Law of Unintended Consequences

You’ve probably all heard of the Law of Unintended Consequences.  It even has a page on Wikipedia. In short, it says that things that you do may have results that you did not intend.  Of course these can be unexpected windfalls as well as other, more unfortunate side-effects.  There is also limited benefit to saying “think about the consequences of your actions” because obviously – 1) people don’t and 2) there may well always be unforeseeable unintended consequences.

But there are a couple of pretty straight-forward examples where a very limited amount of thought would prevent quite a significant knock-on effect.  Of course, this knock-on may well create work for someone else, so you probably don’t care all that much.

Imagine you are a doctor.  (Some of you may have to work harder than others).

Imagine a parent brings a child to you with spots.

You’ve never seen a case of measles – because it’s almost been eradicated from Australia.  I’ve only seen one actual case, and I’m an infection specialist (although I’m in my 30s – older GPs have probably seen a bit).

Measles cases in Australia

Measles cases in Australia

Here you have a couple of choices.

1) You could explain that you’ve never seen a case of measles, so you’re not sure if is or not.  You could do some tests and send them home, letting the mum know you’ll tell her when the test results come through.

2) You could call someone who might have more experience to ask for advice.

3) You could confidently declare that it’s measles and tell the child’s parent to keep them home from school so they don’t cause any secondary cases – after all, that’s what it says to do in the Time Out guidelines.

Option 3 happens surprisingly often.

So let’s look at some of the unintended consequences.

  • The mum goes home and wikis Measles – and becomes rather anxious that the article says it used to have a 30% mortality.  She also clicks on Subacute Sclerosing Panencephalitis – and gets a bit worried that her child has an illness that can cause a progressive incurable brain disease
  • The mum helpfully rings the school principle who then anxiously calls the public health unit wanting to know why they weren’t notified directly and should they notify parents and OH MY GOD THE ANXIETY!
  • The mum also tells her friend who tells their friends who tells someone else who works for the local rag which precipitates an email like this:

“Hi, I’m a journalist from the Local Rag and we have reason to believe there are cases of Measles at Local School.  Can you please provide information on this as we intend to run the story on tomorrow’s front page. Our deadline is 4pm”

  • One of mum’s other friends is a conscientious objector to vaccinations and then either presents to the local hospital or rings the public health unit requesting prophylactic immunoglobulin because her child (Storm or Phoenix) isn’t vaccinated and urgently needs less effective and more risky post-exposure treatment because they aren’t immunised.

The mum rings the public health unit to try and address all her questions about the diagnosis of measles.  The public health staff start asking the mum a few questions and explain to her that:

  • There isn’t actually any definite evidence that the case is measles because no testing was done.
  • Some directed questioning reveals that the child almost certainly doesn’t have measles because
    • The child has had two doses of MMR and is almost certain to be immune to measles
    • There have been no cases of measles in the local area in the past few weeks
    • The child and its family have not traveled outside the area and have had no contact at all with anyone who was sick
    • The illness doesn’t actually meet the case definition for measles which is quite specific – rash, fever present at the time the rash comes on and one of (cough, runny nose, conjunctivitis or Koplik spots).
  • This precipitates a round of “but my doctor said…” in which public health staff have to politely and subtly point out that the doctor probably got it wrong while being mindful that they haven’t actually seen the patient and also of professional courtesy

The rest of the day is spent in arranging appropriate testing, reassuring the school principle, drafting a media release explaining that there isn’t measles anywhere and filling in a mountain of paperwork.

Contrast this with:   Admitting you don’t know what it is, looking up the guidelines and doing some appropriate tests, calling public health and letting them sort it out tomorrow.

Let’s be clear:

  • Measles is a rare disease in Australia (although sadly not so rare as it used to be)
  • You probably haven’t actually seen an actual case unless you’ve been in clinical practice for many years
  • There are many causes of morbiliform rashes – and the pre-test probability of it being anything other than measles is quite high.
  • If the child is fully vaccinated, measles is quite unlikely (but not impossible)
  • If the child has been given antibiotics in the past week, consider that it might be a drug eruption.

I hear you saying “that’s all specific public health / infectious diseases knowledge, surely it’s not my job to know that”.  This is quite true, it isn’t really.

But just yesterday, you thought that your knowledge was sufficient to diagnose a rare disease that you’d never seen without any tests, recommend a management plan based on these feelings (which was actually wrong, by the way) and failed to notify your suspicions in accordance with the public health act.  You can’t have it both ways.

The man who admits his ignorance shows it once. The man who conceals it shows it many times


Don’t be such a fucking muppet.

~ by Trent on October 28, 2013.

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