Bronchiolitis: Clinical sciences

Bronchiolitis refers to a viral infection of the lower respiratory tract that primarily affects the bronchioles, and causes airway inflammation and obstruction. This is most often caused by respiratory syncytial virus, or RSV for short, but can also be caused by other viruses, including human metapneumovirus and parainfluenza. Bronchiolitis primarily affects children under 2 years of age, most often during fall and winter months, and it’s typically mild and self-limited, but infants with certain risk factors can develop severe respiratory distress. As far as the treatment goes, bronchiolitis can be managed in the outpatient or hospital setting.

If your patient presents with a chief concern suggesting bronchiolitis, first perform an ABCDE assessment to determine if your patient is unstable or stable. If unstable, stabilize their airway, breathing, and circulation. Additionally, obtain IV access and put your patient on continuous vital sign monitoring, including respiratory rate, pulse oximetry, and cardiac monitoring. Finally, if needed, don’t forget to provide supplemental oxygen.

Now, let’s go back to the ABCDE assessment and take a look at stable patients. In this case, you should first obtain a focused history and physical exam. Your patient is likely to be under 2 years of age; with a history of illness that started with milder symptoms, such as fever and rhinorrhea for the first three days, followed by worsening of symptoms like respiratory distress. It’s important to note that a young infant under 2 months of age could present with apnea as their first sign, in the absence of any other symptoms!

Physical exam typically reveals labored breathing, tachypnea, and hypoxia. You may detect nasal flaring or grunting, as well as abdominal breathing or suprasternal, intercostal, and subcostal retractions; while auscultatory findings may include wheezing, crackles, and a prolonged expiratory phase. Infants with poor oral intake may have signs of dehydration, like a sunken fontanelle and poor skin turgor. The presence of these findings should make you suspect bronchiolitis, which is usually a clinical diagnosis based on the presence of classic history and physical exam findings.