Trial by Inhaler - Bronchiolitis vs Viral Wheeze

With wheeze in children becoming a major presentation again, it feels like a good time to explore the issue of deciding whether a child has bronchiolitis or viral induced wheeze.  There are various way that people do this in practice.  Many stick to a strict 12 month cut off.  This method works reasonably well and is rarely problematic.  Bronchospasm is rare below this age and if it is going to be problematic under the age of 12 months, in my experience the infant is severely distressed and gets bronchodilators out of desperation rather than a diagnostic trial.

I have already explored a method of determining whether the pathology causing wheeze is predominantly wetness (bronchiolitis) or tightness (viral induced wheeze/ bronchospasm) by using age combined with the story.

Slow accumulation of moisture and mucous tends to cause worsening of symptoms over days whereas bronchospasm causes acute change over hours.  My opinion is that in the majority of cases, the age and the story will correlate.

Where the patient is in the overlap zone (e.g. 10-15 months old) and the story is clear (e.g. snotty/ coughing on Monday, struggling with feeds on Tuesday, noisy breathing on Wednesday and fast breathing on Thursday) then the story gives the diagnosis.  With age/ story correlation or where the age allows ambiguity but the story is clear, the diagnosis is made.

So what about simply trying an inhaler to see if it works?  This alternative approach to the age of overlap sounds straightforward and is reasonably common in practice, but is it logical?

A therapeutic trial works best when a clinical effect is guaranteed and unambiguous.  Neither of these things is true in this situation.  With viral wheeze, which should respond to salbutamol, clinically apparent response may require increased or repeated doses.  Bronchiolitis, which will not respond, is famous for mini-fluctuations in work of breathing.  This is caused by mucous plugging or the clearing of secretions.

When you think of it in these terms, trying an inhaler doesn't meet the quality standards required of a valid test.

Trial by inhaler is also problematic due to human bias.  Uncertainty is fertile ground for biases to mislead us when an inhaler is given to make a diagnosis rather than as treatment.  It is better to use beta-agonists therapeutically where appropriate and to see non-response as a reason to reconsider a presumed diagnosis of viral wheeze.  If viral wheeze is the problem, we should not allow the lack of effect to refute the diagnosis.

Edward Snelson

@sailordoctor

Disclaimer - when I wrote this, I briefly thought that you could bring logic to medicine.  I know, right?!?

Ipratropium for infant wheeze - a Christmas stocking stuffer

On the run-up to Christmas, this site will be delivering some rather minimalist FOAMed.  Instead of comprehensive explanations, there will be some short but hopefully useful posts for you to enjoy.  Think of them like a stocking stuffer rather than your main present.  Perhaps you'll like this format even better.  [I will never forget the year that my children played more with one of their stocking stuffers than with their main present.  That stocking filler present was a whoopee cushion.]

Here it is:

That little caveat at the end is about the use of ipratropium as an additional agent in the treatment of severe/ life-threatening brochospasm due to viral wheeze.  In that scenario, it's still very much all about the salbutamol.

That's all folks.  If you wanted something bigger, you'll have to wait until we're opening the main Christmas presents, or you could read this post that goes into more detail about infant wheeze diagnosis.

I hope you're looking forward to your next stocking stuffer.

Edward Snelson

@sailordoctor

The Decision Maker's Guide to Bronchiolitis Assessment

 This bronchiolitis season is going to be different.  While SARS-CoV2 virus does not seem to be a significant cause of wheeze in children (1), all the other usual viruses are still out there and will be causing wheeze soon in a child near you.  What might have changed is how we make decisions about that child.

For the purposes of exploring our decision making, it is important to define bronchiolitis as a condition that is a virally induced inflammation of the small airways of the lungs in a child, typically under the age of 1.  It is clinically distinctive from viral induced wheeze which is virally induced bronchospasm of the large airways, typically in a child over the age of 1.  For a separate article on differentiating these two conditions, click this link.

The necessary decisions regarding bronchiolitis haven't changed.  What might change during a global pandemic is the outcome of those decisions.  Hospitals have always been dangerous places, with a significant risk of hospital acquired infection.  That risk has escalated due to the prevalence of the highly infective SARS-CoV2 virus.  Though very unlikely to cause COVID-19 infection in children, there is that risk, the risk of PIMS-TS and the risk of COVID-19 to the accompanying adults.

The aim in bronchiolitis decision making has always been to keep as many children out of hospital as is safe to do so.  In order to do that expertly, we just need to make three decisions.

1. Does this child have bronchiolitis?
2. Should this child be managed at home or in hospital?
3. What treatment should the child be given?

Question 1: Does this child have bronchiolitis?

Most children under the age of 1 year presenting with a tight cough, wheeze, respiratory signs and poor feeding have bronchiolitis.  There are other possible explanations for that presentation however and it is important to know about these other possibilities.

Viral induced wheeze, which involves bronchospasm is separate from bronchiolitis.  Clues that it may be viral induced wheeze include the age of the child (most commonly over 1 year) and previous episodes of viral induced wheeze.  The other clue is the onset of the respiratory changes.  Bronchiolitis is a slow accumulation of wetness in the airways and the history is typically of a gradual and progressive worsening of symptoms over days.  Viral induced wheeze, due to the bronchospasm involved, presents with a more sudden onset of wheeze and distress, often going from normal to significantly abnormal over a few hours.

Pneumonia is almost never associated with wheeze in children (2).  Focal crepitations are often heard in a viral lung infection of any kind.  The presence of wheeze strongly suggests that the signs and symptoms are virally induced in some way.  Infants with pneumonia will tend to be significantly unwell.  The simple rule of thumb is this:  If the infant has a wheeze and is well enough to be managed in a pre-hospital setting, they do not have bacterial pneumonia.

Congestive cardiac failure (CCF) due to haemodynamically significant yet undetected congenital cardiac abnormalities is a rare mimic of bronchiolitis but one that is important to be aware of.  The typical cause is a large ventricular septal defect (VSD) causing a significant left to right shunt.  This increased pressure through the lung circulation causes pulmonary odema which manifests as poor feeding, fine crepitations and wheeze.  Thankfully, most significant heart defects are detected before a baby is discharged from postnatal care, but occasionally one slips through and the signs and symptoms are easily mistaken for bronchiolitis.

