Paediatrics: Bronchiolitis
Pathophysiology:
Bronchiolitis is inflammation of the bronchioles caused by viral infection. The most common causative organism is Respiratory Syncytial Virus (RSV) making up 60-80% of cases [1]. Others include; adenovirus, Rhinovirus, coronavirus…. Not just COVID 19, influenza virus, parainfluenza virus and Metapneumovirus.
There are 2 distinct stages of bronchiolitis development. The first stage affects the upper airway where the virus causes inflammation of the epithelium in the nasopharynx resulting in nasal congestion, rhinorrhoea and common cold type symptoms which can collectively be known as coryzal symptoms. The second stage sees the virus move down to the lower respiratory tract within 1-3 days off the start of the coryzal symptoms [2]. Inflammation then develops in the small airways the bronchioles, resulting in oedema of these smaller airways and marked increased secretion of mucous causing plugging and narrowing. This gives the characteristic findings of expiratory wheeze due to narrow airways and turbulent air flow and crackles of the mucous plugging as the airways reopen. This combination then decreases the concentration of oxygen within the alveoli and therefore the amount of oxygen that moves into the circulation resulting in hypoxemia. In order to combat this the child will need to breathe harder and faster to compensate which we see as tachypnoea, tachycardia and increased work of breathing. This increased respiratory effort often results in the child having difficulty feeding which can lead to dehydration and this in combination with increased work of breathing can in severe cases result in the child tiring, becoming lethargic and in the worst of cases result in decompensated respiratory failure.
Most cases however are self-limiting and do not become this severe and children will recover without treatment in seven to 10 days with full resolution of the cough normally in two to three weeks.
There are however a sub group of patients with comorbidities that need to be considered as a higher risk for requiring hospitalisation these include:
· Congenital lung disease
· Congenital heart disease
· Younger than three months of age
· Prematurity (under 32 weeks)
· Down syndrome
· Cystic fibrosis
· Immunocompromised
· Neuromuscular disease
History Taking:
It is good practice when assessing a paediatric patient to not immediately jump on them and start examining or taking obs….. I can see your ECA holding that sats probe ready to pounce….. but if the child looks well and your not immediately concerned that they are Big sick, hang back and let them get used to your presence. Start by taking a thorough history from the parent.
Features in the history suggestive of Bronchiolitis:
- 1-3 day coryzal prodrome (rhinorrhoea/ cold type symptoms)
- Development of cough which can be dry or wet sounding
- Low-grade fever, normally < 39°C (high-grade fever does not exclude bronchiolitis but should make the clinician consider other differentials e.g. pneumonia/ sepsis).
- Increased work of breathing:
o fast/ laboured breathing,
o Recessions
o Accessory muscle use,
o Nasal flaring
o Head bobbing
o Hearing an audible wheeze or their child grunting.
- Enquire about feeding/ fluid intake
o Enquire about normal volume of feeds vs current in the illness. We ideally like children to maintain above 50% of normal feeds as lower than this is a red flag that they may become dehydrated. This may be challenging to ascertain in those that are breast fed, but parents are usually good at estimating. Remember they may feed less volume but more often when unwell this is fine as long as total volume isn’t markedly reduced. Bottle feeds can be calculated, however its still probably similar to get a gauge from the parents, they will likely know.
o Ask about urine output and number of wet nappies within the last 12-24 hours. This is a good marker of a child is becoming dehydrated and may need admission. No wet nappy for 12 hours is worrying sign for deterioration.
- Rarely and more commonly only in younger babies parents may have witnessed an episode of apnoea as an isolated symptom with no other obvious symptom. Sometimes apnoea can occur in combination with the above symptom mentioned. Apnoeic episodes should be considered a red flag and warrant conveyance to hospital. [3] [4] [5] [6] [7]
Past Medical History
Screen for known medical conditions/ co-morbidities mentioned in the pathophysiology risk factors, that may require you to lower your threshold for admission.
It is good practice as part of all paediatric history taking to enquire about birth history including antenatal, perinatal and postpartum complications including abnormalities found on scans, complicated births, whether there was a normal vaginal, instrumented, induced or caesarean section delivery. Ask about any postpartum need for resuscitation or admission to SCBU / NICU.
- Drug History –
o Ask about current medications, the vast majority of children will not be on any, however rarely some children with other co-morbidities may be on medications.
o Enquire about childhood immunisations and if the child is up to date with these and their vaccination schedule.
o Ask about any allergies to medications or food/ feed intolerances e.g. CMPA. Cows milk protein allergy !
