Clinical reasoning: lessons learned from pharyngitis!

1. Clinical reasoning: lessons learned from pharyngitis! • Robert M. Centor, MD, FACP • Dean, HRMC, UAB

2. 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

3. 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

4. Why clinical reasoning • Kassirer: • Academic Medicine July, 2010 “Teaching Clinical Reasoning” • WAR research • Value of attendings sharing their thought processes

5. The tyranny of a term • 29-year-old woman c/o of fever and cough • Abnormal CXR • Treated for CAP with azithromycin

7. 1 week later • CXR has worsened • Admitted for CAP • Treated with moxifloxacin • D/C’ed after 4 days

8. 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

9. 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”

10. The tyranny of a term • CAP • CHF • “Just a sore throat”

11. Dual-process reasoning

12. Intuitive or automatic • Problem representation (should include context) • Illness scripts • Often involves pattern recognition • Contextual cues

13. 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

14. 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

15. My pharyngitis evolution • How my problem representation and illness scripts evolved over 30 years • The following cases tell a cautionary tale

16. 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)

17. 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.

18. The MODEL • Four factors, equally weighted • Tonsillar exudates • Swollen, tender anterior cervical nodes • Lack of cough • Fever

19. History of fever • Tonsillar exudates • Swollen, tender, anterior cervical nodes • Lack of cough Probability Estimates

20. 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

21. 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

22. 2000

23. Adios pharyngitis – 1993 Eponym first used 2000 The prevailing paradigm An eponym

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

25. The current paradigm

26. The current paradigm

27. The current paradigm

28. 2001

29. Pharyngitis Guideline (CDC & AAFP) • Reassure 0 + 1 • Test 2 • Test or treat 3 + 4

30. 2002

31. Pharyngitis guideline • Reassure 0 + 1 • Test 2, 3 & 4 • I become enraged with this quote

32. 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.”

33. 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

34. Stimulus for blog & new interest

35. 2005

36. 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?

37. 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

38. 2006

39. 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

40. 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

41. Laboratory Data • Negative rapid test • Negative mono spot test • CT of neck

42. Enlarged Palatine tonsils

43. 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

44. 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.

45. Differential continued • Peritonsillar abscess • Lemierre’s syndrome • F necrophorumbacteremic pharyngitis

46. 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

47. 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

48. Increasing interest in Lemierre • Repeated blog entries • Many comments including the mother of a Lemierre syndrome survivor • Multiple emails • Multiple newspaper links

49. 2008

50. Justin Rodgers • Day 1 – sore throat • Day 2 – doc started Z-pack • Day 3-6 – fevers to 102 pain & swelling Right neck