There are usually clues however.  A murmur is the most obvious clue but this can be difficult to hear at >160bpm.  An excessive tachycardia is a possible sign of CCF.  A significant hepatomegaly (normal babies often have up to a centimetre of palpable liver) is highly suspicious of CCF.  Finally, the progression of symptoms does not fit for bronchiolitis as they continue to get worse after the 3-4 days in which bronchiolitis reaches its peak.

Putting these things together, it is usually possible to be confident in diagnosing bronchiolitis as long as the history and findings are consistent with bronchiolitis and not one of the other pretenders.

If the diagnosis is bronchiolitis, we can move onto our next question:

Question 2: Should this child be managed at home or in hospital?

Most children with bronchiolitis can be managed in the community.  Keeping people away from hospital where it safe to do so has never been more important.  In the UK, the NICE guidelines for bronchiolitis (3) give recommendations for when to refer and when to consider referral.

Referral is always recommended for red flags.  In the NICE guidelines, these are a combination of signs of potential respiratory failure.  Notably, apnoeas are included as a stand-alone red flag.  That means that a child without any chest signs of severe respiratory distress should still be referred if they have had episodes where they appear to stop breathing.  The reason for this is that in such cases, immature respiratory drive may be a factor.  Following an apnoea, a baby can temporarily seem much improved but may go on to have further events and deteriorate suddenly.

Feeding and hydration is probably the least well defined element of the decision making element.  The guidelines ask the clinician to consider a variety of factors, however being able to assess whether the amount of feeding is adequate is next to impossible apart from overt signs of dehydration.  We never know how much a breast fed baby is getting unless the answer is "nothing."  If the baby is bottle fed, applying a percentage to that as being adequate doesn't take into account the fact that many bottle fed babies take much larger volumes as a baseline.  As a result, the most objective measure of adequate feeding has to be signs of hydration or dehydration.  For that reason, I have included clinical dehydration in the list of red flags and beyond that, feeding difficulties remain a matter of clinical judgement when it comes to referral.

Possibly the most controversial element of the decision making is the presence of risk factors.  In the guidance, it is stated "When deciding whether to refer a child with bronchiolitis to secondary care, take account of any known risk factors for more severe bronchiolitis such as... (e.g.) premature birth, particularly under 32 weeks."  The guideline evidence statement lists the basis for each risk factor listed and with the exception of neuromuscular disease, the committee acknowledged that there is no credible published evidence for the other risk factors.  Apart from neuromuscular disease, they are all consensus opinion recommendations.

So what are you supposed to do when you see an 8 month old baby with mild bronchiolitis, no red flags and adequate feeding when you know that they were born at 31 weeks gestation?  Do you send them to secondary care in case because they have a risk factor for severe bronchiolitis or do you keep them well away from hospital because they don't have severe bronchiolitis and you don't want to add a hospital acquired infection to their list of problems?

Balancing risk vs benefit is what it is all about here.  There is a known risk of hospital acquired infection vs an unknown risk of severe bronchiolitis.  There is also no evidence that admitting high risk children with bronchiolitis is any safer than good safety-netting advice.

If the decision is made to manage a child with bronchiolitis at home, the third and final question is:

Question 3: What treatment should the child be given?

There has been a load of research done to try to find an effective treatment for bronchiolitis.  Supportive interventions (oxygen, CPAP etc) in the cases where respiratory support are needed have been shown to be effective.  Each and every other therapy have in turn shown to have no benefit for mild to moderate uncomplicated bronchiolitis.  Therapies proven to be ineffective include β-agonists, ipratopium, hypertonic saline, antibiotics and corticosteroids.  The bottom line is that for a child being managed in the community, no pharmacological treatment should be given.  This recommendation is consistent  across guidelines from the UK, USA and Australia (3,4,5).

That makes this flowchart nice and simple:

Finally, you might be asking yourself if you are an expert decision maker when it comes to a small person who has a cough and wheeze.  Hopefully this post helps you to feel that you are.  Decision making in such children is all about recognition, knowing the red flags and above all, learning that if in doubt, looking at the child will almost always give you your answer.

Edward Snelson
@sailordoctor

References

1. Roland D, Teo KW, Bandi S, et al COVID-19 is not a driver of clinically significant viral wheeze and asthma Archives of Disease in Childhood Published Online First: 16 October 2020. doi: 10.1136/archdischild-2020-320776
2. Hirsch A, Monuteaux M, Neuman M, Bachur R, Estimating Risk of Pneumonia in a Prospective Emergency Department Cohort, Paediatrics, Vol 204, p172-176.E1, Jan 01, 2019 doi:10.1016/j.jpeds.2018.08.077
3. Bronchiolitis in children: diagnosis and management, NICE guideline [NG9] Published date: 01 June 2015
4. American Academy of Pediatrics Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis, Pediatrics November 2014, 134 (5) e1474-e1502; doi: 10.1542/peds.2014-2742
5. The Royal Children's Hospital Melbourne Clinical Practice Guidelines: Bronchiolitis

The NYCE guideline for viral induced wheeze - Let's clear a few things up

If you’re unsure about how to manage viral wheeze in children, you’re not alone.  There is much confusion about this common paediatric presentation.  The uncertainty about best management exists for several reasons.

• Research: The research on interventions is usually age based rather than specific to the condition being treated.
• Guidelines: There are very few guidelines specifically for viral induced wheeze.  No national guidelines exist.  Some centres use asthma guidelines for acute treatment of viral wheeze while some develop  local guidelines which have significant variations.  
• Front-line: There is often uncertainty about the diagnosis.  Telling the difference between bronchiolitis, vial induced wheeze and asthma/multi-trigger wheeze can be a challenge.

When you see a wheezy child, you want answers to all these questions.  So here we go, one at a time.

