The Hare and the Tortoise 2)Describe mitigating strategies - - PowerPoint PPT Presentation

6/19/2019 1

The Hare and the Tortoise

Improving Our Approach to Clinical Reasoning

Bradley Monash, MD Associate Professor, Medicine & Pediatrics Associate Chief, Division of Hospital Medicine UCSF Division of Hospital Medicine

Session goals

1)Recognize pitfalls in the diagnostic reasoning process 2)Describe mitigating strategies 3)Understand why I’ve chosen this silly analogy

Session Agenda

1) Diagnostic error 2) Four illustrative cases 3) The diagnostic process 4) Mitigating strategies

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Dx Errors Are Common

• Autopsy series 1966-2002
• “Major errors” (missed diagnosis that would have

changed management): 23.5%

• “Class I errors”: (missed diagnosis that may have

contributed to death): 9.0% ~40k-80k inpatients/yr may die with a missed diagnosis

Origins of diagnostic error in 100 patients

Arch Int Med 2005; 165(13): 1493-9.

19% Systems Error 28% Cognitive Error 46% Systems and Cognitive Errors 7% due to “no fault” error (e.g, unusual presentation; rare disease)

Watson, MD?

4 cases

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Case 1: Burma Superstar

• 65-year-old man returned from Myanmar 7d

ago, presenting with 2d fevers and a rash.

• USOH until 2d ago, developed fevers to 102,

chills, macular rash on extremities.

• ROS notable for 5 lb weight loss, malaise

T 100.8 P 91 BP 104/74 RR 20 SpO2 98% RA

• Ill, non-toxic appearing
• Pale conjunctivae, MM tacky
• Regular, soft systolic murmur at apex
• Lungs clear
• Abd soft, nd/nt
• Ext wwp
• Macular, pinpoint erythematous rash on legs

Case 1: Continued

T 100.8 P 91 BP 104/74 RR 20 SpO2 98% RA

• Ill, non-toxic appearing
• Pale conjunctivae, MM tacky
• Regular, soft systolic murmur at apex
• Lungs clear
• Abd soft, nd/nt
• Ext wwp
• Macular, erythematous rash on legs

Case 1: Continued

• LFTs wnl
• Coags wnl
• UA neg
• CXR clear

72% PMNs 19 % lymphs 9% monos

Case 1: Continued

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What’s your next move?

• A. Provide supportive care without diagnostic

evaluation

• B. Send dengue serologies and discharge with

follow-up

• C. PET scan
• D. Bone marrow biopsy
• E. Travel to Myanmar to uncover the elusive

source of his fevers

Provide supportive care wit... Send dengue serologies and ... PET scan Bone marrow biopsy Travel to Myanmar to uncov..

0% 83% 0% 17% 0%

https://www.cdc.gov/mmwr/preview/mmwrhtml/ss6203a1.htm

• Dengue serologies sent
• Supportive care
• IVF, friendly banter
• Discharged with plan for outpatient follow-up

Case 1: Continued

2 weeks later…

• More fevers
• More rash
• More malaise
• Dengue negative
• Readmitted

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65-year-old man with fevers, weight loss, petechiae and pancytopenia

What’s your next move?

• A. Provide supportive care without diagnostic evaluation
• B. Send dengue serologies and discharge with follow-up
• C. PET scan
• D. Bone marrow biopsy
• E. Travel to Myanmar to uncover the elusive source of his

fevers

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What’s your next move?

• A. Provide supportive care without diagnostic evaluation
• B. Send dengue serologies and discharge with follow-up
• C. PET scan
• D. Bone marrow biopsy
• E. Travel to Myanmar to uncover the elusive source of his

fevers

65-year-old man returned from Myanmar, p/w 2d fevers and a rash. 65-year-old man returned from Myanmar, p/w 2d fevers and a rash.

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65-year-old man returned from Mexico, p/w 2d fevers and a rash.

Framing

The error of initiating diagnostic reasoning by

• vervaluing an item of clinical information that

is presented early in the process.

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Would you intervene?

