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Clinical reasoning: lessons learned from pharyngitis!. Robert M. Centor, MD, FACP Dean, HRMC, UAB. Roadmap. Clinical reasoning System 1 – Intuitive (FAST) System 2 – Analytic (SLOW) My evolving problem representation and illness scripts Adult sore throats – morbidity & mortality And why?

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Clinical reasoning lessons learned from pharyngitis
Clinical reasoning: lessons learned from pharyngitis!

  • Robert M. Centor, MD, FACP

  • Dean, HRMC, UAB


Roadmap
Roadmap

  • Clinical reasoning

    • System 1 – Intuitive (FAST)

    • System 2 – Analytic (SLOW)

  • My evolving problem representation and illness scripts

  • Adult sore throats – morbidity & mortality

  • And why?

  • Take home lessons


Goals
Goals

  • Understand dual-process theory of clinical reasoning

  • Understand why we should expand the pharyngitis paradigm

  • Understand red flags in pharyngitis (changing the illness script)

  • Understand when to invoke analytic reasoning


Why clinical reasoning
Why clinical reasoning

  • Kassirer:

    • Academic Medicine July, 2010 “Teaching Clinical Reasoning”

  • WAR research

    • Value of attendings sharing their thought processes


The tyranny of a term
The tyranny of a term

  • 29-year-old woman c/o of fever and cough

  • Abnormal CXR

  • Treated for CAP with azithromycin


1 week later
1 week later

  • CXR has worsened

  • Admitted for CAP

  • Treated with moxifloxacin

  • D/C’ed after 4 days


2 weeks later
2 weeks later

  • Fever and cough have not subsided

  • ID consult takes a history:

    • 2 months of fever and cough

    • 9 pound weight loss

    • True night sweats daily

    • Lives in a home for former drug abusers


Diagnostic errors
Diagnostic errors

  • Patient has TB

  • The label encouraged “premature closure”

  • The physicians used intuitive decision making

  • Never moved to analytic decision making

  • They never “slowed down”


The tyranny of a term1
The tyranny of a term

  • CAP

  • CHF

  • “Just a sore throat”



Intuitive or automatic
Intuitive or automatic

  • Problem representation (should include context)

  • Illness scripts

  • Often involves pattern recognition

  • Contextual cues


Expertise vs experienced non experts
Expertise vs. experienced non-experts

  • Refining problem representation

  • Refining illness scripts

  • Knowing when to invoke analytic reasoning

    • Slowing down when you should: a new model of expert judgment

    • Moulton Acad Med 2007 vol. 82 (10 Suppl) pp. S109-16


Cap revisited
CAP revisited

  • Physicians used intuitive reasoning

  • Their illness script for CAP:

    • Fever

    • Cough

    • Abnormal CXR

  • Consultant had an expanded illness script

  • “Slowed down” and switched to analytic reasoning


My pharyngitis evolution
My pharyngitis evolution

  • How my problem representation and illness scripts evolved over 30 years

  • The following cases tell a cautionary tale


1981

  • Problem representation:

    • Does the adult pharyngitis ER patient have a strep throat?

  • Context:

    • No rapid tests yet

    • Minimal chance for follow-up

  • Illness script

    • Treat strep throat patients to prevent acute rheumatic fever

    • Strep throat patients look sicker (on average)


Group a strep prediction model
Group A Strep Prediction Model

  • 286 consecutive adult ED patients

  • 2 throat swab cultures – with specific typing of groups (A,B,C and G)

  • Logistic regression model developed

Centor. MDM – 1981.


