The speed of onset of a condition can be crucial in forming a differential diagnosis.
Example to work through
A classic example of the importance of emergence speed is a subarachnoid hemorrhage from a cerebral aneurysm, typically described as the “worst headache of my life” and having sudden onset in a few minutes.
On the Start screen one can specify emergence over 10 minutes:
Specifying this timing, and adding the finding of headache using the green search icon on the top black navigation bar and clicking “Go to Dx” gives a differential diagnosis including headaches with sudden onset: (Registered users can click the images below to jump into the software; some videos may be helpful in navigating from there)
Going back to the Start screen by clicking Start on the top black navigation bar and specifying onset instead over 10 months and then clicking Dx on the top black navigation bar gives a very different differential diagnosis:
Neglecting speed information can lead to misdiagnosis and missing of situations in which emergency intervention is warranted.
This page is part of a series on the Elements of Diagnosis.
Copyright © 2025 SimulConsult