- Social / Family History –
o Enquire who the baby lives at home with including older/ younger siblings
This is a good juncture to ask about other members of the family and whether they have been unwell. It is common for older siblings who are nursery or school age to bring home viral illnesses, coughs and colds that then spread around the family. You will likely note a common theme across many history takes of older school aged siblings being unwell first when assessing a child with bronchiolitis.
o Ask about parental smoking as this has been shown to increase in the risk of developing chest infections including bronchiolitis in young children [8]. Take this opportunity to do good health promotion and advise about passive smoking, explain that even smoking outside has been shown to be detrimental and encourage parents to consider quitting.
o As part of a good social history for all paediatric patients you should enquire about home circumstances, including; who lives at home with the child and whether there is social services involvement. Other children in the house – what schools they go to. Who they live with! These are important things to note in case of safeguarding referrals. Its good practice to note this for all children you attend. Make this a good habit!
o History of familial Atopy (Excema, asthma, allergies)
Examination:
The patient requires a comprehensive assessment which can either follow an A-E approach, especially if the child looks very unwell, or a systems examination. Whichever approach you chose consideration should be paid towards:
Respiratory examination:
· Note and document evidence of increased work of breathing such as
Intercostal recessions
Supraclavicular, or sternal recessions
Substernal and Subcostal retractions / recession
Document these as mild, moderate or severe. Mild subcostal recessions are relatively commonplace and children will likely cope well even with these present. However severe recession and other types of recession are more worrying features suggestive of a marked increase work of breathing.
Other features we need to look for are:
Tracheal tug
Head bobbing
Nasal flaring
Thoracoabdominal asynchrony
Tachypnoea (common symptom, but excessive rates are worrisome)
· Low oxygen saturations - NICE guidelines discuss children older than 6 weeks with oxygen saturations of 90% or higher or under 6 weeks with 92% or higher as potentially suitable saturations for a child to be discharged home. ≥ 92% is probably a sensible approach to consider. This may seem very different to usual practice around oxygen saturations, but often children with saturations like this can be quite well, despite the figure, and children are often discharged from hospital with oxygen saturations of 92% as per NICE guidance. [3]
Its important to build this into the wider assessment and how the child presents as a whole!
· On auscultation there is likely to be a combination of diffuse and widespread wheeze and crackles or both, unlike in older children and adults crackles are rarely indicative of pneumonia and are more likely viral bronchiolitis. However your suspicion of pneumonia should be raised if the child is very unwell, has a high fever (over 39°C) and has an area of focal crackles or reduced air entry with overlying bronchial breath sounds.
· Cyanosis
· Apnoea's
The clinician should also exam for:
· signs of dehydration e.g. dry mucous membranes, a sunken anterior fontanelle in younger babies, poor skin turgor, prolonged capillary refill time (> 2 seconds), absence of tears when crying, Poor skin turgor, dry nappies (none in last 12 hours).
· Lethargy and irritability
· Poor tone
· Reduced conscious level
· Poor feeding
· Rash
· Fever
· Colour, peripheral warmth
· Heart sounds
· Femoral pulses.
· Brief abdominal examination
It is good practice to expose the child down to a nappy during an examination and check all skin surfaces, including removal of the nappy for a short period to conclude the examination.
The patient should also have a full set of vitals including;
· Respiratory rate
· Heart rate
· Oxygen saturations,
· Temperature - measured tympanically in those < 4weeks or in the axilla for over this age [6].
· Blood pressure and blood glucose measurements may be required in addition but only if clinically relevant. Patients who are not feeding normally, or have altered mental status for example.
An important note regarding oxygen saturation is that this must be measured with the correct age-appropriate oximeter probe in the correct location for the device e.g. a finger probe should not be applied to the ear and or adult probes not used on young children. NICE released a patient safety warning in 2018, advising clinicians of the dangers and possible false readings, including erroneous / falsely high Sp02 levels when using oximeter probes wrongly. Paramedics therefore should ensure their service provides the correct equipment for this paediatric age group and they apply correctly [9] [3] [4] [5] [6] [7]
Click the picture to go to the course
Some paramedics have limited teaching or experience in paediatric assessment. If you feel that you would like to develop your skills in paediatric assessment we highly recommend you undertake the following FREE online course designed for health care professionals/ doctors working with children who are non paediatric specialist practitioners. The course covers a systematic quick 3-minute toolkit approach that easily be applied to all paediatric patients and teaches you how to do each step. There is also then a series of conditions/ presentations including breathing difficulties that are taught through video examples of symptoms mentioned above such as recession, head bobbing and nasal flaring etc. It’s a very visual approach to learning and something I did in my student paramedic undergraduate training and still helps me now to this point of my career…. Plus if you complete it you get a cool little certificate and who doesn’t like one of those for that shiny CPD portfolio for when the HCPC audit comes a knocking. Anyway back to Bronchiolitis…..
