If I told you that it was day 6 of the illness and that for the past 3 days the child was neither better nor worse would you think that the diagnosis was likely to be acute sepsis? No, but can we get a guideline to help us get there?
Since it is a factor in our decision making, we could add in the dimension of time and disease progression to our guideline. If we did that I think that it could look something like this:
Even adding this dimension doesn’t fulfil our need for something which maps to our way of thinking. We now have the bit that focuses on the child in front of us and the bit that takes into account the real world where patients present in different ways, but many guidelines fail to take into account the fact that different diseases behave differently. Worse than that, the differences can be subtle.
Guidelines often struggle to deal with the fact that medicine is a complicated subject. Do you write a guideline for a clinical scenario (e.g. a febrile child)? If so, you need to include every possible cause and when to think of it. Do you write your guideline about a specific disease (e.g. Kawasaki disease)? If so, how will people know when to use the guideline? If they have looked it up, they are 90% of the way there and the guideline is going to be more useful as confirmation and treatment advice.