Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Objectives
By the end of this module, you should be comfortable:
•
Given a chief-complaint, create a list of differential diagnoses of life threatening
conditions.
Understand how to use diagnostic testing properly, using your pretest probability
•
Preparatory Work
Before continuing, read, listen and watch the following:
•
•
•
•
•
•
•
The Approach to the Emergency Department Patient
Diagnostic Testing
Chest Pain CDEM
ACS CDEM
TAD CDEM
PE CDEM
Pneumothorax CDEM
Complete this module prior to your first day (orientation). We’ll go over it then. Don’t worry
about being right, we just want to get the brain juices flowing.
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Case Presentation:
A 57 year-old male presents with a chief complaint of chest pain. His triage vitals
signs are:
BP: 120/80, HR 95, T 98, R 15, O2 sat 100%.
You see them wheel him to the room and he appears uncomfortable, diaphoretic and
ashen colored.
One of the keys to functioning well during your Emergency Medicine rotation is the ability to
make a good differential diagnosis. This differential will guide your history, physical and
management.
The differential is not made at the bedside or even as you’re walking to the room. It is made
ahead of time. This is driven by the chief-complaint. This complaint is not necessarily what’s
written on the chart (like the young man embarrassed to tell the female triage nurse about rectal
pain instead claims abdominal pain), but the triage note is a good place to start.
With each chief-complaint come up with at least 5 things that can kill someone presenting as
such. There are often more than five, but for this exercise come up with at least five bad things
which can present as chest pain. Hint: acid reflux is not one.
1
2
3
4
5
6
7
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Case Presentation:
A 72 year-old female presents with a chief complaint of shortness of breath. Her
triage vitals signs are:
BP: 120/80, HR 95, T 101.2 R 24, O2 sat 89%.
You see them wheel her to the room and he appears uncomfortable, diaphoretic and in
distress.
Let’s do this again, this time with shortness of breath. In addition to the chief-complaint, the
vital signs can also inform your differential diagnosis. These are the first pieces of information
you have: chief-complaint, age, gender and vital signs.
With the chief-complaint of shortness of breath, come up with at least 5 things that can kill
someone presenting as such.
1
2
3
4
5
6
7
How do the vital signs affect your differential diagnosis?
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Case Presentation:
A 32 year-old female presents with a chief complaint of abdominal pain. Her triage
vitals signs are:
BP: 120/80, HR 95, T 98 R 20, O2 sat 98%.
You see them wheel her to the room and he appears uncomfortable, but speaking
appropriately.
Let’s do this again, this time with abdominal pain. Come up with at least 5 threats to life or limb
presenting as such.
1
2
3
4
5
6
7
Gender also plays a role. This list will be different if the patient were a man.
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Case Presentation:
A 22 year-old male presents with a chief complaint of sore throat. His triage vitals
signs are:
BP: 120/80, HR 95, T 100.8, R 15, O2 sat 100%.
Now let’s pick a less obviously severe diagnosis. Again, you should look at only the chief
complaint, age and vital signs and come up with a differential diagnosis of potential threats to
life and limb.
Come up with at least five bad things that can present with sore throat. Hint: strep throat and
viral syndrome are not on the list.
1
2
3
4
5
6
7
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Using your Differential to Guide your Evaluation
This differential diagnosis is the crux of our entire process. You’ll use this to determine which
questions to ask, what to look for on the physical exam and also what tests you’ll need to order.
Pick one of the differentials you created above (or make a new list) and make a list of historical
factors that would increase your suspicion for that disease (in the row with a plus). Next make a
list of things that would decrease your suspicion (in the row with a minus). Do the same with
your physical exam.
Complaint:
Diagnosis
History
Physical
+
+
-
-
+
+
-
-
+
+
-
-
+
+
-
-
+
+
-
-
+
+
-
-
+
+
-
-
1
2
3
4
5
6
7
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Pretest probabilities & Test Interpretation
Now you will use those features which increase or decrease your suspicion to
assign a probability to that diagnosis. How likely do you think the diagnosis is?
High? Medium? Low? No-way? Determining this pretest probability is
important for a couple of reasons:
All tests will be interpreted in light of this. You will interpret the same normal
EKG differently in the patient with crushing sub-sternal chest pain, diaphoretic,
sweaty, short of breath and pain just like his last 10 heart attacks versus the 18
year old eating a bag of Flaming Hot Cheetos. This same EKG means different
things in 2 different patients.
Listen to David Newman talk about Diagnostic Testing (from SMART EM) from his podcast.
He’s a brilliant Emergency Physician (EP) from Mt. Sinai in New York. Now pick one of your
diagnoses from above and list how you would rule-in or rule-out the diagnosis given your pretest probability. It may be a test or it may just your history and physical.
Diagnosis under consideration:
If your pre-test
probability
was...
How would you rule-in?
How would you rule-out?
Rule in:
High
Rule out:
Rule in:
Medium
Rule out:
Rule in:
Low
Rule out:
How does the concept of testing threshold work here?
Asynchronous Interactive Module (AIM)
Introduction to Emergency Medicine
Summary
That’s about it. That’s how the process work. You start with a chief complaint and make a
differential diagnosis of life and limb threats.
1. For every complaint you see during your rotation, make this list of life and limb threats. This
is the most common thing the attendings want to see you be able to do.
2. Once you have that list, use it to guide your H&P. This will allow you to keep it focused.
Remember to only ask for the factors that increase or decrease your suspicion of those
diagnoses.
3. After your evaluation, assign a pretest probability. Put some money in the game. Make a
commitment. It’s okay to be wrong. In fact, it’s good to be wrong. It’ll teach you more than
making no decision.
4. Then decide which tests will help you given your pretest probability. This is how you justify
what you’re going to order.
Any questions?