Why does albuterol help in viral URI and not bronchiolitis?
When a child present with cold, cough, runny nose and wheezing, it could either be a viral URI or bronchiolitis. If the age of child is 2yrs or less it is most likely bronchiolitis. And in these children giving albuterol is not a good treatment.
In an older child with viral induced wheezing, the cause is most likely bronchospasm and inflammation of the airways which lead to narrowing. And the muscles develop receptors now that respond to albuterol treatment. Thus giving albuterol nebulization in these children help by relieving the spams and opening up airways.
In bronchiolitis, the cause of the symptoms is mostly a mucous plug. Even if albuterol work and open airways it will not remove the mucous plug and hence the mucous will move and clog some other part of the lung. The best treatment here is to give saline nasal spray and do nasal bulb suctioning.