Your New Year's Resolution - Undiagnose a Child This Year

If you’re wondering what to do for your New Year’s resolution, don’t give something up or join a gym.  Neither will work out anyway.  This year, do something truly worthwhile - promise yourself that you will undiagnose a child or three.

Paediatrics is particularly prone to the pitfalls of overdiagnosis and overtreatment.  Although this is a problem, the reasons for overdiagnosis are actually good ones:

• The tendency for symptoms to resolve with time (e.g. vomiting and crying in infancy)
• In childhood there is usually an illness that can’t be treated which mimics those that should be taken more seriously (e.g. viral urticaria leading to overdiagnosis of antibiotic allergy)

When there are no good tests available to tell between two possibilities, we sometimes give a therapeutic trial to help answer the question.  That is a strategy which will lead to misdiagnosis if symptoms improve despite our treatment rather than because of it.

With therapeutic trials, it is often best to challenge the assumption that it was the treatment that worked.   The two best examples that I can think of are childhood asthma and cow’s milk protein allergy in infants.

Let me give you a case to illustrate what I mean:

A 3 month old has been treated unsuccessfully for symptoms of gastro-oesophageal reflux disease (GORD).  A clinician suspects non-IgE Cow’s Milk Protein Allergy (CMPA) because first and second line treatment for GORD has been unsuccessful and because they notice that the baby has quite significant eczema.  (Click here to see a guide to diagnosing feeding problems in this age group)  The clinician decides to trial an extensively hydrolysed feed.  Over the next few weeks, the child’s symptoms of being unsettled and bringing back feeds improve considerably.  The eczema is responding to topical treatment.

In this situation, it is easy to assume that the change of milk was what made the difference.  Often, this is simply confirmation bias.  Colic, reflux and other symptoms of infancy have a tendency to self-resolve.  Of course the treatment may have been what worked but at this point in time, we genuinely have no idea.

This is the time to stop the hydrolysed formula and reintroduce a standard formula.  (Only do this for Non-IgE CMPA.  IgE CMPA is the kind that has urticaria and wheeze etc.  The children with this type of allergy need to be referred to an allergoligist.)   If the original symptoms of being unsettled and vomiting lots return in the next couple of weeks, the diagnosis is now more robust.  If the child remains well despite a return to standard formula, you have undiagnosed a thing.  Marvellous.

The second clinical scenario is the 7 year old with a nuisance cough.  The cough has been there for somewhere around 2-3 months.   There are no associated symptoms such as wheeze or altered exercise tolerance, but the cough is waking the family up at night.  The chest is clear on examination.

So, what is the likely diagnosis?  Surprisingly, in research land, coughs like this turn out to be caused by pertussis infection more often than asthma or reflux disease. (1,2)  It seems that although the pertussis vaccination is successful, infection is still relatively common.  Instead of causing a more significant respiratory illness, what we see in vaccinated children is often just the cough that lasts 100 days.  There are other, similarly benign reasons for chronic cough in children.  Also, there are plenty of significant pathological causes of chronic cough that are not asthma.

Diagnosing ‘cough variant asthma’ is possibly the biggest reason for the current debate about overdiagnosis of asthma in children, fuelled by an article in the BJGP earlier this year. (3)   Many children in the UK are prescribed inhaled steroids for chronic cough symptoms.  If they get better, this is taken as evidence that they had asthma, but there are other possible reasons for this resolution of symptoms.  The evidence suggests that the most likely thing is that the cough has resolved with time rather than with treatment.

This is therefore another opportunity to undiagnose a thing.  As well as stopping inhaled steroids after (Snelson makes up a number quickly…) three months it is probably a good idea to get some sort of objective assessment before, during and after the therapeutic trial.  Peak flows are great if you can get the child to do these well.  In many cases a symptom score (4) is more achievable.  If the only complaint was cough, then a symptom diary is all that is required.

