1. Sore Throat
Richard Usatine, MD

2. What are causes of sore throats?
Infectious - viral, bacterial, mycoplasma, chlamydiae, candida
Allergic - allergic rhinitis
Acid Reflux - GERD
Trauma – e.g., swallowing a chicken bone
Chemical irritants or burns
Epiglottitis
Thyroiditis
Retropharyngeal abscess

3. Infectious Causes of Pharyngitis
Adults
Viral (including mononucleosis)
30-60%
Group A Streptococcus
5-9%
Group C, G, or F Streptococcus
0-18%
N. gonorrhoeae
0-25%
Mycoplasma
10-13%
Chlamydia
9-20%
pooled data from 11 studies

4. Strep throat versus viral pharyngitis
ask about: fever, pain on swallowing
physical exam:
throat - exudate, palatal petechiae, injection, swelling
neck - tender anterior cervical adenopathy
children - strawberry tongue, sand paper rash

5. Why do we want to diagnose and treat GABHS?
to prevent rheumatic fever: less than 200 cases of acute rheumatic fever per year in the US
to prevent suppurative complications (e.g., peritonsillar abscess)
to speed up recovery and shorten duration: treatment with antibiotics (only if started early in the clinical course) speeds symptomatic recovery of patients with culture-proven GABHS by about a half day
to reduce spread to others

6. Downside of using antibiotics
Promotes antibiotic resistance
Adverse reactions such as allergy and anaphylaxis
Costly compared to health education
Patients do not need antibiotics to feel satisfied with the doctor-patient encounter (Hamm)

7. Case 1
A 25 year old man comes to your office with the complaint of a bad sore throat for 2 days. He has felt chills and fever today but has not measured his temperature. He has some pain on swallowing. He has a slight runny nose and denies cough and other symptoms. He was previously healthy.
T= 38.5
PE: ears - TM's normal
nose – clear
neck - no cervical adenopathy
lungs – clear

8. Case 1
Another strep throat

9. What is the differential diagnosis in order of likelihood?
Strep
Viral

10. Sensitivity and Specificity
Strep throat+
sensitivity
A/(A+C)
Strep throat ‑
specificity
D/(D+B)
test +
(Hx, PE or lab)
A true positive
B false positive
test ‑
C false negative
D true negative

11. Positive Predictive Value (PPV)
Changes based on the prevalence in the population
True positives/all positives
Higher prevalence increases the PPV

12. How well does PE predict strep throat?
Sensitivity
Specificity
Positive Predictive Value
Anterior Cervical adenopathy
.80
.55
.27
Tonsillar Exudate
.65
.69
.31
Tonsillar Swelling
.87
.39
.23
Injected Pharynx
.97
.18
.20

13. How well does history predict strep throat?
Sensitivity
Specificity
PPV
enlarged cervical nodes
.94
.27
.19
strep exposure
.25
.88
absence of cough
.83
.48
.22
absence of rhinorrhea
.73
.20
fever > 38.3C
.17
.33

14. History and Physical
No individual item has sufficient predictive value on its own
Need to combine items to get greater predictive value
Purpose of a clinical decision rule

15. Clinical Prediction Rule for Strep Throat
Fever over 38 C
Absence of cough
Tender ant. cervical adenopathy
Tonsillar swelling or exudate
Age< 15 y
Age> 45
McIsaac modification of the
Centor Criteria (added age) 1 -1

16. Probability of Strep throat based on points (pretest probability)
-1 to 0 1 2 3
4 or 5 1%
10%
17%
35%
51%

17. How many points does our patient have?
Fever over 38 C
Absence of cough
Tender ant. cervical adenopathy
Tonsillar swelling or exudate
Age< 15 y
Age> 45
Total = 3
Pretest probability= 35% 1

18. What are the tests? Rapid strep test Throat culture
Done in minutes in the office
Throat culture
Gold standard – how can you get false negatives or positives?
ASO titer – not useful for practicing medicine

19. How to swab for rapid strep test or culture.

21. 3 categories low probability of GABHS - no test, no treat
intermediate probability - test
high probability - treat, no test

22. Rapid Strep Test Done
Result for patient in case one:
positive

23. Antibiotic treatment PenVK 500 mg tid x 10 #30
Studies indicate increased failure rates of preventing acute rheumatic fever of 2 times with treatment of 7 days and 3 times with treatment of 5 days.
Erythromycin or Azithromycin for patients allergic to penicillin

24. What symptomatic treatment could you offer the patient?
Acetaminophen
gargling with warm salt water
throat lozenges
fluids, warm or cold, can be soothing

25. Case 2
A 30 year old man comes to your office with a scratchy throat and a headache for one day. His nose is slightly stuffy and he has a non-productive cough. He denies allergies and fever. He smokes 1 ppd.
VS : T= 37.1
PE: ears - TM's normal nose – clear mucus and boggy mucosa face - no sinus tenderness
neck - tender adenopathy

