Thursday, 25 August 2016

Hunting the focus of infection

Finding a focus for infection in a child is one of those things that we all know we ‘must do’.  That can be more difficult than it sounds.  Often, no focus is easily found and then the questions are, “Where do I look?  What if I can't find a focus?  I don’t know when to stop looking!”

How many children are seen with significant temperatures, where the eardrum is not easily seen?   On probability alone, the focus is more likely to be a hidden upper respiratory tract infection rather than something else.  Is probability enough to go on? 

Then there are the things that could be called a focus, but are rather soft signs.  Is a runny nose a focus?  If so, how high is the temperature allowed to be?  What about vomiting and diarrhoea?  Is that a focus in its own right?  You could throw that question out to an audience of primary and secondary care clinicians and I could guarantee that the conversation (if it continued in a way that could be called that) would go on for quite some time.  The outcome would almost certainly be that many would agree to disagree.


If you ask me, the answer depends entirely on the circumstances because the focus of infection is not nearly so important as the global assessment and the specifics of the presentation.  If a child presents early in an illness, is relatively well and has just got a runny nose, then that might be enough to go on.  Good symptom management and careful safety netting are probably the most important things in these cases.

Example 1
A 3 year old has a temperature of 38.2 at home.  They have a runny nose and a cough but no other symptoms.  They have no convincing focus of infection in their throat or ears.  Chest is clear and there is no respiratory distress.  Heart and respiratory rate are normal.  During the consultation, they are running around and playing with the toys.

Example 2
A 3 year old has had a temperature of 38 to 39 on and off for three days.  They have a runny nose and a cough but no other symptoms.  They have no convincing focus of infection in their throat or ears.  Chest is clear and there is no respiratory distress.  Heart and respiratory rate are normal.  They are alert but neither cheerful nor very active.  They have just returned from a three week trip to an area where malaria is endemic.

Who would like to accept the runny nose and cough as a focus in child 2?



So when do I need to find a focus?  Here are a few examples of circumstances in which I would want to have something that is fairly definitive:


My two top tips for finding a focus are:

  1. Repeat the ENT examination unless you have already had really good views of tympanic membranes and pharynx
  2. Check a clean catch urine sample

When deciding about how hard to look and how invasive the search should be, don't start at the beginning, start at the end.  The child in front of you and the clinical scenario determine what the hunt will involve.

Edward Snelson
Variable Venator
@sailordoctor


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