If when you stop the steroids, the child’s cough is still resolved, you have a winner.  Your New Year's resolution is fulfilled.  Of course, once you start, undiagnosing an become a bit addictive.  If you find it becomes a problem, why not join a gym instead?

Edward Snelson
Diagnosectomist
@sailordoctor

Disclaimer: My New Year's resolution is to get a better disclaimer.

References:

1. Marchmont et al, Evaluation and Outcome of Young Children With Chronic Cough, Chest Journal, May 2006, Vol 129, No. 5
2. Wang et al, Whooping cough in school age children presenting with persistent cough in UK primary care after introduction of the preschool pertussis booster vaccination: prospective cohort study, BMJ, 2014;348:g3668
3. Looijmans-van den Akker et Al, Overdiagnosis of asthma in children in primary care: a retrospective analysis, BJGP, 1 March 2016
4. Asthma.com, Child Asthma Control Test

If you can't decide between turkey and goose... Pertussiolitis and other animals - when a child has noisy breathing

Recently I learned a good way to find the answer to a question.  It happened like this-

On a walk in Sheffield I saw this strange bird:

Unable to find this creature described in a ‘Birds of Britain’ book, I posted the picture to Facebook and commented that (to me) it looked like a cross between a turkey and a goose.  Most other Facebookers were similarly unfamiliar with the species but within a short period of time, I received a response from my niece who declared the bird to be a Muscovy duck.  After quickly confirming this to be true, I asked how she recognised this bird which is not native to the UK.  The response that came back was simply that she had searched the internet for "birds which look like a cross between a turkey and a goose". 

Boom.

I had the chance to complete this lesson, for myself in a clinical context, shortly afterwards when faced with another unfamiliar animal, this time in the form of a baby with an ambiguous presentation.  The child had developed a cough and feeding difficulties and had now become wheezy.  Preemptively, my diagnostic centres had skipped forward to the disease that I thought I merely needed to confirm: bronchiolitis.   This mental process was interrupted by a cough from the child, and what a cough it was.  It went on and on and on…  At the end of the period of coughing, the child’s face was properly red. The mother informed me that more often than not a spectacular vomit followed these paroxysms of cough.

With the new possibility of whooping cough suggesting itself, I examined the child with a new mission: confirm findings that are consistent with pertussis infection.  I was therefore, properly annoyed to find a wheeze which I felt was more in keeping with bronchiolitis.  Faced with this puzzle and remembering my niece’s methods, I asked the internet and found that, while not a typical feature of pertussis infection, wheeze has been well described in a large number of cases of children with whooping cough. (1)

This case reminded that, as primary care clinicians, we don’t really diagnose infections- we diagnose syndromes.  Bronchiolitis, for example, is not RSV infection.  Bronchiolitis is a syndrome of wheeze, poor feeding and cough which can lead to severe respiratory distress, apnoea and feeding or respiratory failure.  RSV is one possible cause amongst many untreatable viruses.

Similarly, despite what I was once taught, croup is not caused by parainfluenza virus.  Any virus can cause the upper airway swelling that leads to barking cough, possibly stridor and varying degrees of respiratory distress.

Just to keep me on my toes, children seen to present from time to time with features of multiple syndromes.  The most common bedfellows are croup and viral induced wheeze.  When faced with a child who has a barking cough and a wheeze, one initially questions whether the noise is in fact a stridor (and rightly so).  If it is a wheeze, then it is a wheeze.  If the child has both croup and viral induced wheeze, ther is no point trying to limit the diagnosis.  Just get on and treat both.  It occasionally causes a bit of confusion if the child needs admission.  I think that some junior doctors take the referral of a child with the diagnosis of viral wheeze and croup together to be a sign of uncertainty, or perhaps dementia.

I would suggest that perhaps wheeze is not a feature of whooping cough but that it is possible for a baby to have bronchiolitis at the same time as whooping cough, both caused by pertussis infection.  It doesn't really matter though, since the cause of the infection is only of interest if it can be treated, or transmission prevented.