Lancet 1992;339:1520–1522

Radiation vs. Surgery?

Framework Survival vs. Mortality 90/100 survive vs. 10/100 die

N Engl J Med 1982;306:1259-1262.

Radiation vs. Surgery “Survive”: 16-17% “Die”: 40-50%

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Case 2: Fog Harbor

• 63-year-old woman with h/o pancreatic divisum,

hysterectomy, presenting with 3 weeks of intermittent abdominal pain, nausea/vomiting.

• The pain is sharp, constant, periumbilical and RLQ, worse with

eating, associated with bilious emesis.

• Typical “flares” last for a week prior to resolving
• Recent hospitalization without dx

Case 2: Continued

• Pain recurred suddenly at ~1am.
• +Nausea, emesis. No stool x 2 days.
• Abdomen soft, diffusely tender, +rebound and

“voluntary” guarding

• CT from recent admission reportedly negative
• Admit to surgery for r/o “surgical abdomen”

Case 2: Continued

• Exam stabilized, no surgical process clearly identified.
• “Transfer to Medicine”
• Pt developed worsening pain
• Pelvic ultrasound obtained

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“Pelvic fluid collection, rule out TOA”

• No malignancy
• Progression of tubo-ovarian abscesses.
• Thickening and hyperemia of the appendix, likely

secondary to the tubo-ovarian abscesses.

Case 2: Continued

• Surgery re-consulted – deferred to Gyn for TOA management
• Gynecology recommended non-operative management
• Broad-spectrum IV antibiotics started for TOA
• Patient feeling well: “So what’s the plan, doc?”

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What’s your next move?

• A. Tell surgery to take out the appendix!
• B. Call IR to drain the fluid
• C. Setup a PICC for home antibiotics
• D. Order a PET to find an occult malignancy
• E. TOA’s make you weary, so to make up your

mind you’re asking SIRI

T e l l s u r g e r y t

• t

a k e

• u

t t h e . . . C a l l I R t

• d

r a i n t h e f l u i d S e t u p a P I C C f

• r

h

• m

e a n t i b i . . . O r d e r a P E T t

• f

i n d a n

• c

c u l . . . T O A ’ s m a k e y

• u

w e a r y , s

• t

. . .

25% 33% 0% 33% 8%

Case 2: Continued

• Fluid sampled by IR – no growth (on abx)
• Discharged on abx with outpatient follow-up for malignancy
• 2 more admissions for the same symptomatology
• Query: pseudomyxoma peritonei
• Scheduled for elective ex-lap and appendectomy

Case 2: Continued

Operative Note Laparoscopic appendectomy converted to open partial cystectomy due to erosion of appendiceal pathology into her bladder. Pathology Appendix with fibrous obliteration and dissecting acellular

• rganizing mucin, consistent with past rupture

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What’s your next move?

• A. Tell surgery to take out the appendix!
• B. Call IR to drain the fluid
• C. Setup a PICC for home antibiotics
• D. Order a PET to find an occult malignancy
• E. TOA’s make you weary, so to make up your mind you’re

asking SIRI

What’s your next move?

• A. Tell surgery to take out the appendix!
• B. Call IR to drain the fluid
• C. Setup a PICC for home antibiotics
• D. Order a PET to find an occult malignancy
• E. TOA’s make you weary, so to make up your mind you’re

asking SIRI

Tubo-ovarian abscess?

Blind Obedience

Showing undue deference to technology or authority.

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“Nobody’s perfect.” Anchoring

The formulation of an initial probability of a diagnosis based on information at hand, and not adjusting this probability as new clinical data are obtained.

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“Estimate percentage of countries in Africa that are members of the United Nations (UN).”

