Differential Diagnosis for Mild Bronchiolitis with Hyperinflation

• Single most likely diagnosis
  • Respiratory Syncytial Virus (RSV) infection: This is the most common cause of bronchiolitis, especially in infants and young children, leading to hyperinflation due to airway obstruction.
• Other Likely diagnoses
  • Influenza: Can cause similar symptoms, including bronchiolitis and hyperinflation, especially during flu season.
  • Human Metapneumovirus (HMPV): Another common viral cause of bronchiolitis, presenting with symptoms similar to RSV.
  • Adenovirus: Can cause respiratory infections, including bronchiolitis, though less commonly than RSV.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Bacterial pneumonia: Although less common than viral causes, bacterial pneumonia can present with similar symptoms and requires prompt antibiotic treatment to prevent severe complications.
  • Pertussis (Whooping Cough): Especially in unvaccinated or under-vaccinated populations, pertussis can cause severe respiratory illness, including bronchiolitis and hyperinflation.
  • Congenital heart disease: Underlying heart conditions can exacerbate respiratory symptoms and lead to more severe outcomes if not recognized and managed appropriately.
• Rare diagnoses
  • Cystic Fibrosis: A genetic disorder that can lead to chronic respiratory infections and hyperinflation, though typically presents with other systemic symptoms.
  • Immunodeficiency: Conditions affecting the immune system can increase susceptibility to severe or atypical infections, presenting with bronchiolitis and hyperinflation.
  • Foreign body aspiration: Though more commonly associated with acute obstruction, chronic aspiration can lead to bronchiolitis-like symptoms and hyperinflation.