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Key Features

Essentials of Diagnosis

  • Clinical syndrome characterized by one or more of the following findings:

    • Coughing

    • Tachypnea

    • Labored breathing

    • Hypoxia

  • Irritability, poor feeding, vomiting

  • Wheezing and crackles on chest auscultation

General Considerations

  • Most common serious acute respiratory illness in infants and young children

  • Between 1% and 3% of infants with bronchiolitis require hospitalization, especially during the winter months

  • Respiratory syncytial virus (RSV) is by far the most common viral cause

  • Parainfluenza, human metapneumovirus, influenza, and adenovirus, are less common causes during early infancy

Clinical Findings

  • Fever (1–2 days)

  • Rhinorrhea

  • Cough

  • Wheezing

  • Tachypnea

  • Respiratory distress

  • Breathing pattern is shallow, with rapid respirations


Laboratory Findings

  • Nasal wash

    • Can be used to identify the causative pathogen

    • Not necessary to make the diagnosis

  • Peripheral white blood cell count may be normal or show a mild lymphocytosis


  • Chest radiographs are not indicated in children who

    • Have bilateral, symmetrical findings on examination

    • Are not in significant respiratory distress

    • Do not have elevated temperature

  • Chest radiographic findings are generally nonspecific and typically include

    • Hyperinflation

    • Peribronchial cuffing

    • Increased interstitial markings

    • Subsegmental atelectasis


  • Mst children are treated as outpatients

  • However, hospitalization is required in infected children with

    • Hypoxemia on room air

    • History of apnea

    • Moderate tachypnea with feeding difficulties

    • Marked respiratory distress with retractions

  • Supportive strategies used during hospitalization

    • Frequent suctioning

    • Administration of adequate fluids to maintain hydration

  • Supplemental oxygen should be administered if hypoxemia is present

  • Antibiotics not necessary unless there is evidence of an associated bacterial pneumonia

  • Bronchodilators and corticosteroids

    • Have not been shown to change the severity or the length of the illness

    • Not recommended

  • High-risk patients with RSV bronchiolitis may need to be hospitalized and treated with ribavirin



  • The most effective preventions against RSV infection are proper handwashing techniques and reducing exposure to potential environmental risk factors.

  • Prophylaxis with a monoclonal antibody (palivizumab) is effective in reducing the rate of hospitalization and associated morbidity in high-risk premature infants and those with chronic cardiopulmonary conditions.

  • Patients at risk for life-threatening RSV infections should receive prophylactic therapy

    • Children younger than 24 months whose gestational age is < 35 weeks

    • Children younger than 24 months with other severe pulmonary conditions, congenital heart disease, neuromuscular disease, or significant immunocompromise


  • Bacterial superinfection is a rare complication of viral pneumonia

  • Bronchiolitis due to RSV infection contributes substantially to morbidity and mortality in children with underlying medical disorders


  • Very good for most infants

  • Mortality rate has decreased substantially due to improved supportive care and prophylaxis with palivizumab


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