Science 1974. 185;4157:1124-31

25%

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45%

8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8

= 512 = 2250

Science 1974. 185;4157:1124-31

“Admit for ____” “Admitted for ____”

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“Assess for ____” “Consult for ____”

https://pxhere.com

Case 3: Deja Vu

• A 67-year-old woman with h/o DM and HTN, presented

with 4 months of abdominal pain and recurrent nausea

• Periumbilical pain, worse with eating. +Diarrhea, decreased

appetite, weight loss

• Multiple negative outpatient investigations
• CBC, chemistries, LFTs, stool cx + O&P, anti-TTG
• CT: L adrenal cyst, atheroma within the abdominal aorta,

uncomplicated cholelithiasis

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• Admitted with ongoing pain and PO intolerance
• +Nausea, diarrhea
• Abdomen soft, diffusely tender, +rebound and

“voluntary” guarding

• Repeat labs unrevealing
• Prior CTs reviewed without obvious source…

Case 3: Continued

thepix.info Ther Adv Gastroenterol 2015.8;(3):160–2

What’s your next move?

• A. Tell surgery to take out the appendix!
• B. Order a PET to find an occult malignancy
• C. Order CT angiography of the mesenteric vessels
• D. Order MR enterography and fecal calprotectin
• E. I don’t care – I’m done with these mind games

T e l l s u r g e r y t

• t

a k e

• u

t t h e . . . O r d e r a P E T t

• f

i n d a n

• c

c u l . . . O r d e r C T a n g i

• g

r a p h y

• f

t h . . . O r d e r M R e n t e r

• g

r a p h y a n d . . . I d

• n

’ t c a r e – I ’ m d

• n

e w i t h . . .

0% 5% 0% 18% 77%

• Continued abx, multiple consultants following
• Several days later, severe abdominal pain, increased

tenderness with worsening peritoneal signs, WBC 16k

• CT angiography: severe ostial stenoses of the celiac and

superior mesenteric arteries

Case 3: Continued

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Case Rep Gastroenterol 2016;10:68–74

• Continued abx, multiple consultants following
• Several days later, severe abdominal pain, WBC 16k
• CT angiography demonstrated short 90% ostial stenoses of

the celiac and superior mesenteric arteries and an occluded left common iliac artery.

• Dx: Chronic mesenteric ischemia
• Rx: Angioplasty and stenting with symptom resolution

Case 3: Continued What’s your next move?

• A. Tell surgery to take out the appendix!
• B. Order a PET to find an occult malignancy
• C. Order CT angiography of the mesenteric vessels
• D. Order MR enterography and fecal calprotectin
• E. I don’t care – I’m done with these mind games

What’s your next move?

• A. Tell surgery to take out the appendix!
• B. Order a PET to find an occult malignancy
• C. Order CT angiography of the mesenteric vessels
• D. Order MR enterography and fecal calprotectin
• E. I don’t care – I’m done with these mind games

6/19/2019 19

Chronic appendicitis

Availability

The tendency to make a diagnosis based on the ease of recalling past cases, especially those that were recent or had a high impact.

• 122 Surgeons and Anesthesiologists asked to estimate risk
• f ACS due to withholding transfusion in a clinical vignette

(+) prior bad outcome – 10% (-) prior bad outcome – 5%

• Mean actual risk = 4%

To Transfuse or Not To Transfuse?

JAMA 1990;264:476–483

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• 122 Surgeons and Anesthesiologists asked to estimate risk
• f ACS due to withholding transfusion in a clinical vignette

(+) prior bad outcome – 10% (-) prior bad outcome – 5%

• Mean actual risk = 4%

To Transfuse or Not To Transfuse?

JAMA 1990;264:476–483 www.reddit.com

Case 4: Original Pattern

• A 27-year-old man presented to the ED with sudden onset

headache, palpitations and diaphoresis.

• Most recent episode started while watching TV
• T 37.6 BP 158/86 HR 112 RR 24 SpO2 98% RA
• He was diaphoretic with bounding precordial impulse
• 24-hour urinary fractionated catecholamines and

metanephrines were sent…

Case 4: Continued

• … and were negative
• Further history revealed he had prior episodes, which

started after he watched the 911 terrorist attacks

• He was diagnosed with panic disorder and treated

accordingly.

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Representativeness

Ignoring prior probabilities and base rate frequencies of different diagnoses that seem to match the patient’s presentation.

