One of my fundamental thoughts about the diagnostic model in medicine is illustrated by this case from the week's NEJM titled The Deficient Diagnosis. The authors' comment in the closing paragraph on "circuitous diagnostic route" could (should) be applied to many other clinical situations. That is, most diagnostic routes, except the very obvious are indeed circuitous. And it is this aspect of medical decision refinement that should (or so I think) eliminate the term "errors" from the mix.
Instructive, especially to us, is the child's prior presentation, and the ultimate necessity of coming through the ED to find the true path to a successful diagnostic "route."
Were there errors prior to acquisition of a clinically actionable entity? I don't see them that way. Or maybe "hell no!" This is the nature of medicine, in general.
Compare to someone who arrives with chest pain and acute ST-T elevation. A no-brainer, so to speak. But throw into the mix someone whose EKG and two enzyme sets are normal, scheduled for a stress-test in 72 hours, and dies of an acute MI in 40 hours. Error? I don't see it that way. Safe-route? Not for that patient.
So diagnosis is not static, but dynamic. Even in the NEJM case, once action ability is reached, is that the "final" diagnosis ? (Of course "final diagnosis" is a term we use but applies in most cases to the moment of discharge, highlighting its inherent temporal nature) . How many times have diagnostic pathways forced our otherwise non-compliant minds into submission to diagnosis' dynamism? Take hypoglycemia --> poor insulin administration --> (wait) Addison's disease --> (wait again) Multiple endocrine adenopathy. Or chest pain --> acute MI --> aortic dissection. And on and on.
Diagnosis is not, and should not ever be, a static entity. What are called "errors" therefore are indeed (expected?) steps off the fastest route. (That route of course is faster if the patient comes to the ED !!). I think it would serve the diagnostic error community (if there is one) well, and the emergency medicine community (to which we belong) well if this were better encountered theoretically. Hence, if done, a path to actionable diagnosis is best served when the time-frame to it is the shortest possible. And the ED is the best site for that !!