Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis in infants and was the cause of over 700,000 hospitalizations of young children from 1992 to 2009 or over 40,000 hospitalizations a year in the US. Each winter this disease causes many parents to come into the office with their infant breathing hard and fast, with a sticky mucous-like cough and what seems to be a wheeze (noisy exhale). When the illness gets bad they can no longer breast feed or take their formula and they eventually may need oxygen support which is when they typically end up in the hospital.
The study “Pneumococcal Disease in Infants: A Time Series Analysis of US Hospitalization Data,” (which you can read here… ) showed that among children under one year old, 20% of the pneumococcal pneumonia cases were associated with RSV, and for children 1-2 years old, 10% of the pneumococcal pneumonia cases were associated with RSV infection.
Pneumococcal pneumonia is both more dangerous than RSV alone, and treatable, so identifying it is important when a child under age 2 seems to have RSV bronchiolitis and possible pneumonia. Physicians tend to feel confident that they have identified the source of the problem when they have proven for example that a sick infant has RSV. We tend to attribute symptoms to one infection. This study should put doctors on alert that when you have an especially ill looking infant with bronchiolitis, consider the possibility of pneumococcal infection as well.
Working in my urgent care recently, on one weekend I had three very ill RSV positive infants with pneumonia clinically. I obtained a complete blood count (CBC) and in all three of these cases the white blood cell count (WBC) was over 25,000 with mostly neutrophils (a pattern we see with bacterial disease). Some physicians are aware that WBC counts that high are almost always caused by strep pneumococcus. All three of these infants were treated with antibiotics and hospitalization was prevented. Note that RSV is viral and antibiotics have no place in the treatment of viral illness.
This article is important since it provides significant evidence to support obtaining a CBC in the very ill bronchiolitis infant and when the WBC is sky high (over 20,000) consider treating for pneumococcal pneumonia and bacteremia.