There are so many infectious causes of noisy breathing in children. Here is a simple guide to what’s what and what to do about it:

Many thanks to my niece for teaching me what the internet is for.

Edward Snelson
Ornithopathologist
@sailordoctor

Disclaimer: I take full credit for inventing the use of evidence based medicine in the consulting room.

Reference:

1. Taylor Z.W. et al, Wheezing in children with pertussis associated with delayed pertussis diagnosis, Pediatr Infect Dis J. 2014 Apr;33(4):351-4.

Acknowledgement: This is a slightly different version of a post which I wrote for the Network Locum Blog earlier this year.

Coughing children - Persistent, Perplexing or Paradoxical? Probably not asthma!

In the previous post, I gave a little guidance about patterns of cough in children.  Now, I'll add a little probability to the mix.  After all, good medicine relies heavily on knowing the likelihood of a given disease in a particular scenario.

As someone who occasionally mentions medi-facts that came from articles that I have long since lost track of, I was pleased to be able to re-find an article from Chest (the journal of the American College of Chest Physicians) that I have been using in both practice and teaching.  It asked the question, In persistent cough, can we extrapolate an adult based approach to be used in children? (1)

The resounding answer was no.

Once again, children are shown not to be mini-adults.  Paediatricians everywhere breathe a sigh of relief...

What is perhaps surprising is the number of children with a persistent cough who have evidence that pertussis is the culprit.  In several studies now, the proportion has been shown to about 20-40 % of children who have been coughing for more than two or three weeks.  That large number includes studies that have been done since the ramping up of vaccination campaigns. (2)

Pertussis is a significant illness which still has a mortality of around 3% in unvaccinated babies.  Although less of a menace since the introduction and later improvement of vaccination programs, pertussis is still endemic.  It should be suspected whenever a baby presents with an acute cough.  The typical cough is paroxysmal and there are features that often make the diagnosis more obvious.  Some children get the classic 'whoop' at the end of a coughing paroxysm while some will vomit or have (hopefully brief) apnoeas. It seems from the studies into persistent cough that not all pertussis is obvious acutely.   Early detection reduces both symptoms and transmission.  Guidance on this from the Public Health England can be found here.

So, before thinking that a persistent cough in the absence of wheeze might be asthma think: 'Could this be pertussis?'  The advantages of this are:

1. There is no test for asthma.  There is a test for pertussis.
2. As well as diagnosing the index case, you may help to identify the cause of other persistent coughs that are troubling the family and friend of this little one.
3. You may save a life.  If the pertussis is passed onto (for example) a new born baby this could be devastating.  By recognising pertussis you may prevent transmission.
4. You avoid the trap of confirmation bias.  If you are tempted to 'try' an inhaler for a few weeks, you may be tricked into believing that it helped when the cough gradually resolves, as it should in time with post-pertussive cough.

Edward Snelson
@sailordoctor

Disclaimer: Of course if we're going to talk probabilities, it's probably a virus...

https://www.facebook.com/PaedsTips

References

1. Marchmont et al, Evaluation and Outcome of Young Children With Chronic Cough, Chest Journal, May 2006, Vol 129, No. 5
2. Wang et al, Whooping cough in school age children presenting with persistent cough in UK primary care after introduction of the preschool pertussis booster vaccination: prospective cohort study, BMJ, 2014;348:g3668
3. Public Health England, Pertussis factsheet for healthcare professionals

Better FOAM - are you getting the picture? (Easter egg - persistent cough in children)

I have an apology to make.  When I wrote about how to tell the difference between bronchiolitis and viral induced wheeze, I talked too much.  I know this thanks to a wonderful audience of GPs who are attending a series of paediatric masterclasses here in Sheffield.  When I described the way to use the prodrome of the illness (as described in the post linked above) I could tell from the faces in the audience that my explanation hadn't yet hit the mark.  Then I put up this slide:

This, coupled with a description of the presenting complaint* for the two conditions seemed to work and I'd like to think that everyone then understood what I was saying.
* With bronchiolitis, the parent usually describes a day by day gradual worsening of the symptoms; with viral wheeze the child often goes from snotty to very wheezy over the space of a few hours.

