Cause:
Bronchiolitis is a common viral infection of the small airways (bronchioles). Respiratory Syncytial Virus (RSV) causes 80% of these infections. Others are due to other respiratory viruses. It is typically seen in babies under 12 months to 2 years old. It is like a ‘bad cold’ but happening lower down in the bronchioles where the mucosal lining is inflamed and produces lots of clear secretions. Since babies have narrow bronchioles, this inflammation can cause some trouble breathing.
Diagnosis:
Bronchiolitis follows a typical timeline. Days 1-2: blocked and snotty nose. Days 2-4: difficulty breathing, lots of coughing. Days 3-4: difficulty feeding, breathing, lots of coughing. Days 4-6: better but coughing persists. On auscultation, doctors hear secretions in the bronchioles (crackles) and wheeze as air passes through the bronchioles narrowed by the secretions. There are no investigations for bronchiolitis. It is a clinical diagnosis. A nasopharyngeal aspirate (NPA) taken by placing a very thin suction catheter up the nostril of the baby can identify the virus but this is purely informative and does not affect treatment.
Progress and treatment:
The vast majority of babies with bronchiolitis stay at home. They cough but feed well and have a normal behaviour. They recover completely in time. Often the cough is worse at night because they are lying down flat. It can then help if they sleep in a more upright position by lifting the mattress or sleep in a seat like a car seat for the night while the cough is at its worst. The main treatment is supporting the baby through this illness and it may be that they need smaller volumes of frequent feeds. Saline nasal drops can assist with nasal secretions and help before feeding. Chest physiotherapy has now been shown to be inefficient at helping babies unless they have a background of a lung or neuromuscular disorders. It is important to observe for concerning features as described below.
Babies at risk:
Some babies who have bronchiolitis are more at risk and often need hospitalisation. These are babies who are either premature (less than 34 weeks) or who are less than 3 months old, who have a pre-existing lung disorder or heart disease or who have a neuromuscular disorder or a deficit in their immune system. Normal babies under the age of 6 weeks with bronchiolitis can sometimes have apnoeas, episodes where they stop breathing unless they are stimulated.
Complications:
50% continue to cough for 2 weeks and 90% stop coughing by 3 weeks. Rarely a secondary bacterial pneumonia occurs. And equally rarely, some babies wheeze for many months (Post Bronchiolitis Syndrome).
When to worry:
The following rarely happens but there is comfort in knowing what to look out for:
If baby does not feed properly because of breathing difficulties: if despite giving smaller volumes more frequently, less than half the normal amounts of fluids in a day is given or if the baby is having less than 2 wet nappies per day.
A temperature above 38.5°C may mean there is another infection.
If breathing is more difficult and chest movements while breathing change: more rapid, rib-cage very visible at each breath, extra muscles to breath are used, the middle of the chest or the muscles below the rib-cage are drawn-in or the muscles in the neck are more prominent.
If baby’s lips or tongue go blue/grey.
If baby stops breathing for a short period of time (even if only just over 20 seconds).
If baby is very lethargic and not responding normally.
Remember always contact your doctor if you are worried, even if simply for reassurance.