Bradley Joseph P, Bacharier Leonard B, Bonfiglio JoAnn, Schechtman Kenneth B, Strunk Robert, Storch Gregory, Castro Mario
Department of Internal Medicine, Washington University School of Medicine, St Louis, Missouri 63110-1093, USA.
Pediatrics. 2005 Jan;115(1):e7-14. doi: 10.1542/peds.2004-0059.
Respiratory syncytial virus (RSV) bronchiolitis is a common cause of hospitalizations in children and has been increasingly identified as a risk factor in the development of asthma. Little is known about what determines the severity of RSV bronchiolitis, which may be helpful in the initial assessment of these children.
We evaluated a variety of environmental and host factors that may contribute to the severity of RSV bronchiolitis in the RSV Bronchiolitis in Early Life prospective cohort study. Severity of bronchiolitis was based on the quantization of lowest O(2) saturation and the length of stay. These factors included the child's and family's demographics, presence of household allergens (dust mite, cat, dog, and cockroach), peripheral blood eosinophil count, immunoglobulin E level, infant feeding, prior illnesses, exposure to intrauterine and postnatal cigarette smoke, and family history of atopy.
We prospectively enrolled 206 hospitalized infants, all under 12 months old (4.0 +/- 3.3 months old), with their first episode of severe RSV bronchiolitis (mean O(2) saturation: 91.6 +/- 7.3%; length of stay: 2.5 +/- 2.5 days; presence of radiographic opacities: 75%). Patients were excluded for a variety of reasons including previous wheezing, regular use of bronchodilator or antiinflammatory medications, any preexisting lung disease including asthma, chronic lung disease of prematurity/bronchopulmonary dysplasia, or cystic fibrosis; gastroesophageal reflux disease on medical therapy; or congenital anomalies of the chest or lung.
Age was found to be a significant factor in the severity of infection. The younger an infant was, the more severe the infection tended to be as measured by the lowest oxygen (O(2)) saturation. We also found that infants exposed to postnatal cigarette smoke from the mother had a lower O(2) saturation than those not exposed. However, there was no significant difference in RSV bronchiolitis severity between infants exposed only to intrauterine smoke and those infants never exposed to cigarette smoke. Infants with a family history of atopy, especially a maternal history of asthma or hay fever, had a higher O(2) saturation. Although a history of maternal atopy seemed to be protective, there was no association between allergens and bronchiolitis severity, although 25% of households had elevated allergen levels. Black infants demonstrated less severe RSV bronchiolitis than their white counterparts. Multivariate analysis revealed age, race, maternal atopy, and smoking to be associated with severity of RSV bronchiolitis.
The severity of RSV bronchiolitis early in life seems modified by postnatal maternal cigarette smoke exposure and atopy and age of the infant, not by levels of allergens in the home environment.
呼吸道合胞病毒（RSV）细支气管炎是儿童住院的常见原因，并且越来越多地被认为是哮喘发生的一个危险因素。关于决定RSV细支气管炎严重程度的因素知之甚少，而这可能有助于对这些儿童进行初始评估。
在“生命早期RSV细支气管炎”前瞻性队列研究中，我们评估了多种可能导致RSV细支气管炎严重程度的环境和宿主因素。细支气管炎的严重程度基于最低氧饱和度的量化和住院时间。这些因素包括儿童及其家庭的人口统计学特征、家庭过敏原（尘螨、猫、狗和蟑螂）的存在情况、外周血嗜酸性粒细胞计数、免疫球蛋白E水平、婴儿喂养方式、既往疾病、宫内和出生后接触香烟烟雾情况以及特应性家族史。
我们前瞻性纳入了206名住院婴儿，均未满12个月（平均年龄4.0±3.3个月），他们首次发作严重RSV细支气管炎（平均氧饱和度：91.6±7.3%；住院时间：2.5±2.5天；存在影像学模糊：75%）。因各种原因排除患者，包括既往喘息、定期使用支气管扩张剂或抗炎药物、任何既往存在的肺部疾病（包括哮喘、早产慢性肺部疾病/支气管肺发育不良或囊性纤维化）；接受药物治疗的胃食管反流病；或胸部或肺部先天性异常。
发现年龄是感染严重程度的一个重要因素。婴儿年龄越小，以最低氧（O₂）饱和度衡量的感染往往越严重。我们还发现，暴露于母亲产后香烟烟雾的婴儿氧饱和度低于未暴露的婴儿。然而，仅暴露于宫内烟雾的婴儿与从未暴露于香烟烟雾的婴儿在RSV细支气管炎严重程度上没有显著差异。有特应性家族史的婴儿，尤其是母亲有哮喘或花粉热病史的婴儿，氧饱和度较高。虽然母亲有特应性病史似乎具有保护作用，但过敏原与细支气管炎严重程度之间没有关联，尽管25%的家庭过敏原水平升高。黑人婴儿的RSV细支气管炎比白人婴儿轻。多因素分析显示年龄、种族、母亲特应性和吸烟与RSV细支气管炎严重程度相关。
生命早期RSV细支气管炎的严重程度似乎受到产后母亲接触香烟烟雾、特应性和婴儿年龄的影响，而非家庭环境中的过敏原水平。