Diagnosing Bronchiolitis and Differential Diagnosis:
Bronchiolitis is predominantly a clinical diagnosis. There needs to be a reasonable level of diagnostic certainty but not necessarily absolute certainty when diagnosing it. As discussed earlier an appropriately aged child with a hx of coryza prodrome followed by a persistent cough, increased work of breathing, wheeze/crackles or both on auscultation, a low grade fever (<39°C) and poor feeding is the most common presentation as per the history and examination sections. However, both should also enquire about the symptoms that may worry RE another differential: The differentials you should consider are…
· Pneumonia – very unwell looking child, high grade fever, focal crackles
· Viral Induced Wheeze – persistent wheeze with no cackles in a child most likely over 2+ with some overlap between ages 1-2. Recurrent wheezer with viral illness, rapid onset over hours as opposed to days with bronchiolitis. Family or patient history of atopy.
· Pertussis / Whooping Cough – characteristic hacking, relentless cough with inspiratory whoop, unvaccinated child.
· Croup – Characteristic seal bark cough, all upper airway symptoms, stridor
· GORD – chronic cough, poor weight gain, reflux symptoms, distress post eating.
· Foreign Body Aspiration – suspected from history or concern from parents, choking episode, unilateral or focal wheeze
· Congenital Heart Disease / Failure – Cyanosis, SOB, Hepatomegaly, Heart Murmurs, abnormal pulses, abnormalities found on birth or 6/52 NIPE.
Treatment/ Management (the DO's and DO NOTs):
So we have reached our diagnosis and suspect this to be a case of bronchiolitis. We will cover admit vs discharge after this section, however, if you a transporting and your patient needs treatment, its time to decide which treatments you should give…. Wheezy child that an easy one salbutamol nebulisers right……… wrong, think again…. Here are the Dos and DONTs of treatment options for the child with bronchiolitis [10]
A systematic review of literature conducted by O’brien et al in 2018 [11] reviewed the literature surrounding proposed treatments for bronchiolitis. Unfortunately the conclusions from this study show, with the exception of supportive treatments e.g. feeding/ hydration support and oxygenation/ ventilation support, there is very little that is effective. Their recommendation were adopted into the formation of the Bronchiolitis guidelines across Australia and NICE in their 2021 updated bronchiolitis guideline the same for UK practice. [3] [12]
In the treatment of bronchiolitis then, the only treatments that can be provided if needed are:
· oxygen therapy (if saturations <90-92%).
· Feeding support (encouraging oral if not taking, IV if shocked or very dehydrated or NG in hospital).
· Fluid Challenge
· Ventilatory support if required
Treatments that SHOULD NOT be used are:
· Salbutamol nebulisers
· Ipratropium nebulisers
· Nebulised adrenaline
· Nebulised saline (outside of an RCT setting)
· Corticosteroids
· Antibiotics
Why do we not use Salbutamol even if there is a wheeze you ask?
Salbutamol is beta agonist and effective in the treatment of bronchoconstriction causing wheeze in the larger airways and a treatment commonly given by paramedics for asthma. However, the above mentioned systematic review of literature conducted by O'brien et al, and used as part of the guideline formation for Bronchiolitis, showed high-quality evidence that there is no clinical benefit from using salbutamol in bronchiolitis and there may even be a small amount of unwanted effects. [11]
Salbutamol’s lack of benefit has commonly been attributed to children under 1 not having the same amount of functional beta adrenoreceptors in the lungs that older children and adults have, hence salbutamol not working. However, more recent evidence is mounting that is indicating this to be incorrect and young children infact do have functioning beta receptors. The primary reason why salbutamol has limited effect in children with bronchiolitis is likely due to the pathology of bronchiolitis in that the wheeze is caused by turbulent air flow from mucous build up and oedema of the lower airways, as opposed to smooth muscle bronchoconstriction of the larger airways seen in other respiratory disease [13], [14]
The challenge comes when we consider the slightly older child 1-2 years who may have pathogenesis more in keeping with viral-induced wheeze (VIW) presentation. Here Salbutamol is an effective and mainstay component of treatment. There is no set age cut off where a child is more likely to present with bronchiolitis as opposed to viral-induced wheeze (VIW) and therefore some degree of clinical judgement is required. GP paeds tips have a good learning resource on this, that we would encourage people to check out.