26. Case 2
mild erythema with cobblestone appearance of posterior pharynx, left tonsillar exudate present
Case 2

27. How many points does our patient have?
Fever over 38 C
Absence of cough
Tender ant. cervical adenopathy
Tonsillar swelling or exudate
Age< 15 y
Age> 45
Total = 2
Pretest probability= 17% 1

28. Rapid Strep Test Done
Result is negative
Symptomatic treatment

29. Case 3
A 6 year old girl is brought to your office with low grade fever, sore throat, and poor appetite for 3 days. Father states that she does not have cough or runny nose. No vomiting or diarrhea. She is allergic to Penicillin.
PE : T = 38.2 P 110
ears - TM's normal
nose - clear
throat - tonsils - beefy red and almost touching in midline. Uvula in midline, no exudate, no petechiae
neck - enlarged tender anterior cervical nodes
lungs – clear
skin - sandpaper rash prominent around axilla

30. Case 3
Case 3

31. Scarlet fever How do we treat this?
What does this have to do with rabbits?

32. Case 4
A 19 year old woman comes to your office with 2 days of sore throat, cough, and runny nose. Patient feels feverish but has not taken her temperature. She has no other symptoms and no history of other medical problems. The patient very much wants penicillin.
T = P 80
ears - TM's normal
nose - boggy red mucosa with clear mucus
neck - shotty nodes
lungs - clear

33. Case 4
Viral 19yo with rhinitis and cough too.

34. How many points does our patient have?
Fever over 38 C
Absence of cough
Tender ant. cervical adenopathy
Tonsillar swelling or exudate
Age< 15 y
Age> 45
Total = 0
Pretest probability= 1%

35. What do you do?
No test
No treat – no antibiotics
Treat symptoms

36. Case 5
A 25 year old woman comes to your office with a severe sore throat for 4 days and has difficulty swallowing. She now feels very hot and has been off work for 2 days. Her neck also hurts. She denies cough and rhinitis. No known allergies. Patient appears to be in moderate distress but she is able to breath comfortably.
T = 39.5
ears - normal
nose - clear
throat - it is difficult for the patient to open her mouth because of pain
neck - bilateral anterior cervical adenopathy with right worse than left

37. Case 5
Case 5

39. Peritonsillar Abscess

40. Peritonsillar Abscess
Another peritonsillar abscess, not a case

41. Case 6
A 16 year old girl is brought to your office by her mom for a fever and sore throat. She complains that it hurts to swallow and she has swollen glands. A friend was diagnosed with "mono" 3 weeks ago. Patient has no known history of mono. Patient denies cough and runny nose. Her temperature last night was 103 degrees F (oral).
T = /65 P 100
neck - bilateral enlarged tender anterior cervical nodes and smaller posterior cervical adenopathy
lymph nodes – axillary adenopathy
lungs - clear
abd - no splenomegaly

42. Case 6

43. Differential Diagnosis
Mononucleosis
Strep Throat
Viral
Consider a CBC and a monospot.
EBV VCA-IgM is more sensitive but more expensive.

44. Case 7
A 41 year old man comes to your office with a painful throat and a headache for one day. No cough.
T = 38.1 BP 150/90 P 70
ears - TM's normal
nose - clear
neck - right anterior cervical node is tender and enlarged
lungs - clear

45. Case 7
deep erythema, palatal petechiae and no exudate, tonsillar swelling present

46. How many points does our patient have?
Fever over 38 C
Absence of cough
Tender ant. cervical adenopathy
Tonsillar swelling or exudate
Age< 15 y
Age> 45
Total = 4
Pretest probability= 51% 1

47. www.med.sc.edu:85/ fox/strep-thr.jpg

48. Case 1

49. Strep Throat
Strep throat

50. Candida in a man with AIDS
Candida pharyngitis in a man with AIDS

51. Viral
Another viral pharyngitis – girl age 14

52. Herpangina
Herpangina, little ulcers on the soft palate

53. Coxsackie A16 Virus
herpangina.jpg

55. Summary
Use of clinical prediction rule to diagnose sore throat (useful in other diseases)
Clinical prediction rule helps to establish pretest probability and put patient in one of three categories
No test, no treat
Test and treat based on result
No test, just treat
Use antibiotics for sore throat when probability of strep throat is above your treatment threshold

56. Photographs by: Richard Usatine, MD for slides 4, 12 and 14
Hospital Practice
Web sites
icarus.med.utoronto.ca/carr/manual/pta.html
Atlas of Infectious Diseases

57. Useful web sites: MedRules has the pharyngitis prediction rule:
Or get it at Ectopic Brain, a great site for other PDA software: