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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!

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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?

  • Take home lessons


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

  • Kassirer:

    • Academic Medicine July, 2010 “Teaching Clinical Reasoning”

  • WAR research

    • Value of attendings sharing their thought processes


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

  • CXR has worsened

  • Admitted for CAP

  • Treated with moxifloxacin

  • D/C’ed after 4 days


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

  • 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 term

  • CAP

  • CHF

  • “Just a sore throat”


Dual-process reasoning


Intuitive or automatic

  • Problem representation (should include context)

  • Illness scripts

  • Often involves pattern recognition

  • Contextual cues


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

  • 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

  • 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

  • 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

  • Four factors, equally weighted

    • Tonsillar exudates

    • Swollen, tender anterior cervical nodes

    • Lack of cough

    • Fever


  • 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

  • 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


2000


Adios pharyngitis – 1993

Eponym first used 2000

The prevailing paradigm

An eponym


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


The current paradigm


The current paradigm


The current paradigm


2001


  • Pharyngitis Guideline (CDC & AAFP)

    • Reassure 0 + 1

    • Test 2

    • Test or treat 3 + 4


2002


  • Pharyngitis guideline

    • Reassure 0 + 1

    • Test 2, 3 & 4

    • I become enraged with this quote


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?

  • 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


Stimulus for blog & new interest


2005


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

  • 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


2006


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

  • 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

  • Negative rapid test

  • Negative mono spot test

  • CT of neck


Enlarged Palatine tonsils


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

  • 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

  • Peritonsillar abscess

  • Lemierre’s syndrome

  • F necrophorumbacteremic pharyngitis


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

  • 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

  • Repeated blog entries

  • Many comments including the mother of a Lemierre syndrome survivor

  • Multiple emails

  • Multiple newspaper links


2008


Justin Rodgers

  • Day 1 – sore throat

  • Day 2 – doc started Z-pack

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


Justin Rodgers

  • Admitted for metastatic lung abscesses

  • Day 9 – blood grew Fusobacterium

  • He died after 3 weeks in the ICU


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 Presentation

Sore throat


Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation


Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation

Repeated rigors


Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation

Repeated rigors


Sore throat

4-5 days

Fever & rigors

Lemierre’s Presentation

Repeated rigors

Metastatic abscesses


Mistakes Made #3

  • Used azithromycin rather than penicillin

  • Primary physician stayed in automatic mode despite:

    • worsening course

    • neck swelling

    • bacteremicsymptoms


Tyranny of a term

  • “just a sore throat”

  • Never considered switching to analytic reasoning


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

  • 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.


Time for analytic reasoning!


Illness script

  • Is our illness script wrong?

  • Should we add fuso pharyngitis to our illness script?


Is Fuso pharyngitis as dangerous as strep pharyngitis?


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

  • Deduction –> F. necrophorum causes pharyngitis

  • Lemierre’s follows sore throats

  • 4 studies support F. necrophorum -> endemic pharyngitis

  • But no clinical data


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


2009


Lemierre’s Risk for adolescents

6% pharyngitis


6% pharyngitis

60,000/

1 million

Lemierre’s Risk for adolescents


6% pharyngitis

60,000/

1 million

Lemierre’s Risk for adolescents

6000

F. necro /

1 million


60,000/

1 million

Lemierre’s Risk for adolescents

14.4 Lemierre’s/

1 million

6000

F. necro /

1 million

6% pharyngitis


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


Lemierre’s mortality estimate


Why expand the pharyngitis paradigm!


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 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

  • Expand illness scripts and therefore

  • Problem representation

  • Understand the context of the illness scripts

  • Know when to “slow down” and analyze


References

  • Slides and references available upon request

  • rcentor@uab.edu


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