When reasoning goes wrong…
Reasoning and decision errors:
cognitive mechanisms and prevention: Utopia?
Prof. Mathieu Nendaz, University of Geneva
Prof. Geoff Norman, McMaster University
Dr. Christian Schirlo, Universität Zürich
ISFM SYMPOSIUM, Bern – September, 2016
1
A real story…
46 y.-o. man
from Moldavia,
house builder
• Occipital
headache for 2
days
Fever 38.2
Stiffness of neck
LP
• WBC 50,
lymphocytic,
glucose N, prot.
0.65 g/l
Hypothesis:
méningitis
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Admitted on a
Friday
• Viral meningitis as
a working
diagnosis
• Observation and
analgesia
3
A real story… (con’t)
Sunday
• Neck pain
increases, intensity
++++
History
completion
• For 3 weeks:
• Progressive neck
pain, slight fever,
some chills,
paresthesia of 2
hands
• Skin wound 2
months earlier,
self-treated
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Physical exam
Hypothesis
• Neck stiffness, local
palpation painful
+++
• Erythematous
wound forearm left
• Neck infectious
process
4
Investigations: radiology and bacteriology
final Dx:
 Cervical
spondylodiscitis with
paracervical abcess due
to S aureus infection
 With meningeal
inflammation and
reaction
Hoang J K et al. AJR 2011;196:W426-W432
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5
What happened ?
Was there a diagnostic error ?
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6
Error or fault ?
• Error
• Fault
• “the failure to
(a) establish an accurate and
timely explanation of the
patient’s health problem(s)
or (b) – to communicate that
explanation to the patient (IOM
2015)”
• Does not necessarily imply
consequences for the patient
• Notion of non-respect for a
procedure
• Notion of lack of diligence,
negligence
• Forensic aspects
YES there was an initial diagnostic error
Not the right diagnosis was raised, thus right tests not
performed, thus right treatment not introduced.
Even if no serious consequence for the patient, delay in
diagnosis and treatment
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Exercise : discussion
•Raise and justify possible causes/mechanisms
of this diagnostic error
•What could we do about diagnostic error?
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8
46 y.-o. man
from Moldavia,
house builder
• Occipital
headache for 2
days
Fever 38.2
Stiffness of neck
Sunday
• Neck pain
increases, intensity
++++
LP
• WBC 50,
lymphocytic,
glucose N, prot.
0.65 g/l
Hypothesis:
méningitis
History
completion
• For 3 weeks:
• Progressive neck
pain, slight fever,
some chills,
paresthesia of 2
hands
• Skin wound 2
months earlier,
self-treated
M Nendaz 2016
Admitted on a
Friday
• Viral meningitis as
a working
diagnosis
• Observation and
analgesia
Physical exam
Hypothesis
• Neck stiffness, local
palpation painful
+++
• Erythematous
wound forearm left
• Neck infectious
process
• MRI: cervical
abscess
9
Makary MA, Daniel M. Medical error—the third leading cause of death in the US.
BMJ. 3 mai 2016;i2139.
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10
Diagnostic errors in medical practice
Berner E. Am J Med 2008;121:S2–S23
• Analyses based on:
• Autopsies
• 2nd opinions, case reviews
• Actor patients consulting in clinics and private offices
5
• Visual disciplines (radiology, pathology, dermatology)
• 5-10 % of activity
95
• Clinical disciplines (e.g. internal medicine)
• About 15% of activity
• 93% due to errors regarding:
•
•
•
•
•
•
15
Cancer
Post-trauma lesions
Surgical problems
Infections
Myocardial infarction
Thromboembolic disease
85
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11
Origin of diagnostic errors
Graber M. Arch Intern Med. 2005;165:1493-1499
Singh. JAMAinternmed 2013;173(6): 418–425
7%: no-fault error
46%
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Mechanisms of cognitive errors
13
http://www.montrealconferenceclinicalreasoning.ca/fr
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• A small problem…
– A pen plus an eraser cost a total of 1.10 $
– The pen costs 1$ more than the eraser
– What is the price of the eraser ?
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Kahneman D. Thinking fast and slow.
Ed Farrar, NY, 2011
14
2 systems of thinking
System 1
System 2
Stanovich KE. BEHAVIORAL AND BRAIN SCIENCES
(2000) 23, 645–726
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15
Initial information about patient in context (e.g. chest pain)
Cognitive and/or external factors:
ANALYTICAL PROCESS
NON ANALYTICAL PROCESS
Problem representation
Immediate recognition of
clinical picture
Hypothesis generation
Data interpretation
dual
process
Hypothesis verification
Additional data collection
Working hypothesi(e)s– management decisions
Nendaz et al. Ped Med 2005;6:235–54. Nendaz et al. J Gen
Intern2016
Med. 2006;21(12):1302–5.