Question 1 – Does this child have viral induced wheeze?

If the child in front of you is snotty and between the ages of 12 months and 5 years then the answer is “almost certainly.”  Almost is somewhat unsatisfactory so here is the breakdown of that statement.

Wheezy children under the age of 12 months usually have bronchiolitis, a condition that is also induced by a virus but involves wetness of the small airways rather than bronchospasm of the larger airways.

Wheezy children over the age of 5 years might still have viral induced wheeze but asthma is a more significant possibility in this age group.  Children under the age of five may also get wheezy with other triggers but there is debate about what this should be called (e.g. multi-trigger wheeze) and when a diagnosis of asthma is given under the age of five it can easily turn out to be wrong.

The most certainty about the diagnosis of viral induced wheeze exists in those children between the age of 12 months and 5 years who

• Only wheeze with a viral illness
• Have a relatively rapid onset of wheeze
• Have demonstrated response to beta-agonist treatment

It is worth knowing that there are wheezy presentations in this age group that can look a lot like viral wheeze.  These include bronchomalacia, acute allergy, and cardiac failure due to e.g. acute myocarditis.

Question 2 – What and how much treatment should I give to a child with viral induced wheeze?

Treatment of acute viral wheeze is often extrapolated from asthma guidelines.  Most, such as the BTS guidelines, stratify according to severity, mainly based on signs of increased work of breathing.

Other factors to consider include the child’s previous history of wheezy episodes.  It is reasonable to treat children who have progressed to needing a critical care level of treatment on previous occasions more aggressively in terms of treatment and more cautiously in terms of admission.

It is also well worth considering is whether the child has received effective treatment prior to presentation.  If the child has either been given no inhaled beta-agonists at home or the delivery has been ineffective, they are more likely to respond to a more conservative dose of inhaled treatment.  If they have been given substantial and effective treatment at home and are working hard to breate despite this, they are more likely to need a larger number of puffs to achieve an improvement.

Here is an example of how to treat an acute viral wheeze at presentation to primary care:

The use of oral steroids in children with viral wheeze is controversial.  Much of the available research looks at wheezing within an age group, not categorising children into phenotypes of underlying cause.  This has led to age based approaches by some and a selective approach to using steroids by others.

The best evidence (1) for the use of oral steroids for viral wheeze between the ages of 1 and 5 would suggest that the following group are most likely to have a small benefit:

• Children with a diagnosis of asthma
• Children who have required substantial amounts of inhaled beta-agonist prior to presentation
• Children whose severity and lack of response to treatment with beta-agonists requires admission to hospital

One simplified application of this evidence is to say that if the child does not have asthma and does not require in-patient treatment, there is too little evidence to support the routine use of oral steroids.  Note that a family history of atopy, though often used in decision making here, is not an indicator that the child is likely to benefit from steroids.

Question 3 – Should this child be admitted?

The answer to that will depend on various factors including clinical setting and local infrastructure.  In an urban primary care/ secondary care model, admission should be the norm in the pre-hospital setting for children with a moderatel or severe episode who have required significant quantities of salbutal and are not responding well. 

Children whose severity is judged to be mild, and those who are moderate at presentation but respond well to their first dose on inhaled beta-agonist can usually be managed in the community.

Risk factors such as prematurity, comorbidities, pervious life-threatening episodes, parental confidence/competence and adverse social circumstances should all be involved in this important decision.

Question 4 – How much beta-agonist should the parents give if I am sending them home?

There is huge variation in practice here.  Experience tells us that paradoxically children tend to need larger doses of inhalers rather than standard or small doses.  This is likely to be due to a combination of delivery (getting all that is given to where it will count) and physics, since children’s airways have different flow dynamics to adult airways.

The majority of clinicians will recommend that the child receives 6-10 puffs of salbutamol 3-4 hourly.  Note that local guidelines vary in terms of dose and interval.  There is a certain amount of clinical judgement involved which will be influenced by the presentation and the circumstances (including the parental confidence and competence with delivery of inhalers and their ability to recognise markers of deterioration.)

What guidelines often fail to explain are the aims of treatment at home.

• To get the child’s breathing looking normal or nearly normal
• To maintain that improvement for at least a couple of hours and ideally four hours
• To prevent the viral wheeze from affecting the child’s activity, ability to feed etc.

It is useful to tell parents that the inhalers will not treat the symptoms of the viral illness such as cough and runny nose.

Treatment failure is generally considered to be:

• Significantly increased work of breathing despite inhaled beta-agonists
• Worsening severity – progressively requiring more puffs or more puffs at shorter intervals
• Parental global concern about the appearance or wellness of the child

A further variation in practice is how people manage the issue of reducing/ stopping the inhaled beta-agonist treatment.  Viral wheeze is by definition a time limited problem.  As the effect of the virus and the child’s immune response resolve, so does the bronchospasm.  There are two main approaches to the way that people advise how to move towards stopping the inhaler.

• A set weaning regime – many centres have a planned weaning regime for inhalers that is given to parents.  This sets out a planned reduction of the number/ frequency of inhaler given to the child.  It is usually written down and given to the parents for them to follow.
• A weaning plan that is not prescriptive – it is equally common to give parents a plan that puts them in the driving seat.  Often, it recommends a set dosing and interval for a set period (e.g. 6 puffs four hourly for two days) to be followed by a period of using the inhaler when it is apparent that the child would benefit (e.g. increased work of breathing or audible wheezing).

Each approach has pros and cons.  A set weaning regime carries a risk that the parents will follow it even when the child is not ready.  A weaning regime that requires parental judgement carries a risk that the inhalers will continue to be given when not needed (e.g. to treat a cough) or that the parents will simply stop after two days and not recognise the child’s need for further inhalers.

Whichever approach is used, the risks can be managed by careful explanation of what to do, how to do it and when to divert from the plan.

It's important to know the uncertainties and variations in practice.  It's also important to have a guideline.  Viral wheeze has always been a paradox in that regard.  There is a broad concensus that viral wheeze is not asthma, yet there has always been a tendency to shoe-horn the management of viral wheeze into asthma guidelines.  Perhaps it is time that viral wheeze had its own guideline.  Wouldn't that be NICE.

