Shi Lin, Lin Yao, Wang Yun, Ma Li-juan, Zheng Tong, Li Lu-ping, Li Jing, Pan Yan, Wang Tian-you
Children's Hospital Affiliated to Capital Institute of Pediatrics, Beijing 100020, China.
Zhonghua Er Ke Za Zhi. 2010 Jan;48(1):39-43.
To investigate clinical features of childhood vasovagal syncope (VVS) and the possible relationship between changes of plasma and platelet 5-hydroxytryptamine (5-HT) and childhood VVS.
Forty-one children who were diagnosed as VVS because of positive head-up tilt test (HUTT) in Capital Institute of Pediatrics were enrolled as HUT-positive group, while 36 healthy children as control group. Clinical features of all children were analyzed, and blood samples of all children were obtained. Plasma and platelet 5-HT was measured by enzyme-linked immunosorbent assay (ELISA).
(1) The mean age of 41 VVS children was (10.5 +/- 1.8) years, and there were more girls than boys with the boys to girls ratio of 1:1.4. (2) Presyncopal symptoms occurred in 33 patients (80.4%), among whom dizziness had a high rate: 78.8%. (3) Commonly, there were some provocation factors before syncope, among which long-time standing was the most common one with the rate of 91.7%. (4) The mean time of positive response in BHUT and SNHUT were (20.6 +/- 8.6) minutes and (5.0 +/- 2.2) minutes, respectively. Duration of syncope was shorter than 5 minutes. (5) HUTT positive response included vasodepressor type with the rate of 61.0%, cardioinhibitory type with 14.6%, and mixed type with 24.4%. (6) There were no significant differences in baseline heart rate, systolic blood pressure and diastolic blood pressure between VVS children and healthy children. And it was the same among different types of VVS children. (7) There were no significant differences in plasma 5-HT between VVS group of baseline or HUTT-positive and control group [(27.51 +/- 1.32) microg/L vs.(27.28 +/- 2.48)microg/L, t = 0.518, P = 0.606; (27.51 +/- 1.32) microg/L vs.(28.05 +/- 1.40) microg/L, t = 2.044, P = 0.167]. There were no significant differences in platelet 5-HT concentration between VVS group of baseline and control group [(82.30 +/- 6.06) 10(9) ng/L vs. (79.88 +/- 5.79) 10(9) ng/L, t = 1.788, P = 0.780].(8) HUTT-positive platelet 5-HT concentration of VVS children was significantly higher than baseline value [(97.90 +/- 6.59) 10(9) ng/L vs. (82.30 +/- 6.06) 10(9) ng/L, t = 11.26, P = 0.00].
There were no significant changes in plasma 5-HT in children with VVS during baseline, syncope or pre-syncope, which suggests that plasma 5-HT might not be valuable for the prediction of syncope trigger. However, platelet 5-HT of VVS children was obviously higher during syncope and presyncope, which suggests that central serotonergic system might be involved in the pathogenesis of VVS.
探讨儿童血管迷走性晕厥（VVS）的临床特征以及血浆和血小板5-羟色胺（5-HT）变化与儿童VVS之间的可能关系。
选取首都儿科研究所因直立倾斜试验（HUTT）阳性而诊断为VVS的41例儿童作为HUT阳性组，36例健康儿童作为对照组。分析所有儿童的临床特征，并采集所有儿童的血样。采用酶联免疫吸附测定（ELISA）法检测血浆和血小板5-HT。
（1）41例VVS儿童的平均年龄为（10.5±1.8）岁，女孩多于男孩，男女性别比为1∶1.4。（2）33例患者（80.4%）出现晕厥前症状，其中头晕发生率较高：78.8%。（3）通常，晕厥前存在一些诱发因素，其中长时间站立最为常见，发生率为91.7%。（4）基础直立倾斜试验（BHUT）和精神心理性直立倾斜试验（SNHUT）的平均阳性反应时间分别为（20.6±8.6）分钟和（5.0±2.2）分钟。晕厥持续时间短于5分钟。（5）HUTT阳性反应包括血管减压型，发生率为61.0%；心脏抑制型，发生率为14.6%；混合型，发生率为24.4%。（6）VVS儿童与健康儿童的基础心率、收缩压和舒张压无显著差异。不同类型的VVS儿童之间也是如此。（7）VVS组基线或HUTT阳性时的血浆5-HT与对照组无显著差异[（27.51±1.32）μg/L对（27.28±2.48）μg/L，t=0.518，P=0.606；（27.51±1.32）μg/L对（28.05±1.40）μg/L，t=2.044，P=0.167]。VVS组基线时的血小板5-HT浓度与对照组无显著差异[（82.30±6.06）×10⁹ ng/L对（79.88±5.79）×10⁹ ng/L，t=1.788，P=0.780]。（8）VVS儿童HUTT阳性时的血小板5-HT浓度显著高于基线值[（97.90±6.59）×10⁹ ng/L对（82.30±6.06）×10⁹ ng/L，t=11.26，P=0.00]。
VVS儿童在基线、晕厥或晕厥前时血浆5-HT无显著变化，这表明血浆5-HT对晕厥触发的预测可能无价值。然而，VVS儿童在晕厥和晕厥前时血小板5-HT明显升高，这表明中枢5-羟色胺能系统可能参与了VVS的发病机制。