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Pelaccia Med Educ Online. 2011;16. Norman Acad Med. 2013;88:1058–1060. Custers Acad Med. 2013;88:1074–1080
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Initial information about patient in context (e.g. chest pain)
Cognitive and/or external factors:
ANALYTICAL PROCESS
NON ANALYTICAL PROCESS
Problem representation
Immediate recognition of
clinical picture
Hypothesis generation
Data interpretation
dual
process
Hypothesis verification
Additional data collection
Possible premature diagnostic closure  risk of diagnostic error !
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17
Problem representation
activation
Organized knowledge
Scripts
Diagnostic hypotheses
representation
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Collection of
additional information
18
The recognition of the clinical picture will depend on clinical data
searched for or valorized to build problem representation
Fever, headache,
neck stiffness, LP
with lymphocytes
Viral meningitis
Fever, headache, neck stiffness,
LP with lymphocytes
Infectious cervical process with
continuity meningeal
inflammation
• Duration > 3 weeks
• Vertebral pain at palpation
• General symptoms
• Skin wound
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Initial information about patient in context (e.g. chest pain)
Cognitive and/or external factors:
ANALYTICAL PROCESS
NON ANALYTICAL PROCESS
Problem representation
Immediate recognition of
clinical picture
Hypothesis generation
Data interpretation
dual
process
Hypothesis verification
Additional data collection
Possible premature diagnostic closure  risk of diagnostic error !
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20
Init ial infor m at ion about pat ient in cont ext (e.g. chest pain)
Cognit ive and/or ext er nal fact or s:
A N A LYT ICA L PROCESS
N ON A N A LYT ICA L PROCESS
Problem represent at ion
Im m ediat e recognit ion of
clinical pict ure
H ypot hesis gener at ion
Dat a int er pret at ion
dual
process
H ypot hesis ver ificat ion
A ddit ional dat a collect ion
Possible prem at ure diagnost ic closure  r isk of diagnost ic
er ror ! M Nendaz 2016
21
Sources of cognitive errors (%)
3
33
14
knowledge
data collection
data integration
50
data verification
Bordage G. Acad Med 1999;74:S138-43
Graber M. Arch Intern Med. 2005;165:1493-1499
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The recognition of the clinical picture will depend on clinical data
searched for or valorized to build problem representation
The clinical data searched will depend on hypotheses raised
Fever, headache,
neck stiffness, LP
with lymphocytes
Viral meningitis
Fever, headache, neck stiffness,
LP with lymphocytes
Infectious cervical process with
continuity meningeal
inflammation
• Duration > 3 weeks
• Vertebral pain at palpation
• General symptoms
• Skin wound
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In practice: reasoning shortcuts
(sometimes dangerous…)
Heuristics  Biases
Tversky and Kahneman
24
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Dr A
• Recently worked up a patient admitted for severe hypertension
• Diagnosis: Cushing’s disease!
• Thinks of Cushing’s disease in every hypertensive patient
 Availiability bias
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Dr C
• Headache in a 32 y.o. patient: hypothesis of migraine
• Looks for characteristics to confirm this dx
• Does not look for other elements which could infirm this dx
• The patient also had memory loss and ataxia
 dx was a brain tumor…
•  anchoring and confirmation biases
• Difficulty to dismiss initial hypothesis (tunnel effect)
• Efforts on confirming initial hypothesis
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Some other heuristics and biases
• Representativeness (e.g. from hospital to private practice)
• Narcissic…
• Overconfidence, unability to suspect own flaw in reasoning
• Even more important in less experimented physicians !
• Visceral, emotional
•…
Consequences:
Premature diagnostic closure
No verification of initial hypotheses
Inappropriate Decision
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Elstein A. Acad Med 1999;74:791
27
Am J Med 2008;121:S2–S23
Personal factors
• Knowledge, competence,
experience
• Self-confidence
• Autoreflexivity
• Cognitive biases, emotions
Setting factors
Patient factors
• Supervision
• Working conditions
• Overload, stress…
• Case complexity
• Relationship
complexity
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Durning et al. Acad Med. 2013;88:442–448
During the next 30 min.
Prof Norman:
Comments on cognitive
mechanisms of errors?
and
Can we do something about
diagnostic errors ?
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