• Viral infection in children 0-2 years of age (but most commonly < 1yo)
  • Inflammation of the bronchioles, neutrophilic response
  • Infection of bronchiolar and cilia cells leads to mucous secretions, cell death, sloughing, and submucosal oedema. Distal airway obstruction occurs due to these changes and leads to air trapping (Meates-Dennis, 2005)
  • Infants have smaller calibre airways with a smaller surface area for gas exchange, making them more prone to severe airflow limitation and gas trapping when affected by an inflammatory response.
  • Commonly caused by RSV / Rhinovirus / Adenovirus

The history of presentation will usually be a few days of cough / coryza and reduced feeding with some increased work of breathing. There may or may not be fever.


  • What day of illness are we? Bronchiolitis tends to peak in severity at day 3-5. The cough can persist for several weeks.
  • How much are they feeding and how many wet nappies / day.
  • Anyone unwell at home.
  • Neonatal history, ex prem?
  • Any PMH of recurrent infections?
  • Any FH of breathing or heart problems?
  • Immunisations up to date?
  • Ask about risk factors for severe disease: Preterm, neuromuscular disease, congenital heart anomaly, chronic lung disease, chromosomal anomaly / syndrome, e.g. T21, immunodeficiency

Babies are obligate nasal breathers so when they are congested they find it hard to feed and breathe at the same time and may get tired quickly when feeding.


Widespread crackles and wheeze, increased work of breathing, cough.

Signs of increased work of breathing: SC / IC recession, sternal recession, head bobbing, tracheal tug, grunting, nasal flaring

Differentials: whooping cough, croup, viral induced wheeze, inhaled foreign body, cardiac problems


  • A viral NPA of course to identify which horrible winter virus(es) has caused this illness.
  • If moderate- severe increased work of breathing consider a capillary blood gas (if you can’t do these ask a PED nurse but also ask them to teach you because a cap gas is minimally invasive and can give you so much information)
  • A CXR is only really indicated if the baby is needing support such as highflow or if they have been in hospital for a few days and aren’t improving as expected with a prolonged oxygen requirement etc. CXR will show changes in viral and bacterial LRTI and will often just confuse you so before you request one think: What am I looking for on this CXR and how will it influence my management plan? If you find seniors requesting x-rays and you don’t know why you should feel confident to ask them why, because A) it could help them to re-consider and spare the child radiation exposure, or B) there could be a very good reason and you might learn something.


Management is supportive! Manage A-E

A If severely unwell (RSV, adenovirus and influenza can cause particularly nasty bronchiolitis, especially in vulnerable babies such as ex preterms) support with adjuncts or intubation

B Give supplemental oxygen. If > 6 weeks of age aim for sats of 90% and above and if < 6 weeks of age aim for sats > 92% (make sure to iterate this to nursing staff as junior nurses may often be aiming for sats of > 95% meaning oxygen is not being weaned as quickly as it can be.) If blood gases show a respiratory acidosis or WoB is severely increased you can consider highflow oxygen or CPAP.

C If they’ve been off feeds whilst unwell they may be dehydrated and need help with fluids / feeding. If signs of haemodynamic instability and dehydration then an IV cannula and fluid boluses in alliquots of 10ml/kg should be used.

If they are haemodynamically stable but not feeding well then an NG should be inserted to give feeds at 80-100ml/kg/day either continuously or 2-3 hourly depending on the work of breathing. If there is significant respiratory distress continuous NGT feeds are preferable as it means the stomach isn’t being filled with large amounts of feed that can compress on the lungs and cause further distress.

NG feeding is preferable to oral feeds if work of breathing is increase as: the baby may be tired and not feeding well, or not interested in feeding and  the baby will get more tired and have worsening of respiratory distress whilst trying to feed orally.

D Are they distressed or in pain?  Antibiotics aren’t indicated unless there are signs of a superadded infection e.g. high temperatures, not improving after day 5-7 with increasing oxygen requirement

Salbutamol nebulisers don’t work and aren’t indicated. There is a grey area here: if the baby is closer to or older than 1 year of age, there is a significant family history of atopy and there is majority wheeze rather than crackles and wheeze, it would be reasonable to trial a salbutamol nebuliser, but I would ask a senior for advice here.

Some people use Atrovent nebulisers but there is no evidence for their efficaciousness and NICE advise against using these.

Saline nasal drops can help clear some secretions and make feeding easier.

