Incidence of Adolescent Syncope and Related Injuries Following Vaccination and Routine Venipuncture

PURPOSE

Vaccination is associated with syncope in adolescents. However, incidence of vaccine-associated syncope and resulting injury, and how it compares to syncope incidence following other medical procedures, is not known. Here, we describe the incidence of syncope and syncope-related injury in adolescents following vaccination and routine venipuncture.

METHODS

We identified all Kaiser Permanente Northwest members ages 9-18 years with a vaccination or routine venipuncture and a same-day International Classification of Diseases diagnosis of syncope from 2013 through 2019. All cases were chart reviewed to establish chronology of events (vaccination, venipuncture, syncope, and injury, as applicable) and to attribute cause to vaccination or venipuncture. Incidence rates for vaccine-associated and venipuncture-associated syncope were calculated overall, by sex and age group. Syncope events resulting in injury were assessed for each event type.

RESULTS

Of 197,642 vaccination and 12,246 venipuncture events identified, 549 vaccination and 67 venipuncture events had same-day syncope codes. Chart validation confirmed 59/549 (10.7%) events as vaccine-associated syncope, for a rate of 2.99 per 10,000 vaccination events (95% confidence interval (CI): 2.27-3.85) and 20/67 (29.9%) events as venipuncture-associated syncope, for a rate of 16.33 per 10,000 venipuncture events (95% CI: 9.98-25.21). The incidence rate ratio of vaccine-associated to venipuncture-associated syncope events was 0.18 (95% CI: 0.11-0.31). The incidence of vaccine-associated syncope increased with each additional simultaneously administered vaccine, from 1.51 per 10,000 vaccination events (95% CI: 0.93-2.30) following a single vaccine to 9.94 per 10,000 vaccination events (95% CI: 6.43-14.67) following three or more vaccines. Syncope resulted in injury in about 15% of both vaccine and venipuncture events.

DISCUSSION

Syncope occurs more commonly following venipuncture than vaccination. The number of simultaneously administered vaccines is a risk factor for postvaccination syncope in adolescents.

İnsülin Duyarlılığı ve Vücut Kitle İndeksinin Ortostatik İntolerans Üzerine Etkileri

Amaç: Çalışmanın amacı insülin duyarlılığı ve antropometrik ölçümlerin ortostatik intolerans sendromları üzerindeki etkilerini değerlendirmektir. Yöntem: Retrospektif bir çalışmadır. 7-18 yaş arası senkop öyküsü ile başvuran hastalarda insülin duyarlılık indeksleri hesaplandı ve antropometrik ölçümlerine değerlendirildi. Hastalar head-up tilt test sonuçlarına göre test pozitif ve test negatif olarak gruplandırıldı. Ayrıca tilt testi pozitif olan hastalar vazodepresör vazovagal senkop (VVS), kardiyoinhibitör VVS, mikst VVS ve postural ortostatik taşikardi sendromu olmak üzere dört alt gruba ayrıldı. Bulgular: Çalışmaya toplam 509 hasta dahil edildi. Yaş ortalaması 13,45 ± 2,82 yıldı ve %64,4'ü kızdı. Tilt testi 214 hastada pozitif, 295 hastada negatifti. Tilt testi sonuçları ile 173 hastaya VVS ve 41 hastaya (%19) POTS tanısı konuldu. İnsülin duyarlılık indekslerine göre gruplar arasında istatistiksel olarak anlamlı fark yoktu. Antropometrik ölçümlerde boy, boy standart deviasyonu, vücut kitle indeksi (VKİ) standart deviasyonu ve VKİ persentili (sırasıyla p=0,008, p=0,02, p=0,036, p=0,03) açısından iki grup arasında anlamlı farklılık gözlendi. Sonuç: Çalışmamızda özellikle genç kızlarda düşük VKİ ve uzun boylu olmak vazovagal senkop ataklarına zemin hazırlayan faktörler iken, insülin duyarlılık indeksleri ile pozitif head-up tilt test sonucu arasında ilişki bulunmadı. Tekrarlayan senkoplara neden olan faktörlere ışık tutarak uygun tedavinin sağlanması hastaların yaşam kalitelerine katkı sağlayabilir.

Prospective analysis of syncope/pre-syncope in a tertiary paediatric orthopaedic fracture outpatient clinic

BACKGROUND

The incidence of vasovagal syncope (VVS) precipitated by medical procedures such as blood donation is quoted as between 0.13% and 4.17%. Vasovagal events have been observed to occur following cast removal at our paediatric orthopaedic clinic; however, there is no available information in the existing literature regarding incidence or risk factors. This study aims to identify the incidence and demographic traits of patients experiencing syncopal events following cast removal.

