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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
slide16
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

slide20
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
slide29
Pharyngitis Guideline (CDC & AAFP)
    • Reassure 0 + 1
    • Test 2
    • Test or treat 3 + 4
slide31
Pharyngitis guideline
    • Reassure 0 + 1
    • Test 2, 3 & 4
    • I become enraged with this quote
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
slide39
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 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 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
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