Why Is My Baby Coughing So Much?

December 5, 2011

Body

As the calendar turns from November to December, frost and the sounds of the holidays fill the air. However, each year brings a common pathogen, respiratory syncytial virus, better known as RSV. Last fall, I wrote about RSV in conjunction with the flu and respiratory illness; this season seems to be very active so far, resulting in mild to severe disease in scores of small children in the clinics, emergency rooms and hospital floors.

Understanding RSV begins with understanding what this acronym means in medical terminology. Every parent understands the R and V of RSV. Respiratory means that it penetrates the breathing system, somewhere from the nose to the lungs. Additionally, it is a winter virus, not a bacteria, making it extremely contagious, residing in the mucous and droplets coughed or sneezed from adults and children alike this time of year. Syncytial can be broken down into it Greek roots, "syn" and "cyt". The root "syn" means bringing together, as in synergy, and "cyt" means cells. This virus, like a common cold virus or the flu, invades our respiratory tract; however, RSV attacks the linings of small airways connecting the bigger airways delivering oxygen to our lungs. Imagining these small airways, called bronchioles, as straws helps this analogy. The virus causes shedding of the cells that line the bronchioles and causes them to clump inside the airways, essentially blocking them like ice chips in a poorly made frozen drink. The bigger the clumps or smaller the straw, the more blockage and reduced area for passage from one end to another. This explanation partly explains why RSV may cause minimal disease in the older child or adult, yet cause a frequent cough or wheeze as air struggles through the very small bronchioles of a baby.

Infants and toddlers under two years of age are most commonly brought to our attention for symptoms like fever, runny nose "like a faucet", coughing that results in vomiting, and spasms of cough keeping a child up at night. Many of these patients are helped by simple remedies or medicines if indicated, and the disease lasts for about one week from start to finish. However, RSV can result in moderate to severe disease, causing hospitalization of previously healthy and predisposed children. Youngsters born premature (less than 32 weeks), those who are immunocompromised or with chronic lung disease and/or significant congenital heart disease, stand a greater chance of developing progressive complications from the infection.

A quick non-invasive test of the baby's nasal discharge can be screened for RSV and a measurement of the oxygen level can be determined at your doctor's office. If the basic recommendations I made in last winter's post (saline/suctioning as well as ever reducers) do not improve a young child's breathing or coughing, you notice color change (blue/purple) in the lips or face of a child, or you feel that the breathing is too fast for an infant  (>60 breaths per minute) or young toddler (>50 bpm) to safely drink without coughing/choking, please notify your pediatrician to get the appropriate care the child needs.

These images may help illustrate RSV for you:

 

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