METHODS

Over a 12-month period, paediatric patients experiencing a syncopal or pre-syncopal event during an outpatient appointment for cast removal were prospectively enrolled into the study. Basic demographic data were recorded, as well as injury and procedure details and a description of the event. Statistical analysis as well as calculation of incidence of vasovagal events were performed.

RESULTS

A total of 6078 patients presented for cast removal in the 12-month period. Twenty syncopal or pre-syncopal events were recorded. Incidence was calculated as 0.32%. Mean patient age was 10.8 years. Male : female ratio was 2.3:1. Mean body mass index (BMI) was 20.08, with a trend for higher prevalence of males under the 50th BMI percentile-for-age. The mean time post-injury was 31.4 days. Ninety-five percent of patients were being treated for an upper limb injury and 30% had injuries that had been treated surgically. There were no associated secondary complications or injuries.

CONCLUSIONS

Incidence of VVS following cast removal is comparable to the values quoted in literature for other medical procedures. Demographic data of our cohort suggested that those who experienced VVS were predominantly young males of lower-than-average BMI.

Body mass index is a promising predictor of response to oral rehydration saline in children with vasovagal syncope

BACKGROUND

Vasovagal syncope (VVS) greatly impairs quality of life. The therapeutic efficacy of oral rehydration saline (ORS) for unselected VVS patients is not satisfactory due to the diverse mechanisms of the disease. Body mass index (BMI) was demonstrated to reflect blood volume to a certain extent. Therefore, the present study explored the capability of BMI to predict the therapeutic response of children with VVS to ORS treatment.

METHODS

Seventy-four children with VVS who visited the Syncope Unit of Pediatrics at Peking University First Hospital from November 2010 to June 2019 receiving ORS treatment were enrolled for this retrospective case-control study. A comparison of demographic, clinical, and hemodynamic characteristics was performed between responders and non-responders. The correlation between baseline BMI and response time was analyzed. To determine the value of baseline BMI in predicting the therapeutic efficacy of ORS in children with VVS, a receiver operating characteristic curve analysis was performed.

RESULTS

Fifty-two children were identified as responders, and the remaining 22 children were identified as non-responders. The baseline BMI of the responders was much lower than that of the non-responders (16.4 [15.5, 17.8] kg/m2vs. 20.7 ±e6 kg/m2, P < 0.001), and baseline BMI was positively correlated with response time in the head-up tilt test after adjusting for sex (r = 0.256, 95% confidence interval [CI]: 0.067-0.439, P = 0.029). The area under the receiver operating characteristic curve of baseline BMI was 0.818 (95% CI: 0.704-0.932, P < 0.001), and an optimal cut-off value of 18.9 kg/m2 yielded a sensitivity of 83% and a specificity of 73% to predict the efficacy of ORS in VVS.

CONCLUSION

Prior to treatment, baseline BMI is a promising predictor of response to ORS in children with VVS.

Gut microbiota analysis and its significance in vasovagal syncope in children

Background:

Vasovagal syncope (VVS) is common in children and greatly affect both physical and mental health. But the mechanisms have not been completely explained. This study was designed to analyze the gut microbiota in children with VVS and explore its clinical significance.

Methods:

Fecal samples from 20 VVS children and 20 matched controls were collected, and the microbiota were analyzed by 16S rRNA gene sequencing. The diversity and microbiota compositions of the VVS cases and controls were compared with the independent sample t test or Mann-Whitney U test. The correlation between the predominant bacteria and clinical symptoms was analyzed using Pearson or Spearman correlation test.

Results:

No significant differences in diversity were evident between VVS and controls (P > 0.05). At the family level, the relative abundance of Ruminococcaceae was significantly higher in VVS children than in controls (median [Q1, Q3]: 22.10% [16.89%, 27.36%] vs. 13.92% [10.31%, 20.18%], Z = −2.40, P < 0.05), and LEfSe analysis revealed Ruminococcaceae as a discriminative feature (linear discriminant analysis [LDA] score > 4, P < 0.05). The relative abundance of Ruminococcaceae in VVS patients was positively correlated with the frequency of syncope (r = 0.616, P < 0.01). In terms of its correlation with hemodynamics, we showed that relative abundance of Ruminococcaceae was negatively correlated with the systolic and diastolic pressure reduction at the positive response in head-up tilt test (HUTT; r = −0.489 and −0.448, all P < 0.05), but was positively correlated with the mean pressure drop and decline rate (r = 0.489 and 0.467, all P < 0.05) as well as diastolic pressure drop and decline rate at the HUTT positive response (r = 0.579 and 0.589, all P < 0.01) in VVS patients.

Conclusion:

Ruminococcaceae was the predominant gut bacteria and was associated with the clinical symptoms and hemodynamics of VVS, suggesting that gut microbiota might be involved in the development of VVS.