If it Looks Like a Duck…

My reading of ‘Thinking Fast and Slow’ (Daniel Kahneman) for our monthly book club, brought to mind the dangers of over reliance on our common medical rules of thumb and the making of spot diagnoses.

On the one hand, the very name of the disease or syndrome immediately brings to mind important details and standard treatment recommendations of that disease or syndrome, thus increasing the efficiency and success of the management of the disease.

However on the other hand, these rules of thumb can delay us from looking beyond the lines, outside the box and thinking laterally.

Automatic fast thinking and the making of a spot diagnosis, may have been a factor in the recent death of a young man in his thirties. He was presented to Emergency with sudden onset severe chest pain, and so was immediately and intuitively labelled as having a coronary infarction. Appropriate coronary treatment was started but repeated cardiac enzymes and EKGs were normal. The time taken for these may have delayed the Emergency team from noting some features Marfan’s and considering a possible aneurysm. So when the simple but delayed AP chest x-ray revealed a dissecting aortic aneurysm, the narrow time window for surgical repair was closed and he died, indeed the likely outcome even if the aneurysm was spot diagnosed on arrival.

The ability, to make intuitive diagnoses based on rapid rule of thumb fast thinking, is an important skill of the Emergency team and we all know the old adage:

“If it walks like a duck……….”


-Anthony Dwyer, M.D.

(The opinions stated in this blog are those of the author Dr. Anthony Dwyer and not necessarily those of the American College of Spine Surgery).


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