Edward Snelson

@sailordoctor

References

1. Foster S et al, Oral prednisolone in preschool children with virus-associated wheeze: a prospective, randomised, double-blind, placebo-controlled trial, Lancet, Vol 6, Issue 2, P97-106, Feb 01, 2018

Chest X-rays in children - The Wimbledon Rules

We've come a long way in terms of reducing unnecessary tests in paediatrics.  It is within my career that it was standard to obtain a chest X-ray (CXR) for any child presenting with their first episode of wheeze.  Now, such an approach is seen as outdated.  This is a good thing.  In fact the vast majority of acute and sub-acute respiratory presentations in children can be managed without needing a CXR.

In some ways it was a lot easier to know when to do a CXR 20 years ago.  The answer was pretty often.  Every lower respiratory tract infection (LRTI), every first episode of wheeze and every persistent cough tended to result in a CXR.  Now, we should rarely do CXR in those circumstances.  Rarely doesn't mean never though, so how do you know if you're doing too many?  Enter the Wimbledon Rules for CXR in children…  I’ll come to that later.  First, I’ll explore a little bit about the complexities of doing CXRs in paediatrics.

The problem with CXR in children is that it can be misleading.  The most common scenario in which this is true is for the wheezy child.  Wheeze is a strong negative predictor of pneumonia(1).  This makes sense clinically when you think about it.  If an infant or child has restricted lower airways, that is reason enough to have respiratory distress.  If you then take a section of lung out of action, you won't be wondering if they might have a problem.  It is likely to be very obvious from how unwell they are and how abnormal their breathing is.  As a rule, children with tight airways and pneumonia together are in a very bad way.

While wheeze is a strong negative predictor of pneumonia, a CXR in wheezy children is rarely clear.  In many cases there is a patchy white area on the CXR.  This is often at the right heart border, or as it is sometimes called, "the area of radiological romance."  If you do a CXR too often in wheezy children, this will happen fairly frequently and it may be difficult to ignore.

Even if a child does have a LRTI, CXR is not necessary in many cases.  The British Thoracic Society (BTS) guidelines for community acquired pneumonia (CAP) recommend the following:

• Chest radiography should not be considered a routine investigation in children thought to have community acquired pneumonia. 
• Children with signs and symptoms of pneumonia who are not admitted to hospital should not have a chest x-ray.

These recommendations are based on two important facts.

• Children with clear clinical signs of CAP may have a normal CXR
• Children with abnormal findings on a CXR often do not have clinically significant CAP (2)

So when should we do CXR in children?

Let’s start with the times when CXR is not recommended routinely:

• Bronchiolitis not requiring admission to a critical care unit (PCCU)
• Episodes of asthma and viral wheeze (no matter how severe or whether it is the first episode of wheeze for that child) which are responding to treatment
• Community acquired pneumonia without atypical features and which responds to treatment within the first two days
• Most cases of cough without other features
• Chest pain in children

CXR is usually most helpful in children in these circumstances

• Severe exacerbations of asthma or viral wheeze which are getting worse despite appropriate treatment 
• Community acquired pneumonia which has atypical features or fails to respond to appropriate treatment
• Daily cough with any of the following features
• Lasting more than 8 weeks
• Progressively worsening over several weeks, esp. if moist cough
• Red flag features (daily fever, night sweats, weight loss)
• Known exposure to TB
• History consistent with inhaled foreign body

The other side of the problem is that there is no gold standard test for many of those clinical scenarios where CXR is not routinely recommended.  There is often poor correlation between clinical and radiological findings, but which is more valid?  For example if you take pneumonia in children and treat based on radiological findings versus clinical findings you will end up treating different children.  Clinical findings will be falsely positive and falsely negative just as radiological findings are.

Therefore we need to get a balance between clinical common sense and judicious use of CXR in children.  A simplistic approach which could be applied looks like this:

Whether a CXR is necessary or not is highly subjective.  Ask ten clinicians and you'll get ten different answers, due to the human factors.  It's a little like an umpire in a tennis game.  They're not right all of the time.

For this reason, in a major tournament tennis game, players are allowed to appeal.  However the players appeals are limited.  If they appeal against a decision and that appeal is upheld, they retain the number of appeals that they had before the appeal.  So wrong once, they can appeal again.  Wrong twice and they're out of appeals.

I suggest that clinicians should apply the same rules to the use of CXR in children.  Before doing a CXR, we should ask ourselves the question, "What would I do based on a purely clinical assessment?"  After doing a CXR, we should then ask, "Has the CXR added genuinely useful information to my clinical decision?"

Having a CXR result in a child which doesn't alter our clinical decision, or which dysfunctionally suggests a pathology in the absence of a congruous clinical picture should make us rethink our approach to our use of CXR.  If we're going to apply the Wimbledon CXR rule, when we get one completely normal CXR (or one with a non-descript small white fluffy patch which makes us want to give antibiotics when we wouldn't have done so before the CXR) we should think about more cautious use of CXR. If we get two, we should stop and re-read the rules.

Just as tournament tennis players don't have an unlimited number of appeals, we shouldn't think of CXRs as an unlimited diagnostic resource.  We should use them when they are most likely to change our game.

Edward Snelson
Unappealing Paediatrician
@sailordoctor

Disclaimer: If you turn the umpire off and back on, the number of appeals resets.

References

1. Hirsch, A. et al., Estimating Risk of Pneumonia in a Prospective Emergency Department Cohort, The Journal of Pediatrics, Volume 204, 172 - 176.e1
2. Virkki R, et al. Radiographic follow-up of pneumonia in children. Pediatr Pulm 2005;40:223e7.

Making the Right Judgement - a comprehensive 3D model for deciding what to do with each child with a respiratory presentation

In the previous post, I covered how best to make a diagnosis of lower respiratory tract infection (LRTI).  Anyone who has the pleasure of working with acutely ill children knows, the diagnosis is only a small part of what we do.  A big part of what we do is making that all important decision - home or hospital?

