Monday, 19 December 2016

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.

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