The model
The MODEL

  • Four factors, equally weighted

    • Tonsillar exudates

    • Swollen, tender anterior cervical nodes

    • Lack of cough

    • Fever


Probability estimates

  • History of fever

  • Tonsillar exudates

  • Swollen, tender, anterior cervical nodes

  • Lack of cough

Probability Estimates


2000

  • Problem representation:

    • Provide the four clinical factors

  • Context:

    • Want to treat strep throat – several reasons

    • But we may also want to treat group C strep


Illness script 2000
Illness script 2000

  • Use the score to estimate strep probability

  • We should give strep throat patients penicillin

    • To prevent acute rheumatic fever

    • To decrease peritonsillar abscess

    • To decrease symptom duration

    • To decrease contagion



An eponym

Adios pharyngitis – 1993

Eponym first used 2000

The prevailing paradigm

An eponym


The current early 21 st century paradigm illness script
The current (early 21st century) paradigm (illness script)









Clinical infectious diseases 2002
Clinical Infectious Diseases 2002

  • “We must conclude, therefore, that the algorithm based strategy proposed in the ACP-ASIM Guideline would result in the administration of antimicrobial treatment to an unacceptably large number of patients with nonstreptococcal pharyngitis.”


Why are the conclusions different
Why are the conclusions different?

  • Different focus of illness scripts

  • ACP – more outpatient generalist focused, therefore treating the patient is the clear priority

  • IDSA – more societal focused – worried about creating antibiotic resistance




A malpractice lawyer calls
a Malpractice Lawyer calls

  • Father of 2 boys w/ documented group A strep c/o sore throat

  • Negative rapid test -> no Rx

  • Patient dies 2 days later of group A strep septicemia

  • Do they have a case?


Mistakes made 1
Mistakes Made #1

  • Ignored the concept of pretest probability

  • This is a contextual error

  • He used intuitive diagnosis and treatment, but should have invoked analytical reasoning

  • But this care does follow a guideline…

  • So probably no malpractice case



Morning Report Presentation

Symptomatic treatment

both times

Severe (10/10) throat pain, high fever, and hoarseness

Returns to ER

Worsening symptoms –

Negative Rapid Test

Presents to ER Negative Rapid Test

30 yo WF

Day 1

ER Visit

Day 5

ER Visit

Day 3

ER Visit

Day 9


Case continued
Case Continued

  • Physical examination

    • T: 101° HR: 101 RR: 18 BP: 122/78

    • Prominent exudates, non-displaced uvula

    • Anterior cervical nodes

    • Diffuse anterior neck edema

    • Diffuse moderate ant neck tenderness

  • Pharyngitis score = 4


Laboratory data
Laboratory Data

  • Negative rapid test

  • Negative mono spot test

  • CT of neck



Diagnostic studies
Diagnostic Studies

  • Culture – negative GC & chlamydia

  • Rapid flu test

  • EBV and CMV titers -

  • HIV -

  • Throat culture grew group C strep

  • Full recovery with 7 days of antibiotics


Differential of worsening pharyngitis
Differential of worsening pharyngitis

  • False negative rapid test

    • Sensitivity in practice - ~75%

  • NGA strep (group C > group G)

  • GC pharyngitis

  • Infectious Mononucleosis

  • Acute HIV infection

Shah. JGIM – 2007.


Differential continued
Differential continued

  • Peritonsillar abscess

  • Lemierre’s syndrome

  • F necrophorumbacteremic pharyngitis


Mistakes made 2
Mistakes Made #2

  • First ER visit acceptable – used intuition

  • Second ER visit – context should have triggered analytic reasoning

  • Decisions based on test results

  • Rather than patient presentation


Lesson learned from case 2
Lesson learned from Case #2

  • No previous illness script for “worsening pharyngitis”

  • Worsening pharyngitis is no longer “just a sore throat” AND

  • It REQUIRES analytic reasoning


Increasing interest in lemierre
Increasing interest in Lemierre

  • Repeated blog entries

  • Many comments including the mother of a Lemierre syndrome survivor

  • Multiple emails

  • Multiple newspaper links



Justin rodgers
Justin Rodgers

  • Day 1 – sore throat

  • Day 2 – doc started Z-pack

  • Day 3-6 – fevers to 102 pain & swelling Right neck


Justin rodgers1
Justin Rodgers

  • Admitted for metastatic lung abscesses

  • Day 9 – blood grew Fusobacterium

  • He died after 3 weeks in the ICU


Lemierre s syndrome
Lemierre’s Syndrome

  • Syndrome known since the early 1900s

  • 1936 Lancet by A. Lemierre

  • Bacillus funduliformis in 1930

  • Fusobacterium necrophorum (@ least 80%)

Lemierre. Lancet – 1936.