This decision is usually made up of several elements.  What is interesting is that the same principles can be applied to all of the major respiratory problems that we see, namely:

• Bronchiolitis
• Viral Wheeze
• Asthma
• Croup
• Pneumonia (LRTI)

Once one of these diagnoses has been made, the decision about whether to admit or manage at home is a huge one.  On the one hand, we don't want to admit children to hospital unnecessarily.  Apart from the inconvenience and stress to the family, there is a significant risk of adding insult to injury as so many children who attend hospital acquire additional infection.  On the other hand, we know that if a respiratory problem does deteriorate, it can do so quickly and catastrophically.  If there is a significant risk of a child going off, they should be somewhere that can respond appropriately.

In the majority of childhood respiratory illnesses, the treatment itself is not what requires the child to be in hospital.  It is no longer routine to have a chest X-ray and intravenous antibiotics for uncomplicated community acquired pneumonia. (1)  Many children who are admitted with pneumonia receive no investigations and are treated with oral amoxicillin and discharged when they show improvement.  Severe croup is often a waiting game.  Viral wheeze is usually treated with inhalers via spacer.  Babies with bronchiolitis are often observed while a team of expert paediatricians avoid the temptation to "try something" that research has proven to be pointless.  You get the picture.  These are the times that paediatrics is the art of masterful inactivity.  Believe me, that is harder than it sounds and is actually quite labour intensive when done properly.  The point is, they still need to be there, because these are the children who, if they got worse, would require escalation of treatment.

So if the need for hospital specific treatment isn't always the thing that determines the need for admission, what else is?  In illnesses that always need hospital treatment (e.g. Kawasaki Disease) the decision is made for you.  However in respiratory problems that can be treated in the community, the decision is mostly about risk assessment, which is never as simple as people make it sound.

Guidelines often imply that the assessment of a respiratory presentation is a simple matter of deciding severity or calculating a score.  I like an over-simplification as much as the next clinician, except when it doesn't work, which is fairly often.  Why isn't it that simple?  Because not a one dimensional assessment.  The good news is, it's not that complicated,  It's just 3D instead.

D1 - Severity

The first dimension of the assessment is to decide severity.  All acute respiratory problems, like chain coffees, come in small medium and large.  Deciding which presentation fits into mild moderate or severe is fairly intuitive and the same principles apply across the different diseases.

Severe makes the decision easy.  Severe needs to be treated in hospital for several reasons.  Severe is usually a set piece, and although severe can be terrifying, it's not usually a cause of decision fatigue.  That comes from deciding what to do with the rest of them.

In a previous post, I shared some thoughts on croup scores and severity.  You can read that via this link if it would be helpful.

Mild cases of croup, bronchiolitis, viral wheeze, asthma and LRTI are almost always best managed at home.  Almost.  Moderate cases can often go either way.

D2 - Risk factors

This means that other factors are involved in the decision.  Because we are assessing risk, we need to consider risk factors.  These, when applied to the severity of the illness literally multiply the risk of something bad happening.

As a rule, a risk factor alongside a moderate severity of respiratory problem is ore than enough to mandate admission to hospital.   That child with croup that you were thinking of sending home- I suspect that decision will be changed when you factor in the fact that they were born prematurely at 26 weeks.

What is slightly more complicated is how risk factors apply to the child with a mild presentation.  It's complicated because the presence of a risk factor does still ramp up the risk, but its a factor applied to a very small risk in the first place.  What's more, the same risk factors that apply to the presentation also apply to the risk of being in hospital.  An ex-premature baby with mild bronchiolitis could go off, but the risk is still small.  An ex-prem baby in hospital if they don't need to be is a risk all of its own.

The decision about what to do with a child who has a mild respiratory problem but also has risk factors is a difficult one.  It is a decision best made by an experienced clinician who understands the way that the particular risk factor interacts with the illness and knows the pitfalls associated with it.  If you're not sure, refer or discuss the case.  This may be a good opportunity for an experienced primary care clinician to share that decision with an experienced paediatician via a telephone consultation.

D3 - Red Flags

Finally, there are red flags.  Although independent of the apparent severity of the presentation, these features will usually mandate referral or admission.

A good example of a red flag feature would be a 4 month whose clinical examination is consistent with mild bronchiolitis.  If the accompanying adult says that the infant had an episode of suddenly becoming pale and floppy earlier that day, this should be treated as a warning sign.

Bringing those three dimensions together will give you the answer to the "home or hospital?" question.  It will also help the communication between primary and secondary care.  Referring a child with a respiratory problem, summarised as diagnosis, severity, risk factors and red flags is just showing off.  There's nothing wrong with that is there?

Edward Snelson
Dimensional Relativist
@sailordoctor

Disclaimer: I'm never sure which is worse: oversimplification or undersimplification.

References

1. Guidelines for the management of community acquired pneumonia in children: update 2011 British Thoracic Society Community Acquired Pneumonia in Children Guideline Group

Why Do Different Children Wheeze Differently? - Simple, but first you have to understand all of paediatrics (also simple)

When a child or young person has one or more wheezy episode, there are various possible causes.  The vast majority of paediatric wheeze is caused by bronchiolitis, viral wheeze and asthma.  It is easy to confuse these conditions, but clarity of diagnosis has real benefits when it comes to providing evidence based treatment.

We know that getting the diagnosis right isn't straightforward, possibly because there are no tests which reliably distinguish these entities from each other in children.  For example, evidence suggests that 50% of children diagnosed as asthmatic do not have asthma (1).  One knock-on effect of any diagnostic difficulties is that people make up rules for us.  "Asthma should not be diagnosed under the age of 5 years."   "Inhalers don't work under the age of 12 months."   These rules are meant to be helpful, but they are both wrong.  If you were only playing the odds, living by these rules would be the way to go, but clinical medicine is also about pattern recognition.  If it looks like a duck etc.

