From the Guidelines
Bronchiolitis typically occurs in infants and young children under 2 years of age, with the peak incidence occurring between 3 and 6 months of age. The vast majority of cases (about 90%) occur in children younger than 12 months old 1. This respiratory infection is most commonly caused by the respiratory syncytial virus (RSV), though other viruses like rhinovirus, adenovirus, and influenza can also cause it. Bronchiolitis is particularly common during winter and early spring months when these viruses circulate more widely. The age distribution is related to several factors, including the small airway size in infants which makes them more susceptible to obstruction from inflammation and mucus, their developing immune systems which haven't yet built immunity to common respiratory viruses, and their exposure to these viruses for the first time. After age 2, children typically develop larger airways and stronger immune responses, making bronchiolitis less common, though it can occasionally occur in older children and adults with compromised immune systems.
Some key points to consider when diagnosing and managing bronchiolitis include:
- The goal of diagnosis is to differentiate infants with probable viral bronchiolitis from those with other disorders 1
- Clinical signs and symptoms of bronchiolitis consist of rhinorrhea, cough, tachypnea, wheezing, rales, and increased respiratory effort manifested as grunting, nasal flaring, and intercostal and/or subcostal retractions 1
- The course of bronchiolitis is variable and dynamic, ranging from transient events, such as apnea, to progressive respiratory distress from lower airway obstruction 1
- Routine virologic testing is not recommended, except in certain situations, such as when an infant receiving monthly prophylaxis is hospitalized with bronchiolitis 1
It's also important to note that the management of bronchiolitis is primarily supportive, and antibiotics are not recommended for routine use in acute bronchiolitis 1. The use of bronchodilators, such as β-agonists, is also not recommended for routine use in bronchiolitis, as the evidence does not support their effectiveness in this population 1.
Overall, the diagnosis and management of bronchiolitis should be guided by the most recent and highest-quality evidence, with a focus on supportive care and avoiding unnecessary interventions.
From the Research
Age of Occurrence
Bronchiolitis typically occurs in children under the age of two, with the most common age range being between three and six months old 2.
Peak Incidence
The peak incidence of bronchiolitis is usually seen in the winter season, with a significant number of cases requiring hospitalization 2, 3.
High-Risk Age Group
Children under three months old are at the highest risk for severe bronchiolitis, with a higher likelihood of requiring oxygen support and having a longer hospital stay 3.
Key Characteristics
Some key characteristics of bronchiolitis in children include:
- Upper respiratory prodrome lasting one to three days before developing a persistent cough 2
- Fever and reduced feeding are common symptoms 2
- Very young infants may present with apnoeic episodes 2
- Symptoms normally peak between days three to five of the illness 2
- Evidence of increased work of breathing, such as tachypnoea, in drawing/recession, head bobbing, grunting, nasal flaring, or tracheal tug 2
Management and Treatment
Bronchiolitis is usually managed with supportive care at home, with hospital admission required for severe cases or high-risk groups 4. The effectiveness of various therapies, such as bronchodilators and corticosteroids, is still a topic of debate, with little consensus on optimal management strategies 5.