week 3

Question 1

differential diagnosis

Answer 1

-the process by which clinicians consider some possible causes of the patients signs and symptoms before making a final diagnosis
-after obtaining some information from the patient, compare this information to ones understanding of different conditions to generate multiple hypotheses about what might be going on
-if not done deliberately, people tend to fail to consider options before arriving at an initial guess

Question 2

errors- going with the first guess

Answer 2

-don’t just go with first guess
-the most common conditions are not typically the most serious and the consequences of missing a serious diagnosis are higher
-inital guesses are particularly subject to the availability heuristic
–> i.e. tendency to use information that comes to mind quickly and easily
–>favours recent or more memorable experiences

Question 3

what is the availability heuristic

Answer 3

–> i.e. tendency to use information that comes to mind quickly and easily
–>favours recent or more memorable experiences

Question 4

what is possibilism

Answer 4

make a list of all possibilities

Question 5

errors- making a list of all possibilities

Answer 5

-aka possibilism
-technically impossible
-takes a long time and tends to be a confusingly long list without the extra possibilities adding value
-can lead to unnecessary testing/ diagnostic work-up
-people sometimes use mnemonics as frameworks for generating differentials (i.e. VINDICATE; vascular, infections, neoplastic…) but even these tend to lead to excessively long lists
-ultimately, you can add differentials later anyway if they become more reasonable to consider

Question 6

what are the 3 Ps

Answer 6

probability: what is most likely?
prognosis: “must-not-miss” conditions - which conditions are worst if left unconsidered
pragmatism- what conditions have the best benefit:harm ratio if treated

Question 7

when to start considering

Answer 7

-generally done after gathering a bit of information about the chief concern
-if you start too early, the list will tend to be pointlessly long
-will let you work with a more holistic sense of the patient’s concern
-will allow you to better compare it with your disease illness scripts
-you will update this list later as more information becomes available

Question 8

problem list –> processed problem list –> patient illness script

Answer 8

patient illness script:
-epidemiology
-timing
-syndrome statement
-other history

Question 9

what errors do beginners make

Answer 9

-beginners may create excessively long or extremely short lists based on misconceptions about medical diagnosis (i.e. “possiblism” and/or insufficient compensation for the availability heuristic)

Question 10

what’s the purpose of differential diagnosis

Answer 10

-allows for the possibility that the initial beliefs about the diagnosis were incorrect, facilitating better decision-making
-differential diagnosis is aided by appropriate problem representation