I think that it is possible to embrace the rules, while also knowing when to break them.  I believe that there is a simple model for understanding paediatric wheeze which fits into the probability model and the pattern recognition model.  It's fairly simple and all it requires is a good understanding of all of paediatrics.

Paediatrics isn't the art of learning 30,000 rare conditions.  Paediatrics is mostly about understanding what conditions affect children at different ages and how children respond to those illnesses.  That in turn allows us to recognise and treat appropriately wherever possible.  When it comes to infections and immune responses, unsurprisingly the immune system plays a big role.  Of course a child's immune system goes through several stages and each one dictates a different response to infection and allergens.

How does a baby fight infection?  In simple terms, they don't.  Inherited antibodies do most of the work for the first few months.  Few pathogens get past these antibodies and so the baby's own immune system does very little.  This has lots of implications.  Infections that do occur are unlikely to be common viral illnesses and whatever the pathogen, the baby will be at greater risk from that infection.  Even the recognition of an unwell baby is affected by their lazy immune response.  Temperature of 40C in a 7 day old?  Pull the other leg.

These maternal antibodies eventually run out.  The immune system has to learn and develop.  Older children, like adults have a complex and clever immune system which has stored a wealth of information about the pathogens in their environment.  This allows the older child to produce a response to infection that is not just complicated but sometimes over-complicated.

So how does a human survive in-between losing maternal antibodies and learning a more complex immune response?  In scientific terms, their immune system goes nuts.  You have seen it yourself: even with a relatively simple and uncomplicated viral infection, the younger child can have very high temperatures, various rashes and of course viral wheeze.  Other things that are common in this age group are quite possibly in part due to this exaggerated immune response - irritable hips and febrile convulsions.

These three ways of responding to infection align very nicely with the three entities that commonly cause wheeze at different ages in children.

So, the rules about age do have a solid basis.  Would you diagnose asthma when a six week old becomes wheezy?  Please don't.  Would you diagnose bronchiolitis in a 12 year old?  No.

Age alone does not give you the diagnosis since there is some overlap.  Thankfully, because each condition represents a different immune response, they each present with slightly different clinical features. As a result we can combine probability with pattern recognition.  The best bit is that the pattern recognition fits well with these three immunological stages of childhood.

What happens when you are a baby and a virus causes a respiratory tract infection?  In most cases, the answer is simply wetness.  Bronchiolitis is what you might expect from an immune system that has not yet fully woken up from its cocoon of maternal antibodies.  Bronchiolitis tends to slowly progress over days from cough and coryza to wheeze and suboptimal feeding, finally ending up with a variable degree of respiratory distress.  It progresses over days.  The severity and progression of these symptoms will vary from child to child, however the gradual onset is characteristic.  This is not to be confused with deterioration, which can be sudden, especially in high risk babies.

Viral wheeze by contrast tends to come on quickly, over hours rather than days.  This is because in viral wheeze is a different response to the same viral trigger.  In children between the ages of about 1 and 6, when the immune system sees a new virus, it tends to go a bit crazy.  One of the effects of this immuno-enthusiasm seems to be that that many children experience bronchospasm as part of that immune response.  So in addition to being able to tell which is more likely (bronchiolitis or viral wheeze) by the age of the child, the rapidity of the onset of the wheeze is a clue.

Why does it matter that we tell the difference?  These two different entities respond differently to treatment.  The slow development of inflammation and wetness in the airways that is bronchiolitis does not respond to bronchodilators while the bronchospasm of viral wheeze does.  This is probably the reason for the perpetuated myth that children under the age of one don't respond to beta-agonists.  They do, but only if they have bronchospasm (viral wheeze) as opposed to mostly wetness (bronchiolitis).

Finally, when your immune system moves from the "shoot first, ask questions later" mode into adult mode, asthma becomes the most common cause of wheezing in children and young people.  The trouble is that this isn't something that happens suddenly and it certainly isn't the case that there is a consistent age for this to happen.  Once again though, odds are very much affected by the age of the child.  Does the 8 month old have asthma?  No.  Does the 15 year old have episodic viral wheeze.  Almost certainly not.  Once again, the fact that the different entities represent different stages of immune system maturity translates into both probability and pattern recognition.  The 3 year old is probably having episodes of viral wheeze, but this will be confirmed by the fact that all episodes are precipitated by viral illnesses and the lack of interval symptoms.  The 10 year old probably has asthma and if this is the case they will be having episodes of wheeze not just when they get viral illnesses.

This explains the contradictions between all of the things that we know about asthma in children.  We are told that we shouldn't diagnose asthma under the age of five.  That rule works well from a probability point of view but not from a pattern recognition point of view.  What would you do if a 3 year old has a chronic cough and multiple episodes of wheeze that are not all provoked by viral illnesses?  I think that this child might be the exception to the probability rule.  Equally, in a 2 year old with chronic cough and no history of wheeze the temptation to diagnose asthma is a dangerous one given both the lack of  probability and the absence of a classic history.

Understanding the way that children respond to infection at different ages tells us a lot about where (what age) to look for each diagnosis and what to expect (the classic history) to find in order to confirm that diagnosis.  This allows us to maximise the chances of giving the most appropriate treatment, most of the time.

When there is a discrepancy, we need to be aware that probability and pattern have not agreed, and have a low threshold for rethinking.

Edward Snelson
Occasional rule analyst
@sailordoctor

Disclaimer: No-one understands all of paediatrics.  I mean really, who can explain why children will eat glue and drink air freshener but refuse to eat the food that you want them to eat?  That's why it's best to stick to the basics (like immunology) and leave the complicated stuff to the parents.

References

1. Ingrid Looijmans-van den Akker, Karen van Luijn and Theo Verheij, Overdiagnosis of asthma in children in primary care: a retrospective analysis, Br J Gen Pract 2016; 66 (644): e152-e157

It's Not Easy Being Wheezy - about antibiotics and wheezy kids

In my formative postgaduate years as a doctor, I was told by more than one mentor that antibiotics were a good treatment for children who were wheezing. This advice was given by various people at different times and whether this was bronchiolitis, viral wheeze* or an exacerbation of asthma, the principles seemed to be the same. The logic is sound - we know that infection triggers all three, and we can never be certain of the infection being a straightforward viral episode.  That was how it was put to me anyway.
*If you are unsure about the difference between viral wheeze and bronchilitis, follow this link for an explanation.

