How to Use This Module?

Teacher’s Guide
Dual Process Theory
JGIM Exercises in Clinical Reasoning
Slides and Teacher’s Guide by Gabrielle Berger MD and Juan Lessing MD

Slide 1
This clinical reasoning module, based on a real case published in JGIM’s Exercises in Clinical Reasoning series, is meant to introduce the concept of dual process theory (DPT). This web series also includes modules on Problem Representation and Illness Script, which compliment this module.

How to use this module?

Any way you’d like! This module is designed with the novice as well as expert clinical reasoner in mind. As long as it is used for educational purposes and you credit JGIM, the case and module authors, you have permission to modify this module to the needs of your learner(s).

Slide 2
This module is purposely designed to be a brief introduction to the concept of dual process theory as it applies to clinical reasoning. In additional to the two objectives identified in the slide, you may also consider an aspirational goal: describe how you will use this knowledge to move between both types of reasoning more fluidly, be more conscious about the act of clinical reasoning, and impact how you think about and care for patients.

Slide 3
As described above, dual process theory is a framework adapted from the cognitive psychology literature that describes the way clinicians organize and sort through complex information to generate a differential diagnosis and narrow that differential to a focused list of MOST LIKELY diagnoses.

System 1 is intuitive and based on pattern recognition: it is what clinicians use when they recognize the presenting signs and symptoms as a pattern they’ve seen before, which quickly (and implicitly) triggers a diagnosis.

System 2 is analytic and therefore more effortful: it usually requires a systematic approach to thinking more deliberately through a problem or presentation and diagnostic possibilities. Clinicians invoke system 2 thinking when faced with particularly complex cases that don’t fit an obvious pattern or illness script (see JGIM Exercises in Clinical Reasoning on Illness Scripts for more on this topic:

With experience, some disease presentations go from requiring deliberate effort (System 2) to becoming automatic or intuitive (System 1).

Slide 4
Early career clinicians often rely on System 2 thinking: it is effortful and analytic, and allows clinicians with less experience to work through a complex case to generate a thoughtful and appropriate differential diagnosis. With more experience, clinicians develop System 1 thinking: they begin to internalize key features of different disease presentations and the ability to quickly recognize patterns that trigger a specific diagnosis or set of possible diagnoses.

However, even the experienced clinician who relies primarily on System 1 thinking must be able to move fluidly into System 2 when they do not immediately recognize a pattern (or to ensure they have not failed to consider other diagnostic possibilities). This may take many forms, including:

-Stopping or slowing down to consider other diagnostic possibilities

-Using some structure or format to consider different categories of disease; this is referred to as a diagnostic schema.

-Looking at a resource that helps consider an approach to a problem or other diagnostic possibilities

-Asking colleagues what comes to their mind

Slide 5 (No Associated Questions)

Slide 6
What do you remember about chorea?

-For some of us, all we may remember is that chorea is a movement disorder. Start by asking people to describe chorea. Chorea is a disorder of abnormal, involuntary movements that commonly affects the extremities but may also be seen in the tongue, facial muscles, and trunk. Chorea comes from the Greek word ”dance,” as the movements are reminiscent of dancing.

What diagnoses come to mind (System 1)?

-For some, Huntington disease with System 1 association. Depending on the patient population you see, some may think of Sydenham chorea associated with acute rheumatic fever from infection with Group A streptococcus pharyngitis.

What organizational approach would help you broaden your differential (System 2)?

-Many clinicians don’t have a diagnostic schema for chorea outside of the diseases mentioned above. However, some may suggest an alternative approach, such as structuring the differential by inherited versus acquired diseases, or by categories of disease including drugs and toxins, vascular injury, malignant or paraneoplastic phenomena, metabolic derangements, and other inherited disorders.

Slide 7
Use this slide and the next to illustrate the application of dual process theory to clinical reasoning –in this case, the evaluation of a patient with chorea.

Slides 8-9 (No Associated Questions)

Slide 10
This table provides additional (including less widely known) causes of chorea in an organized, structured fashion. In case you have never heard of them, neuroacanthocytosis and hepatocerebral degeneration are extremely rare diseases (ie, lower incidence and prevalence than others diagnoses on this slide) that can present with chorea.

Consider pointing out thatis this set of diagnoses all affect the Basal Ganglia. DDxdifferential diagnoses comes down to diseases of the Basal Ganglia.

Slide 11
Consider asking what stands out for your learners. They may identify the negative family history –this is important for Huntington Disease and Wilson Disease. Perhaps they will note that the patient has Vitamin B12 deficiency but is supposed to be on treatment – maybe she’s not taking it?

Slide 12 (No Associated Questions)
Slide 13
Ask your learners to share guide the group through their thoughts on the physical exam. Does the physical exam make any diagnoses more or less likely? Perhaps the lack of murmur moves rheumatic heart disease further lower down the list of possible diagnoses, and the lack of stigmata of cirrhosis makes Wilson disease less likely.

Slide 14
Note that you are now asking your learners to invoke System 2 thinking. When confronted with a complex array of symptoms and findings, clinicians should move into System 2 thinking to generate a broader differential to help guide additional workup.

Slide 15
Consider asking audience to discuss what would be their next steps? Would you perform a lumbar puncture (LP)? Would you order an MRI?

Slide 16 (No Associated Questions)
Slide 17
The problem representation is a one sentence summary that highlights the defining features of case that covers three questions: Who is the patient (pertinent demographics and risk factors), what is the temporal pattern of illness (duration and tempo of illness) and what is the clinical syndrome (key signs and symptoms)? (for more please see::

One problem representation might be: A 60 yo woman with new, subacute onset of progressive choreiform movements associated with weight loss, found to have dyskinesias and chrorea on exam and hyperintensities in the basal ganglia on brain MRI.

Slow down, model System 2 for your learners. Does your problem representation match any known illness scripts? If not, what doesn’t fit? Another way of framing this discussion is to ask your learners what are the key features of the patient’s presentation that must be explained by a diagnosis? [See the JGIM ECR website for more information on these clinical reasoning concepts:
Slide 18
Ask, what would you do next for this patient?

Anti-CRMP5 is an antibody implicated in a number of paraneoplastic neurologic syndromes including chorea, encephalomyelitis, cerebellar degeneration, and peripheral neuropathy. Paraneoplastic antibodies represent a complex immune response to antigens expressed by tumor cells. In this case, the host’s immune regulatory cells recognize proteins expressed by the tumor cells as foreign and mount an antibody response that cross-reacts with antigens found in the central and peripheral nervous system. Presence of the anti-CRMP5 antibody is strongly associated with an underlying malignancy, most commonly small cell lung cancer or thymoma.
Slides 19-24 (No Associated Questions)