93% of students consider themselves above average drivers 94% of professors consider themselves above average teachers A lawyer or an engineer?

• T

wo groups given same sets of 5 personality descriptions chosen randomly from 100

• “Estimate probability the person is an engineer”
• Group 1: 70 lawyers, 30 engineers
• Group II: 30 lawyers, 70 engineers
• Both groups had the same estimate
• Judgments made on personality stereotypes

Psychol Rev 1973;80:237-251

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iom.nationalacademies.org

Clinical Reasoning = (Diagnostic) Decision-Making

• Relies on attention and cognition
• Influenced by:
• Intelligence and knowledge
• Recent and remote experiences
• Age & Experience
• Mood
• Fatigue
• Stress
• Hunger

Clinical Reasoning = (Diagnostic) Decision-Making

• Relies on attention and cognition
• Influenced by:
• Intelligence and knowledge
• Recent and remote experiences
• Age & Experience
• Mood
• Fatigue
• Stress
• Hunger

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Researchgate.net

Stress / Arousal Performance

Researchgate.net

Stress / Arousal Performance Learning

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Study.com

Dual Process Theory

System I (Intuitive) Cognitive Style Heuristic Cognitive Awareness Low Automaticity High Rate Fast Effort Low Emotional Component High Scientific Rigor Low

Dual Process Theory

Adv in Health Sci Ed 2009; 14:27-35

System I (Intuitive) Cognitive Style Heuristic Cognitive Awareness Low Automaticity High Rate Fast Effort Low Emotional Component High Scientific Rigor Low

Dual Process Theory

Adv in Health Sci Ed 2009; 14:27-35

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Heuristics

Experience-based cognitive shortcuts that enable rapid synthesis of a barrage of data

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System I (Intuitive) System II (Analytical) Cognitive Style Heuristic Systematic Cognitive Awareness Low High Automaticity High Low Rate Fast Slow Effort Low High Emotional Component High Low Scientific Rigor Low High

Dual Process Theory

Adv in Health Sci Ed 2009; 14:27-35

Problem Solving Opening a Door

N Engl J Med 2006;355:2217-25

Patient’s Story Data Acquisition Problem Representation Hypothesis Generation Search/Select Illness Script Diagnosis

Knowledge Context Experience

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“The way to block errors that originate in System 1 is simple in principle: recognize the signs that you are in a cognitive minefield, slow down, and ask for reinforcement from System 2.” “The way to block errors that originate in System 1 is simple in principle: recognize the signs that you are in a cognitive minefield, slow down, and ask for reinforcement from System 2.”

How to Avoid Cognitive Errors (TRAPS) How to Avoid Cognitive Errors (TRAPS)

T – Time out R – Reframe A – Adjust ddx P – Problem list S – Seek Support

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Time Out

Diagnostic Time Out

• “Was I comprehensive?”
• “Did I consider the inherent flaws of

heuristic thinking?”

• “Was my judgment affected by any
• ther bias?”
• “Do I need to make the diagnosis now,
• r can I wait?”
• “What is the worst-case scenario?”

Academic Medicine. 2011;86(3):307-13

Reframe

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Adjust Adjust

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Problem List Seek Support

National Academies of Medicine Report, 2015

Seek Support

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Acknowledgements

• Thank YOU!!!
• Vickrey BG, Samuels, MA, Ropper AH. How Neurologists Think: Cognitive

Psychoology Perspective on Missed Diagnoses. Ann Neurol 2010;67:425–433

• Tversky A and Kahneman D. Judgment under Uncertainty: Heuristics and Biases.

Science 1974. 185;(4157):1124-31

• Moulton CE, Regehr G, Mylopoulos M, MacRae HM. Slowing Down When You

Should: A New Model of Expert Judgment. Acad Med 2007;82(10):S109-16

• Rajkomar A, Dhaliwal G. Improving Diagnositc Reasoning to Improve Patient
• Safety. The Permanente Journal 2011;15(3):68-73
• www.cbsnews.com/news/everyone-thinks-they-are-above-average/
• Google images

Questions?