### What you need to know Bronchiolitis is a viral lower respiratory tract infection occurring mainly in the winter months, most commonly caused by respiratory syncytial virus (RSV). It is seen primarily in infancy but occurs up to 2 years of age and is the most common indication for hospitalisation in this age group. Ninety percent of children are infected with RSV in their first 2 years, and up to 40% will experience bronchiolitis during the initial infection.1 Bronchiolitis usually begins with a viral upper respiratory tract prodrome (rhinorrhoea and cough) followed by increasing respiratory effort (tachypnoea and/or accessory muscle use) with wheezing and/or crackles heard on chest auscultation. Diagnosis and assessment of disease severity is based on history and physical examination findings and does not require any confirmatory testing (box 1).1 Box 1 ### Guidance on optimal assessment of infants with bronchiolitis12RETURN TO TEXT

中文翻译：

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避免对患有典型细支气管炎的婴儿进行胸部 X 线检查

### 您需要知道的 细支气管炎是一种病毒性下呼吸道感染，主要发生在冬季，最常见的是由呼吸道合胞病毒 (RSV) 引起。它主要见于婴儿期，但可发生至 2 岁，是该年龄组最常见的住院指征。90% 的儿童在头两年感染 RSV，多达 40% 的儿童在最初感染期间会出现细支气管炎。 1 细支气管炎通常始于病毒性上呼吸道前驱症状（流鼻涕和咳嗽），然后是呼吸用力增加（呼吸急促）和/或辅助肌肉使用）在胸部听诊时听到喘息和/或噼啪声。