Viral infections, especially Respiratory Syncytial Virus (RSV), induce inflammation in the lower respiratory tract, resulting in edema, necrosis of epithelial cells, bronchospasm, and increased mucus production in the bronchioles.
This inflammation heightens airway resistance, leading to air trapping, atelectasis, and hyperinflation. Additionally, nasal obstruction arises due to mucus production.
Clinical features of bronchiolitis
Common symptoms include rhinorrhea, tachypnea, wheezing, coughing, accessory muscle use, nasal flaring, and fever.
Wheezing and crackles are heard on chest examination.
These symptoms may last 7 to 21 days, peaking between days 3 and 5.
Note that, some infants may develop severe disease with apnea, leading to hypoxia and requiring endotracheal intubation.
Diagnosis of bronchiolitis
Clinical diagnosis is suspected by history of typical symptoms in chuldren under 2 years of age.
Though rapid viral antigen tests may be helpful, routine blood tests and routine radiographs are not necessary.
Monitoring oxygen saturation with pulse oximetry is important for severity assessment.
Treatment of bronchiolitis
Some important outpatient management include: Saline instillation into nares followed by suctioning, frequent small feeds, and hand hygiene.
Bronchodilators are not suggested for routine use. Bronchodilators may improve symptoms briefly but do not shorten the days of symptoms, admission rates or length of stay.
Inhaled epinephrine and corticosteroids may help when used in combination in severe cases. Hypertonic Saline has no proven benefits in routine use.
Oxygen should be given to keep SpO2 above 90%. Noninvasive ventilatory support may help avoid intubation and mechanical ventilation.
Disposition of bronchiolitis
Advise caregivers to promptly seek reevaluation if any of these symptoms emerge: respiratory distress signs such as tachypnea, observed retractions, and feeding difficulties.
Demonstrate correct nasal suctioning methods to caregivers. Indications for admission include: Prematurity, persistent tachypnea, dehydration, witnessed apnea, and oxygen desaturation with SpO2 below 90%.
Remember to educate parents about the potential persistence of symptoms for up to 3 weeks to prevent unnecessary returns to the emergency department due to persisting mild symptoms.
Take home message
Bronchiolitis is a common viral illness in infants, especially during winter months. It’s symptoms typically resolves on its own but can last for up to 3 weeks.
Treatment focuses on hydration and symptom management rather than the infection itself.
High risk infants include babies less than 2 months of age and infants born prematurely, who may experience recurrent apneic spells and may require hospital admission.
Palivizumab may prevent bronchiolitis caused by RSV in extremely vulnerable patients as suggested by the American Academy of Pediatrics.