What are the clinical causes, diagnosis, and treatment of bronchiolitis?

From the Guidelines

Bronchiolitis is a common lower respiratory tract infection in infants and young children, primarily caused by respiratory syncytial virus (RSV), and its diagnosis is clinical, based on symptoms including wheezing, cough, increased respiratory rate, chest retractions, nasal flaring, and crackles on auscultation, typically preceded by upper respiratory symptoms, as stated in the 2014 clinical practice guideline by the American Academy of Pediatrics 1. The clinical presentation of bronchiolitis can vary, but it is characterized by acute inflammation, edema, and necrosis of epithelial cells lining small airways, increased mucus production, and bronchospasm, as described in the 2006 study on the diagnosis and management of bronchiolitis 1. Some key points to consider in the diagnosis and management of bronchiolitis include:

• The use of radiographic or laboratory studies is not recommended routinely, as stated in the 2014 clinical practice guideline 1.
• Treatment is largely supportive, focusing on maintaining hydration and oxygenation, with nasal suctioning helping to clear secretions, and supplemental oxygen provided if oxygen saturation falls below 90-92% 1.
• Bronchodilators like albuterol are not routinely recommended due to limited benefit, as shown in studies such as the one by Chavasse et al 1.
• Corticosteroids, antibiotics, and nebulized hypertonic saline are generally not indicated unless there are specific complications, as stated in the 2014 clinical practice guideline 1.
• Most cases can be managed at home with careful monitoring for respiratory distress, adequate fluid intake, and nasal suctioning, but hospital admission is necessary for infants with severe respiratory distress, oxygen requirement, dehydration, or those under 3 months with fever, as recommended in the 2014 clinical practice guideline 1.
• Prevention strategies include handwashing, avoiding exposure to sick contacts, and for high-risk infants (premature, with chronic lung or heart disease), palivizumab prophylaxis may be considered during RSV season, as stated in the 2014 clinical practice guideline 1.

From the FDA Drug Label

FULL PRESCRIBING INFORMATION 1 INDICATIONS AND USAGE Synagis is indicated for the prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in pediatric patients: Limitations of Use: The safety and efficacy of Synagis have not been established for treatment of RSV disease

The clinical cause of bronchiolitis is not directly addressed in the label, but it mentions that Synagis is used to prevent serious lower respiratory tract disease caused by respiratory syncytial virus (RSV). The diagnosis of bronchiolitis is not mentioned in the label. The treatment of bronchiolitis is not established for Synagis, as stated in the Limitations of Use section 2.

From the Research

Clinical Cause of Bronchiolitis

• Bronchiolitis is an acute small airways inflammation mainly caused by a viral infection, with respiratory syncytial virus being the most common virus associated with the disease 3.
• It is a leading cause of acute illness and hospitalization for infants and young children worldwide 4.

Diagnosis of Bronchiolitis

• The diagnosis of bronchiolitis is typically based on clinical presentation, with no specific test available to confirm the diagnosis.
• Management of bronchiolitis can be facilitated by recognizing the risks and benefits of various therapies, understanding the markers of disease severity, and gaining familiarity with the time course of viral replication compared to presentation of symptoms 5.

Treatment of Bronchiolitis

• The mainstay of therapy for bronchiolitis is supportive care, including assisted feeding and hydration, minimal handling, nasal suctioning, and oxygen therapy 4, 3.
• Supplemental oxygen should be used to maintain oxyhemoglobin concentrations ≥90% 6.
• High-flow nasal cannula may reduce intubation rate, but its effect on length of stay is unclear 6.
• Nebulized hypertonic saline may provide some benefit for patients with anticipated prolonged length of stay, but is not routinely recommended 6.
• Pharmacological interventions, including nebulized bronchodilators, steroids, and antibiotics, generally have limited or no evidence of efficacy and are not advised by National Institute of Health and Care Excellence 3.
• The use of systemic corticosteroids has been proposed for bronchiolitis, but its efficacy is still controversial and most studies suggest it has no benefit for the treatment of bronchiolitis, even for patients with mechanical ventilation 7.