Original Editor - Jerome Ng

Top Contributors - Jerome Ng, Kim Jackson, Adam Vallely Farrell and Vidya Acharya

Clinically Relevant Anatomy

Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs, in which air passes through the nose or mouth to the alveoli of the lungs where gas exchange takes place.
Lung anatomy.jpg

Mechanism of Injury / Pathological Process

Bronchiolitis typically occurs with primary infection or reinfection with a viral pathogen, but occasionally is caused by bacteria (eg, Mycoplasma pneumoniae). In young children, the clinical syndrome of bronchiolitis may overlap with recurrent virus-induced wheezing and acute viral-triggered asthma.

Clinical Presentation

Bronchiolitis is a major cause of illness and hospitalization in infants and children younger than two years. Symptoms include:

  • Persistently increased respiratory effort (tachypnea, nasal flaring, intercostal or suprasternal retractions, accessory muscle use, grunting)
  • Hypoxemia
  • Apnea
  • Acute respiratory failure

Management / Interventions

  • Hydration
  • Respiratory support
  • Nasal suctioning
  • Supplemental oxygen

The following are interventions that may be used, but not as a routine intervention:

  • Trial of inhaled bronchodilator
  • Nebulized hypertonic saline
  • Glucocorticoids
  • Chest physiotherapy

Key Evidence

In the Cochrane review titled "Chest physiotherapy for acute bronchiolitis in children younger than two years of age", it was concluded that none of the chest physiotheray techniques (vibrations, percussions, slow passive expiratory techniques or forced expiratory techniques) have demonstrated a reduction in the severity of disease. Hence, these tecniques cannot be used as standard clinical practice for hospitalised patients with severe bronchiolitis.[1]

A state-of-art review suggests avoiding repeated airway clearance in infants and children with acute pulmonary disease.[2]


  1. Roqué i Figuls M, Giné-Garriga M, Granados Rugeles C, Perrotta C, Vilaró J. Chest physiotherapy for acute bronchiolitis in paediatric patients between 0 and 24 months old. Cochrane Database of Systematic Reviews 2016, Issue 2. Art. No.: CD004873. DOI: 10.1002/14651858.CD004873.pub5.
  2. Morrow BM. Airway clearance therapy in acute paediatric respiratory illness: A state-of-the-art review. South African Journal of Physiotherapy. 2019 Jun 25;75(1):12.