Q: My daughter tells me that her son was diagnosed … with bronchitis.
He was working really hard to breathe, and went home from the emergency room with oxygen but no other medicines.
I thought bronchitis was a disease of old people and smokers. How did my 11-month-old grandson get it?
A: I think your daughter probably misunderstood what the ER doctor said, or perhaps she or he was unclear.
You’re right, even babies exposed to second-hand smoke almost never get bronchitis. What babies get, whether their parents smoke or not, is bronchiolitis, a very common condition at this time of year, caused by a virus.
The difference is this: the bronchi are the large air passages that extend down from the trachea into the lungs; the bronchioles are much smaller, branching off the bronchi like twigs in an upside-down-tree like arrangement, with the “leaves” being represented by the alveoli, where gases vital to life are exchanged. Bronchiolitis is a viral infection of these “twigs,” mostly in babies and toddlers; bronchitis, a viral or bacterial infection that affects the upper airway in older people and smokers.
1 to 3 of every 100 American infants is hospitalized due to bronchiolitis before the age of 2, so your grandson is fortunate not to have gotten sufficiently severe disease to cause a hospital stay. That he was sent home with oxygen, though, indicates that the treating physician found that his blood oxygen level was low enough to be worrisome, and I’m sure he was coughing and wheezing, struggling for breath.
I am certain that that doctor also told your daughter of signs to watch for – signs that the unpredictable disease was getting worse, with instructions to return to the emergency room if that happened.
You mentioned that the baby was given no medications other than oxygen. That surprises many people; it would have surprised physicians who cared for bronchiolitis patients twenty years ago. Bronchiolitis at that time was often treated in much the same way we would treat a patient with asthma – medications to “open up” the constricted airways, a bronchodilator like albuterol, and other medications to decrease the immune system’s attacks on the airways, steroids like prednisone.
Bronchiolitis is similar to asthma in some respects, so it makes sense to think they might be treated similarly, and we once used large amounts of both albuterol and prednisone in this condition.
The problem is, these medicines don’t work in most bronchiolitis patients. Instead of an immune system being the attacking agent, it’s a virus, and there’s no evidence that either bronchodilators or steroids improve the outcome.
Antibiotics don’t work for bronchiolitis either, as it’s a viral disease. We do have some antiviral medications these days – oseltamivir for influenza, acyclovir for herpes infections, zidovudine for human immunodeficiency virus (HIV) infections among them. No such antivirals are available for the main culprit in bronchiolitis, the respiratory syncytial virus (RSV), or its less common sidekick, the human metapneumovirus (HMPV).
And we have neither immunizations to prevent RSV or HMPV infections nor any medication that will treat them once they are contracted. We have to wait for the body to shed the infection.
Even if the child were hospitalized, we would only be able to provide “supportive care” while the body kicked the infection: IV fluid if needed, suction of nose secretions and oxygen.
Respiratory syncytial virus is interesting from many standpoints. First its name: “respiratory” refers to its main effect, which is upon the breathing apparatus, which reaches from the nose and mouth to the lung tissue.
“Syncytial” refers to its ability, like the “Merge Cells” command in my word processor program, to dissolve the walls separating one respiratory tract cell from another, creating a not-very-functional mega-cell with lots of nuclei.
Secondly, attempts to develop a vaccine against this scourge, which causes some 400,000 hospitalizations and 400 deaths in the US every year, have been quite unsuccessful so far.
Thirdly, it isn’t clear whether the body’s immune system protects against the virus and its effects or actually makes the virus’s depredations worse.
Probably most important, it is unknown to what extent RSV infection (or HMPV, for that matter) contributes to the rising incidence of asthma in children. It is clear that more children who have had bronchiolitis will end up having repeated wheezing and asthma than children who have never had the condition your grandchild has suffered.
Perhaps an early bronchiolitis history causes damage that leads to asthma. However, an alternative explanation might be that of children genetically or otherwise “programmed” toward asthma have a greater tendency to have a bronchiolitis-like picture when exposed to RSV and HMPV.
Despite the many uncertainties, 99.9% of infants who get bronchiolitis recover from it.
And a vaccine against RSV will probably be as successful against this very unpleasant disease as vaccines have been against measles or polio or smallpox. It’ll be tested and approved too late to protect your grandson; I assume by now he’s feeling much better, though probably still coughing for another week or two.
Lance Chilton, M.D., is a pediatrician at the Young Children’s Health Center in Albuquerque, associated with the University of New Mexico. Send questions to email@example.com.