TDG Report

Illness scripts for improving clinical reasoning

Anna Lee, Tony Gin, Charles Gomersall, Warwick Ngan Kee, Gavin Joynt, Anthony Ho,

Juliana Chan, Lex Vlantis, James Griffith, William Wong, Coleman Fung

Clinical reasoning

Involves solving medical problems in order to make decisions about a patient’s diagnosis and management

Groves 2002

Key elements of the clinical diagnostic process

Patient’s story

Data acquisition

Accurate “problem representation”

Generation of hypothesis

Search for and selection of illness script

Diagnosis

Knowledge

Context

Experience

Bowen JL. NEJM 2006;355:2219

Development of Medical Expertise and clinical reasoning

Driving a car = “This is the steering wheel and it………This is the brake pedal……..This is a roundabout, and at roundabouts you have to…….”

Stage 1. Development of elaborate causal networks Learned during basic science years Recall facts or explain causal models

of disease processes

Schmidt et al. Acad Med 1990;65:611-21

Stage 2. Compilation of abridged networks

Starts when exposed to real patients Knowledge gets compiled (rewritten,

automated)

Schmidt et al. Acad Med 1990;65:611-21

“Diagnosing a first clinical case requires quite a lot of mental effort and involves extensive reasoning based on the elaborate causal networks available to the student, but when he sees his second or third similar case, shortcuts will emerge. He will no longer have to activate all possibly relevant knowledge in order to understand what is going on in his patient; only knowledge pertinent to understanding the case will be activated“

Remember the first time you got in a car and drove?

Stage 3. Emergence of Illness scripts

Based on repeated experience with patients

Illness scripts are sufficient to diagnose and treat diseases

Schmidt et al. Acad Med 1990;65:611-21

OK, you passed the driving test. Are you likely to be over confident? Can you assess risks quickly and accurately?

Illness scripts

Enabling Conditions

Eg. Being male, older, smoking

Consequences

Eg. Profuse sweating, SOB, severe and radiating chest pain

Fault

Eg. Myocardial infarction

Van Schaik et al. J Exp Psychol 2005;11:187-99

Stage 4. Storing patient encounters as instance scripts

Based on long experience Physician remembers many individual

patients but each has a different variant of the disease

New (or newly sick) patients are recognized as “similar to Patient X” treated as Patient X was treated

Schmidt et al. Acad Med 1990;65:611-21

Now you’ve been driving for years. Are you sure you are up to date with the highway code? And technically, are you sure you have picked up all good habits (shortcuts), and no bad habits?

Project objectives

To develop and implement a teaching module to improve 4th year medical students’ clinical reasoning skills

To assess students’ level of clinical reasoning skills

Teaching intervention

Rotation to 4th year Family Medicine module Short lecture on clinical reasoning and

illness script theory (0.5h) Small group work on “problem

representation” (1.5h) Individual guided computer work using

clinical reasoning scenarios (1.5h)

Example of clinical reasoning problem

•Pull down menus

Key elements of the clinical diagnostic process

Patient’s story

Data acquisition

Accurate “problem representation”

Generation of hypothesis

Search for and selection of illness script

Diagnosis

Knowledge

Context

Experience

Bowen JL. NEJM 2006;355:2219

Assessment of clinical reasoning (1)

Diagnostic Thinking Inventory Flexibility in thinking Structure of knowledge in memory

CUHK teachers (n=7) Flexibility in thinking (77%) Structure of knowledge in memory

(78%)

Bordage et al. Med Educ 1990;24:413-25

Assessment of clinical reasoning (2)

Clinical reasoning problems Different set of scenarios Students type their answers/cut and

past key features from scenarios (spell-check features)

Scores given to correct diagnoses and key features

Assessing students’ learning outcome

Students Begin rotation Teaching package End of rotation

Intervention DiagnosticThinkingInventory (25 min online)

Clinical reasoning Diagnostic ThinkingInventory + clinicalreasoning scenarios on web(2 hours)

Control DiagnosticThinkingInventory (25 min online)

Self-directed learning

Diagnostic ThinkingInventory + clinicalreasoning scenarios on web(2 hours)