Bottom Line: The phrase “until proven otherwise” is really overused.
This is just a brief rant about a phrase that drives me nuts. In medicine, there are numerous conditions that can either worsen suddenly or are otherwise time-critical. In describing management for a patient in which such a condition is being considered, it’s common to hear that one should take reasonable steps in their care as if that diagnosis had been made. This often involves the phrase “until proven otherwise.” When a 62 year old male presents with chest tightness, diaphoresis, shortness of breath, and left arm and jaw discomfort, that is ACS until proven otherwise.
It’s often an effective way to make a point; when some lecturer looks you in the eye and sternly insists, “When you see x [lab or exam sign, symptom, finding on imaging], it is y until proven otherwise!” people tend to listen, and often remember. But therein lies the problem: I can’t imagine a better way to convince learners to narrow their differential diagnoses prematurely. In my (very limited) experience observing people that like to use the phrase, it seems that it is very rarely a highly specific “x” for condition “y.” Even a slight semantic modification, “x should be managed as y,” would be an improvement, reminding people that this is usually an issue of urgency, not of likelihood.
The other problem with it being such an effective, formidable phrase is that it’s not necessarily a sound recommendation, and it’s difficult to rebut. “A patient with the sniffles has a pulmonary embolus until proven otherwise!” With that admonition, do you:
- do your d-dimer, PERC rules, V/Q scans, and tri-phase helical 64 slice CTs on every patient with the sniffles?
- fail to rule out a life-threatening condition on sniffling patients?
- stammer out a response to the misguided (but likely well-intentioned) teacher, something along the lines of “Ummm, I don’t think that’s actually true…”
Except that it’s not really a falsifiable statement, because it includes both conditions (“the patient has this unless they don’t”). And it’s not really advice… just a statement, present indicative, and a pretty vacuous one when you think about it. In spite of that fact, you’ll hear it echo down the hospital corridor a few times each day, making sure some skeptically disinclined soul sleeps more soundly after ruling out or treating a diagnosis that only merited consideration.