变化与身高、体重及BMI存在一定关系.     

儿童血管迷走性晕厥的临床特征及血浆和血小板中5-羟色胺的变化

目的 探讨小儿血管迷走性晕厥的临床特征和血浆、血小板中5-羟色胺(5-HT)的变化.方法 2006年10月-2009年2月在首都儿科研究所经直立倾斜试验(head-up tilt test,HUTT)确诊为血管迷走性晕厥(VVS)患儿41例(HUTT阳性组),诊断标准参照基础HUTT对儿童不明原因晕厥的诊断研究,男17名,女24名,年龄6～14岁,平均年龄(10.5 ±1.8)岁.匹配健康儿童(对照组):当地幼儿园和中小学36名健康小儿,男16名,女20名,年龄9～14岁,平均年龄(10.7±1.5)岁.分析晕厥诱因和先兆症状、HUTT反应方式、晕厥发作时间、VVS患儿静息状态各亚型血压和心率变化等临床特点.全体研究对象抽取静脉血3 ml,用双抗体夹心酶标免疫分析(ELISA)法对41例血管迷走性晕厥患儿及36名健康儿童的血浆和血小板中5-HT进行测定.结果 ①41例血管迷走性患儿平均年龄为(10.5±1.8)岁,女童比例高于男童,为1.4:1.②VVS先兆症状:患儿中33例存在晕厥先兆(80.4%),其中头晕发生率高达78.8%.③VVS发生诱因:儿童VVS发作前常存在诱发因素,包括:长久站立、劳累、情绪影响等.其中长久站立比例最高,达90.2%.④HUTT平均反应时间及晕厥持续时间:基础直立倾斜试验(BHUT)阶段平均反应时间为(20.6±8.6)min;舌下含化硝酸甘油激发倾斜试验(SNHUT)阶段平均反应时间(5.0±2.2)min.晕厥持续时间均短于5 min.⑤HUTT不间反应类型的分布:血管抑制型61.0%,混合型24.4%,心脏抑制型14.6%.⑥血压和心率的比较:VVS患儿和正常儿童静息状态下基础心率、收缩压、舒张压相比差异无统计学意义;VVS患儿中血管抑制型、混合型和心脏抑制型静息状态下基础心率、收缩压、舒张压相比差异无统计学意义.⑦VVS患儿基础状态和HUTT阳性时血浆中5-HT较对照组差异无统计学意义[(27.51±1.32)μg/Lvs.(27.28±2.48)μg/L,t=0.518,P=0.606;(27.51±1.32)μg/L vs.(28.05 ±1.40)μg/L,t=2.044,P=0.167],基础状态下血小板5-HT与对照组之间差异无统计学意义[(82.30 ±6.06)10~9ng/L vs.(79.88±5.79)10~9ng/L,t=1.788,P=0.780].⑧VVS患儿基础状态下和HUTT阳性时的血小板5-HT比较差异有统计学意义[(82.30±6.06)10~9ns/L vs.(97.90±6.59)10~9ng/L,t=11.26,P=0.00].结论 VVS患儿具有明显的临床特征;VVS患儿基础状态和晕厥(或晕厥先兆发生时)血浆中5-HT变化不明显;VVS患儿晕厥或晕厥先兆发生时血小板5-HT明显升高,提示中枢5-HT系统可能参与了VVS的发病过程.     

血管迷走性晕厥患者心电图改变研究进展

部分血管迷走性晕厥(VVS)患者在直立倾斜试验(HUTT)诱导晕厥发作过程中出现各种心律失常,其中以缓慢性心律失常最为常见.心电图各波形态在HUTT阳性和HUIT阴性VVS患者间也有所不同,其主要原因与VVS患者本身存在自主神经功能紊乱有关.了解VVS患者的心电图改变及其对HUTT结果、治疗效果及预后等各方面的预测价值将对VVS的临床诊治提供可靠依据.     

血管迷走性晕厥患者心电图改变研究进展

部分血管迷走性晕厥(VVS)患者在直立倾斜试验(HUTT)诱导晕厥发作过程中出现各种心律失常,其中以缓慢性心律失常最为常见.心电图各波形态在HUTT阳性和HUIT阴性VVS患者间也有所不同,其主要原因与VVS患者本身存在自主神经功能紊乱有关.了解VVS患者的心电图改变及其对HUTT结果、治疗效果及预后等各方面的预测价值将对VVS的临床诊治提供可靠依据.