In general, Bronchiolitis is a disease that develops gradually over days whereas VIW being in its nature bronchospasm, will come over a matter of hours. Both however have similar overlapping features and it is not unreasonable that in the child over 1 year of age, if VIW is suspected, considering a trial of Salbutamol with a review pre and post nebuliser/ burst therapy, examining for improvement.
In short, with Bronchiolitis the bottom line is Salbutamol shows no evidenced benefit.
When to Admit vs When to Discharge
Paramedics as health care professionals need to find a responsible and safe balance between admitting every child inappropriately and discharging a child home who is too unwell. In order to do this we need to formulate a safe discharge plan [15] To do this we need to know which children require admission, which we can safely discharge autonomously and which we maybe need to seek some advice over, as after all shared decision making is always a good thing and supports defensible practice. Here are some of the red flags that mean we should transport and admit a patient to hospital:
· Apnoea (observed or reported)
· Child looks seriously unwell to you as the health care professional
· Severe respiratory distress for example grunting, marked chest recession
· RR > 60/ min
· Cyanosis
· Poor feeding (50% or less than normal feeds, dry nappies or signs of dehydration) ]
· Oxygen saturations less <92% in air.
· Reduced conscious level or severe lethargy and tiring.
Consider hospital admission in those with:
· Risk factors identified in the pathophysiology section.
· We know from the pathophysiology section that Bronchiolitis normally presents with a disease development and worsening period over 3-5 days, before plateauing out and improving. Therefore when considering admission think about where the child is in the course of their illness. A child with borderline admission symptoms on day 2 should worry us far more than one with the same symptoms on day 5-6, as we know the former is likely to deteriorate further where as the latter is probably going to be on the improving slope of the journey.
· Concern about the parent’s ability to cope, many parents are anxious and quite rightly worried about their children. It is our job to confidently assess and formulate a safe plan and convey this plan to the parents and reassure them.
· Where considerable distance or barriers exist for accessing help e.g. not local to an ED for self-presentation or remote areas where ambulance response may be lengthy
Safe Discharging/ Safety Netting and Worsening Advice:
So we have utilised evidence-based guidelines to come to a diagnosis of bronchiolitis and decided the child is safe for discharge. So how do we facilitate a safe plan to discharge at home:
We need to reassure patients about the process of bronchiolitis and the likely course of the illness dependant on where the child is within the disease process, specifically if we suspect they will be at the point of improving or if there is potential still to worsen. Remember the only active treatment hospital can provide is oxygenation/ ventilation support and feeding support if we cannot maintain these at home. We should encourage continued attempts at feeding, consider more often less volume as this may help. The most important thing is to thoroughly discuss through the red flag symptoms and the parents need to watch out for, these are: [3] [15]
· Worsening work of breathing (physically talk through the signs of recession, accessory muscle use, tracheal tug and nasal flaring so parents are comfortable identifying these.
· Ask parents to be aware of fluid intake. If intake drops below 50-75% or there is no wet nappy for the previous 12 hours
· Any episode of apnoea, grunting or cyanosis
· Evidence of exhaustion/ listlessness/ severe agitation and is not consolable with parents
· Becomes pale, mottled or feels cold to touch
· Develops a rash that does not disappear with pressure.
· Child under 3 months who spikes a temp over 38°C.
· Is getting worse or the parents are worried.
We should take this opportunity to give smoking cessation advice to the parents and express the importance of this especially whilst the child is ill.
Also reassure the parents that the cough component often persists for 2-3 weeks after the patient other symptoms resolve. This is important as it will reduce unnecessary further calls to primary/ urgent or emergency care services as the parents will understand what to expect.
It is good practice to provide written worsening advice also as verbal advice may not always be taken in. The healthier together website is a really good resource for this as it contains a wide range of parent safety netting and discharge advice leaflets that can be printed, loaded onto a smartphone or even a link SMS text messaged to the parents phone for them to open. By providing written worsening advice from a reliable source this significantly improves the safety netting process and adds good standards of governance and defensibility.
High or likely suspicion of another differential diagnosis such as pneumonia, sepsis or congenital heart disease should make us consider transport for further investigation and period of monitoring.
Last bits!
Hopefully, this has been a useful summary of Bronchiolitis to support your practice! Don’t just take our work for it… navigate to the other resources to supplement your learning and make sure to reflect on this CPD in your portfolios.
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