1/The base rate…a double-edged sword.
A mini-tweetorial on this crucial concept in clinical reasoning.
A mini-tweetorial on this crucial concept in clinical reasoning.
2/What is it?
The base rate is the relative frequency of a diagnosis within a clinical context.
Example:
In the emergency room, what % of patients with dyspnea have a pulmonary embolism?
The base rate is the relative frequency of a diagnosis within a clinical context.
Example:
In the emergency room, what % of patients with dyspnea have a pulmonary embolism?
3/
What’s the deal with the clinical context?
The base rate is function of the clinical syndrome being considered.
The frequency of a disease in an incompatible clinical syndromes is close to zero.
Example:
The rate of PE in patients with acute dysuria is nearly zero.
What’s the deal with the clinical context?
The base rate is function of the clinical syndrome being considered.
The frequency of a disease in an incompatible clinical syndromes is close to zero.
Example:
The rate of PE in patients with acute dysuria is nearly zero.
4/
Why is it important?
Pathophysiology repeats itself...
The most powerful variable that determines the likelihood of a diagnosis?
The list of diagnoses in the last 1000 patients with the same issue.
Why is it important?
Pathophysiology repeats itself...
The most powerful variable that determines the likelihood of a diagnosis?
The list of diagnoses in the last 1000 patients with the same issue.
5/
This is why we have a dyspnea pyramid.
It’s should take a lot of work to move past the cardiopulmonary base, in part because of how common these lung and heart issues are.
(Morbidity of the Dx also plays a big role...more on that next time)
This is why we have a dyspnea pyramid.
It’s should take a lot of work to move past the cardiopulmonary base, in part because of how common these lung and heart issues are.
(Morbidity of the Dx also plays a big role...more on that next time)
6/
Don’t drop the anchor too quickly though…
Just because something is common doesn’t make it the diagnosis.
Don’t drop the anchor too quickly though…
Just because something is common doesn’t make it the diagnosis.
7/
Is all painless jaundice + pancreatic mass = pancreatic adenoCA?
Check out this incredible case by @DxRxEdu for more (and the final Dx!)
bit.ly/2OPd76H
Is all painless jaundice + pancreatic mass = pancreatic adenoCA?
Check out this incredible case by @DxRxEdu for more (and the final Dx!)
bit.ly/2OPd76H
8/To summarize:
The base rate is a fundamental component of clinical reasoning and is the most effective route towards the Dx.
Remember, though, it never takes us all the way home.
The base rate is a fundamental component of clinical reasoning and is the most effective route towards the Dx.
Remember, though, it never takes us all the way home.
