• Bronchiolitis is the most common lower respiratory tract disease in infants, and RSV (Respiratory syncytial virus) bronchiolitis is the leading cause of hospitalization in infants.  It will infect 90% of children by 2 years of life.
• Bronchiolitis "season" in the US is typically December to March but it does occur year round. 
• Pathology is caused by respiratory epithelial cell death that results in inflammation, edema, smooth muscle contraction, bronchoconstriction and mechanical obstruction by cellular debris and mucus plugging.
• History that suggest Bronchiolitis is cough, rhinorrhea, fever
• Most common PE findings are runny nose, tachypnea, wheezing, cough, crackles, use of accessory muscles,  and/or nasal flaring.
• Respiratory distress, dehydration, sepsis, and RSV associated apnea are feared severe complications.
• RSV associated apnea may be the presenting symptom in some infants. 
  • Infants at greatest risk for this are younger (usually < 3 months), hx of prematurity, hx of apnea of prematurity, and those who are early on in the illness.

 

References

Bronchiolitis:Diagnosis and Treatment of an Increasingly Common Seasonal Presentation.  Pediatric Emergency Medicine Reports. Nov 2008. Volume 13, Number 11