Pictures, coupled with explanations are a powerful tool for teaching.  I don't have the time to make pictures as much as I would like to, but I will try to do so more often.  Thankfully I learned my lesson just in time, as I was going to write about children who present with persistent cough this week.  Once again, pictures will be needed.  Here I go:

Persistent or Chronic Cough in Children

Children are often brought to GPs and EDs with a cough as the primary symptom.  It is not uncommon for the cough to be reported as having been there for weeks or months.  These histories of protracted coughs tend to cause a variety of responses including a mixture of scepticism and anxiety.  My initial thought of, 'Has this child really been coughing for weeks?' is followed by 'Could it be tuberculosis?'  Both responses are valid.

There are essentially four groups of cough that are present over the space of weeks or months.  The first and most common of these is the cough that comes and goes.  These children are almost invariably having repeated viral upper respiratory tract infections (URTI).  For this reason, the first task is to establish whether the cough ever resolves, leaving periods of normality, however brief.

The second group is those that have a dry but persistent cough that never seems to get worse but never goes away.  In the absence of any red flags (see below) or other clues, this may be normal.  About one in five children (1) are reported to have a daily cough.  Most have no underlying abnormality.  Some have a behavioural element or a relatively benign cause such as post-nasal drip.

The third group is the slowly resolving cough.  Coughs often persist for weeks after an infection has gone.  Even following a simple viral URTI, a large proportion of children cough for weeks afterwards.  Sometimes, such as with bronchiolitis or pertussis, the cough takes even longer.  (2) The important thing is to establish whether the cough is resolving, however slowly.

The final group is the one to watch out for.  If the cough is getting worse, and lasts for more than eight weeks and is getting worse then the likelihood of pathology is much higher.  Most children will present well before eight weeks, so a single course of broad spectrum antibiotics will usually have been tried.  If the cough is getting worse despite this or there are other red flags, the child should be referred.

The red flags that suggest that referral is needed are fairly intuitive:

Where a benign cause is suspected, then treatment can be directed accordingly:

In all cases, smoking cessation is likely to help.

Suspected infection - if there has been a temporary improvement from antibiotics and the child has a chronic wet cough, this may need a longer course (e.g. two weeks) of a second line antibiotic (e.g. Co-amoxiclav)

Post nasal drip - steroid nasal spray/ antihistamines

Behavioural - reassure and advise to distract the child.  The family must avoid any reinforcing behaviours of their own.

One thing that is not recommended is a trial of systemic steroids in chronic cough.(3)  Cough as an isolated symptom, without any wheeze or other indication is very unlikely to be due to asthma.  Steroids may however, mask a mediastinal lymphoma in rare cases.

Symptomatic treatment of the cough is also best avoided.  There are no effective cough remedies in children that do not have significant adverse effects.

So, when a child presents and you are told that the cough has been going on for 6-8 weeks that doesn't mean a lot without the pattern of cough and associated features.

In most cases no treatment is needed.  If explaining that doesn't go down well with the parent, instead of prescribing something anyway, why not draw them a picture?

Edward Snelson
Head of the Sheffield Medical Artists Consortium
@sailordoctor

References

1. J C de Jongste, M D Shields,  Chronic cough in children, Thorax 2003;58:998-1003 doi:10.1136/thorax.58.11.998
2. Thompson, M, Duration of symptoms of respiratory tract infections in children: systematic review, BMJ 2013;347:f7027
3. Chang, A, "Isolated cough: probably not asthma" Arch Dis Child. 1999 Mar; 80(3): 211–213