I no longer believe in this strategy as a treatment option for wheezy kids, and this is why:

It's not easy being wheezy.  Children with tight lower airways are up against it but often cope extremely well with their bronchospasm or their bronchiolitis.  I am constantly delighted by the ability of these children to be cheerful despite quite significant breathing difficulty.

It's even worse to have a bacterial lower respiratory tract infection.  As well as the breathing difficulty that comes from the loss of functioning lung, there is the tiring effect of the illness.  Having pneumonia is unpleasant and often exhausting.  It would be unusual to see a child who was cheerful and well despite a bacterial lower respiratory tract infection.

Now imagine combining the two.  Doesn't look good does it?  Children with bronchiolitis and viral wheeze cope with the difficulties of wet or constricted airways because they are systemically well.  Add the lethargy of bacterial infection to this and you go from a child who can compensate to one who cannot.  In short, you won't think "maybe there's a bacterial LRTI as well as the bronchiolitis or viral wheeze."  You'll know it.

Evidence from research backs this up.  The Cochrane review of antibiotics for bronchiolitis concluded that there was no benefit from antibiotics. (1)

You could say, what's the harm in trying antibiotics?  There are many reasons why unnecessary antibiotics might be harmful and none of these are to do with drug resistance.

So, it's time to do away with the idea that antibiotics have a role in treating well children with bronchiolitis or viral wheeze.  I believe that you'll know the children who need antibiotics because they will be properly unwell.

Edward Snelson
Antibiotic Guardian of the Galaxy
@sailordoctor

Disclaimer:  Secretly we all know that antibiotics do treat viruses, but if you tell anyone, you'll be removed from the Magic Circle.

Reference

1. Farley R et al, Antibiotics for bronchiolitis in children under two years of age, Cochrane database of systematic reviews. 2010

If you don't like what you hear, change the tune. (What to do when you don't hear a wheeze in a child who should be wheezy)

Every now and then, a clinician will go to see a child who appears to have increased work of breathing and is well (in the way that children with viral induced wheeze usually are) but find no wheeze on auscultation.  How strange!

Making a diagnosis is a complex business.  It is such a complicated process that, most of the time, we don't really think about it at all.  This has been described as type 1 thinking (intuitive) in the context of clinical diagnosis. (1)  Most days, I do very little thinking.  When I come across something unexpected or unfamiliar, I am forced to come out of this unconscious automatic mode and think carefully and consciously (type 2 process) about what is going on.  I have to engage my cortex, and it hurts.

So, going back to this little scenario.  Let's say that the child is 2 years old and has has a cold for 3 days.  They are brought by his parents because they have noticed that his breathing is a little fast.  He looks well and is really quite happy with the toys in your room.  Snot bubbles from his nose as he comes and sits on his mother's knee.  Looking at his chest, he has mild subcostal recession and a mild tachypnoea.  When you listen to his chest, you hear...  breathing.

So, what most people do in this circumstance is to listen some more.  It is traditional to check your stethoscope for gremlins or signs of tampering before pushing the earbuds a bit harder into your ears before listening again.  However, there is no getting away from the fact that there is no wheeze, nor is this the silent chest that is so feared in asthma and viral wheeze.  In a silent chest, no breath sounds can be heard and the patient looks awful.  This child has breath sounds and looks well.

How strange.

The reason that it causes us to have a confused moment is that there are certain combinations of signs and symptoms that indicate a particular illness.  That is particularly useful in children's respiratory illnesses since no one sign or symptom is likely to be specific to an illness.  This is why cough and fever do not equal a lower respiratory tract infection.  We need to look for the presence or absence of other features to form a likely diagnosis.

So what we've got now is a mystery illness.  What causes a well child to have respiratory distress without a wheeze or stridor?

Your next move is simple.  Give the child inhaled (or nebulised if necessary) β-agonists.  I would go with 10 puffs of salbutamol via a spacer device.  Then sit back and watch the magic.

What will probably happen next is a little surprising the first time you experience it: a wheeze appears.  More importantly, the child's breathing improves.  So, what is going on here?

The answer to that would be science.  Science and music are happening and it goes like this:  In order to have a wheeze, there must be the correct conditions for this to occur.  A musical note needs the right amount of air flowing through a tube in the right sort of way.  The size of the tube matters quite a lot.  Ask any wind musician or organ player.

In these cases there is bronchospasm (caused by viral infection) but the conditions are not right to produce a wheeze for you to hear.  Of the parameters that affect the musical note (length of tube, diameter of tube and flow of air) you can change two with β-agonists.  You can't change the length of the tube but the other factors should respond nicely.

So, if you don't like what you hear, change the tune.  When your clinical diagnostic brain tells you that there should be a wheeze, you are probably correct.  If you were expecting a wheeze but don't hear one, by all means rethink your presumption.  If you are left with the same conclusion, then try the β-agonist trick.  It works a treat.

Edward Snelson
Soverynotamusician
@sailordoctor

Disclaimer: This is a very different thing from rechecking a blood pressure until you get the number that you want.  Very different.   Anyway, I would never do that.

Reference

1. Croskerry P, A universal model of diagnostic reasoning, Acad Med. 2009 Aug;84(8):1022-8.

Why bronchiolitis doesn't get better with inhalers and how understanding "why?" is better than "do that!"

There was interesting debate this week about using inhalers for bronchiolitis.  The interesting features included how heated it became (there was mild name calling and much "prove it" involved, rated PG) and how confident people were in expressing their views on social media about their differing clinical practice.  (Take it from me that you should be fairly sure of yourself before you put something out onto the interweb.)  To me what was most interesting was that the views, despite being polar opposites, where seen as fact.  I am going to assume that all involved want to practice the best possible medicine, but someone must be wrong mustn't they?