Reasons for admission

  • Oxygen requirement
  • Moderate to severe increased WoB / tachypneoa
  • Feeding < 50% of normal
  • Apnoea
  • If there are risk factors for increased severity of disease admit for observation

NICE Guidance

  • If < 6 weeks old aim for sats of 92% and above, if > 6 weeks old aim for sats or 90% and above
  • Give fluids by NG or OG tubes if they cannot take enough by mouth, only consider IV fluids if this is not tolerated or the baby has impending respiratory failure
  • Do not routinely carry out blood gases but do perform blood gases when there is impending respiratory failure or significant respiratory distress with oxygen requirement > 50%
  • Consider CPAP in impending respiratory failure
  • Do not use antibiotics, hypertonic saline, salbutamol, Atrovent, adrenaline, montelukast, systemic or inhaled corticosteroids
  • Discharge when clinically stable, taking adequate amounts of oral feed, maintaining acceptable sats for 4 hours including a period of sleep (NICE, 2021)

Safety net advice to give to parents if discharging home:

  • Look out for signs of increased work of breathing and bring back if any change of colour around lips and mouth or very breathless
  • bring back if tired and not feeding or if feeding < 50% of normal.
  • Offer smaller feeds more often as filling the stomach with a large feed can compress the chest and also can tire the baby if feeding for a prolonged period of time.

Evidence Base

High flow nasal cannula (HFNC) oxygen – AKA Airvo or optiflow

  • Provides warmed, humidified oxygen-air mixture at high flow via nasal cannulae. High flow delivers gas at higher rates of flow than low flow oxygen and can be delivered at a rate of 2-3L/kg/min up to a maximum of 60 litre / minute. It is thought to have an effect through washout of the nasopharyngeal dead space, as well as reducing upper airway resistance and providing some positive pressure. (O’Brien S & Paediatric Research in Emergency Departments International Collaborative (PREDICT) Network, 2019)
  • HFNC is better tolerated than nCPAP although does not reduce length of hospital stay or reduce rates of intubation and ventilation. (Lin J, 2018)
  • A Cochrane review in 2014 found insufficient evidence to determine the effectiveness of HFNC compared to conventional management of bronchiolitis (low flow oxygen and CPAP). However no adverse events were associated with the use of HFNC02 and it is a feasible therapy which is well tolerated. (Beggs S, 2014)

NG feeds vs IV fluids

  • A randomised control trial in 2013 found that there was no difference in length of stay between babies with bronchiolitis who were NGT fed compared to those who received IV fluids, but NG tube insertion was more likely to be successful on the first attempt compared to cannulation. (Oakley E, 2013)
  • A Cochrane review in 2021 had very similar findings. They reviewed studies comparing NG feeds to IV fluids in babies with bronchiolitis. There was no difference in the time to discharge between these two methods of hydration or time to resuming full oral feeds. However, NGT insertion is better tolerated and more likely to be successful on first attempt compared to cannulation. (Gill PJ, 2021)

Written by Dr Rebecca Evans, ST3 Paediatrics

How useful was this post?

Click on a star to rate it!

Average rating 4.7 / 5. Vote count: 14

No votes so far! Be the first to rate this post.

As you found this post useful...

Follow us on social media!

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Related Posts

Applying to Paediatrics
On the one hand, you wear a Disney lanyard, with a pocket stuffed...
Hand foot mouth disease
Hand, Foot and Mouth Disease
Hand foot and mouth disease is a very common illness in children...
Describing Skin Lesions
Describing Skin Lesions
It is quite common for you to need to describe rashes for documentation...

2 thoughts on “Bronchiolitis”

Leave a Comment

Your email address will not be published. Required fields are marked *

Follow us



Trending Now

Doctor's Pay Calculator 2024
We’ve created a pay calculator to help you better understand your salary, how much tax you’ll...
Paracetamol Overdose
Paracetamol overdose is a common presentation in A&E and so you may often find yourself looking after...
Understanding the MSRA
The Multiple Specialty Recruitment Assessment (MSRA) is a computer-based exam increasingly being used...
How to take a psychiatric history
Psychiatry, as a specialty is unique in that diagnostic methods, rely very heavily on symptomatology,...
Common Viral Infections (exanthem) in Paediatrics
Viral infections are extremely common in paediatrics and a common presentation to paediatric A&E...
Essential Apps
Here’s a list of apps that are in order of how essential we find them. There’s probably more...
Abdominal X-rays
The advantages of AXRs are far less radiation to patients & that they’re logistically easy...

Sign up for our awesome resources

Join over 40,000 users who have signed up for our free weekly webinars, referral cheat sheet & other exclusive content!