Bronchiolitis is a common lower respiratory tract infection in infants and young 
children, and respiratory syncytial virus (RSV) is the most common cause of this 
infection. RSV is transmitted through contact with respiratory droplets either 
directly from an infected person or self-inoculation by contaminated secretions 
on surfaces. Patients with RSV bronchiolitis usually present with two to four 
days of upper respiratory tract symptoms such as fever, rhinorrhea, and 
congestion, followed by lower respiratory tract symptoms such as increasing 
cough, wheezing, and increased respiratory effort. In 2014, the American Academy 
of Pediatrics updated its clinical practice guideline for diagnosis and 
management of RSV bronchiolitis to minimize unnecessary diagnostic testing and 
interventions. Bronchiolitis remains a clinical diagnosis, and diagnostic 
testing is not routinely recommended. Treatment of RSV infection is mainly 
supportive, and modalities such as bronchodilators, epinephrine, 
corticosteroids, hypertonic saline, and antibiotics are generally not useful. 
Evidence supports using supplemental oxygen to maintain adequate oxygen 
saturation; however, continuous pulse oximetry is no longer required. The other 
mainstay of therapy is intravenous or nasogastric administration of fluids for 
infants who cannot maintain their hydration status with oral fluid intake. 
Educating parents on reducing the risk of infection is one of the most important 
things a physician can do to help prevent RSV infection, especially early in 
life. Children at risk of severe lower respiratory tract infection should 
receive immunoprophylaxis with palivizumab, a humanized monoclonal antibody, in 
up to five monthly doses. Prophylaxis guidelines are restricted to infants born 
before 29 weeks' gestation, infants with chronic lung disease of prematurity, 
and infants and children with hemodynamically significant heart disease.