What do the guidelines say?  The American Academy of Pediatrics and the UK's National Institution of Clinical Excellence along with other institutions, have produced guidelines in the past few years, specifying that beta agonists and ipratopium should not be used, so why are such debates still happening?  I think that there are a few reasons.  One of these is that for medics, knowing what to do is not as powerful as knowing why, especially when it comes to changing practice.  For me, understanding a disease is much more effective as a learning process than being told, "This is the disease and this is the treatment."   I suppose it is because I already understood the reason why I was doing what I was doing (even if the understanding was flawed), so a diktat is not as powerful a persuader as a new and better understanding.

There is a perpetuated myth regarding beta-receptors and infants.  This myth comes from early studies that failed to find evidence of beta-receptors in infants.  Since then, (as early as 1987) research of better methodology (3) has proven that these receptors are there from birth.  The myth persists because (just as the news reports plenty of crises but not so many resolutions) we are often told things, but rarely does anyone untell us something.

Perversely, the beta-receptor folklore has done us no favours when it comes to trying to understand bronchiolitis and viral wheeze.  The uncertainty created by this myth makes clinicians think that a lack of beta receptors has caused the lack of response to salbutamol.  In fact, the child would respond just fine if only they had bronchospasm.

In bronchiolitis, there is no bronchospasm so salbutamol does not help.  In viral wheeze, ipratopium is a poor treatment and the old myth about ipratropium leads some to believe that ipratropium is the first line treatment for this age group when what they really need is plenty of salbutamol if they really do have bronchospasm.

When discussing the management of wheeze in infants, I often get the impression that people believe that bronchiolitis is just what you call viral wheeze in a child under the age of 12 months.  In fact this is not true.  Bronchiolitis is a separate entity, with different histopathology and a unique clinical pattern of illness.  There is a gradual unset of symptoms, peaking at day 3-4 and beginning to resolve at day 7-10.  Doesn't sound very spasmy does it?

Of course the confusion arises from the fact that both bronchiolitis and viral wheeze are caused by a viral illness.  They can both occur in a child around the age of 12 months old and they cause similar symptoms.  There is however a subtle but helpful difference in the way that they present.

The reason for this difference is a difference in mechanism.  While bronchiolitis and viral wheeze share a cause, the pathology is different because the effects on the airways are different.

I suppose that since it is unrealistic to think that all uncertainty can be removed, the question remains, what is the harm in trying a bronchodilator in all every case, just in case?  Here are a few possible reasons why it is going to make things worse if it isn't going to make things better:

It's always difficult when two illnesses have so much overlap, but there are genuinely good reasons to avoid unnecessary treatment for bronchiolitis.  Hopefully understanding why bronchodilators don't work helps the thinking clinicians to decide for themselves, rather than just being told what to do by guidelines.

Edward Snelson
Mytharchivist
@sailordoctor


Disclaimer:  I would like to express my appreciation to the children who allowed me to perform lung biopsies on them during their wheezy episodes.  Science thanks you.


References

1. Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis, American Academy of Pediatrics, October 2014
2. NG9 Bronchiolitis in children: diagnosis and management, NICE, June 2015
3. A Prendiville et al., Airway responsiveness in wheezy infants: evidence for functional beta adrenergic receptors, Thorax. 1987 Feb; 42(2): 100–104.

High Voltage - What the diagnosis plus severity means for management of viral wheeze

In the previous post, I concentrated on giving the correct label to the child under the age of five with recurrent episodes of wheeze.  I'd like to pretend that that makes the management simple but I just can't do that.  Not only are the diagnoses confusingly difficult to tell apart sometimes but there are overlaps with treatment options.  So are there actually distinct clinical entities at all?

There are important differences between the two main groups: viral wheeze and asthma/ multi-trigger wheeze.  Once again though, I have to emphasise that viral wheeze is not a lesser diagnosis and can cause life-threatening exacerbations.   It is possible that there are just these two entities and that the viral wheezers need different treatment at the more severe end of the spectrum.  After all, high voltage can do bad things to a circuit.

What is particularly confusing for the generalist is seeing children with a diagnosis like viral episodic wheeze being given a steroid inhaler.  You might be excused for exclaiming WTF!  (Wheeze Treatment Freestyle!)  Surely the whole point is to avoid giving steroid inhalers when the diagnosis is viral wheeze.  Well, as is often the case, yes and no.  Yes, most of the time but no, not always.

The vast majority of children who only get wheeze during a viral illness will do so relatively infrequently.  Also, the episodes in most cases will be mild or moderate and (more importantly) respond well to decent doses of bronchodilators.  The key differences between these children and the smaller number of children who have an atopic cause to their wheeze are that preventative steroid inhalers are not at all likely to prevent or blunt exacerbations of viral wheeze, and the evidence is that systemic steroids do not work for acute episodes.

However, not all viral wheezers were created equally.  Some get frequent exacerbations and some get frequent and severe exacerbations.  There is much debate about phenotypes, genotypes and other big words that don't mean much to the poor three year old who is getting the symptoms.  There is genuine uncertainty about whether there are multiple entities or overlaps and polymorphism.  My  hope is that the paediatric respiratory world find a way to identify the subgroups without over-complicating the list of possible diagnoses.

What we have at the moment is two main groups, with the more severe end of the viral wheeze group being treated in ways that look remarkably similar to the asthma group.  Similar, but not the same.

With the child under five who has an asthma pattern of wheezing, steroid preventer inhalers are a cornerstone of management.  If the diagnosis is recurrent viral wheeze, steroid inhalers are an option when exacerbations are very frequent, especially if severe.  The current advice is that a trial of steroid inhalers should be evaluated and should be stopped if not helpful.  How one knows whether the trial has worked is another question.  If anyone knows a cast iron way of deciding this please get in touch or post a comment.

Edward Snelson
@sailordoctor

Disclaimer: I am not a Respiratory Paediatrician, but sometimes I see so many children with wheeze, it feels like I should be.