Lemierre s presentation1

Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation


Lemierre s presentation2

Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation

Repeated rigors


Lemierre s presentation3

Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation

Repeated rigors


Lemierre s presentation4

Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation

Repeated rigors

Metastatic abscesses


Mistakes made 3
Mistakes Made #3

  • Used azithromycin rather than penicillin

  • Primary physician stayed in automatic mode despite:

    • worsening course

    • neck swelling

    • bacteremicsymptoms


Tyranny of a term
Tyranny of a term

  • “just a sore throat”

  • Never considered switching to analytic reasoning


The danish experience 90 95
The Danish Experience 90-95

  • Incidence of necrobacillosis

    • 1.5 / million / yr

  • Incidence of Lemierre’s

    • 0.8 / million / yr

  • All 24 patients with Lemierre’s were young and previously healthy

  • Pre-hospital delay = increased morbidity

Hagelskjaer. Eur J Clin Microbiol Infect Dis - 1998.


The danish experience 98 01
The Danish Experience 98-01

  • 3 yr prospective study

  • 58 patients with Lemierre’s

  • 3.6 cases / million / yr

  • 14.4 cases / million / yr (or 1 in 70,000) for the age group 15-24

Hagelskjaer. Eur J Clin Microbiol Infect Dis - 2008.



Illness script
Illness script

  • Is our illness script wrong?

  • Should we add fuso pharyngitis to our illness script?



What data did i need
What data did I need?

  • Relative prevalence of strep and fuso pharyngitis

  • Risk of ARF from strep

  • Risk of Lemierre from fuso

  • Outcomes of ARF & Lemierre


Fusobacterium necrophorum
Fusobacterium necrophorum

  • Deduction –> F. necrophorum causes pharyngitis

  • Lemierre’s follows sore throats

  • 4 studies support F. necrophorum -> endemic pharyngitis

  • But no clinical data


Fusobacterium pharyngitis
Fusobacterium pharyngitis

  • Likely cause of endemic pharyngitis

  • More common in adolescents and young adults - ~ 10% incidence

  • Possible synergistic action with

    • EBV

    • Group C

  • No current diagnostic test

  • Differential for worsening pharyngitis




Lemierre s risk for adolescents1

6% pharyngitis

60,000/

1 million

Lemierre’s Risk for adolescents


Lemierre s risk for adolescents2

6% pharyngitis

60,000/

1 million

Lemierre’s Risk for adolescents

6000

F. necro /

1 million


Lemierre s risk for adolescents3

60,000/

1 million

Lemierre’s Risk for adolescents

14.4 Lemierre’s/

1 million

6000

F. necro /

1 million

6% pharyngitis


Lemierre s risk for adolescents4

6% pharyngitis

60,000/

1 million

Lemierre’s Risk for adolescents

14.4 Lemierre’s/

1 million

6000

Fuso /

1 million

1/400 F. pharyngitis ->

Lemierre’s




Take home points
Take home points

  • F necrophorum causes endemic pharyngitis

  • Avoid macrolides for empiric treatment

  • Pharyngitis normally resolves in 3-5 days

  • Red flags

    • Neck swelling

    • High fever, rigors, night sweats

  • For bacteremic symptoms :

    • penicillin and metronidazole

    • clindamycin


Pharyngitis illness script 2011
Pharyngitis illness script 2011

  • Pharyngitis score probably indicates bacterial pharyngitis

    • Around 75% of 3s & 4s are strep A or C

  • Both strep A & C and fuso pharyngitis deserve antibiotics

  • When symptoms worsen, switch to analytic reasoning

  • We need to revise guidelines to consider more than GAS


Clinical reasoning
Clinical reasoning

  • Expand illness scripts and therefore

  • Problem representation

  • Understand the context of the illness scripts

  • Know when to “slow down” and analyze


References
References

  • Slides and references available upon request

  • [email protected]


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