Sore Throat

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Sore Throat

• Richard Usatine, MD

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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

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Infectious Causes of Pharyngitis
Cause 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 pooled data from 11 studies
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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

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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

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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)

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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
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Case 1
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What is the differential diagnosis in order of
likelihood?

• Strep
• Viral

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Sensitivity and Specificity
Strep throat sensitivity A/(AC) Strep throat - specificity D/(DB)
test (Hx, PE or lab) A true positive B false positive
test - C false negative D true negative
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Positive Predictive Value (PPV)

• Changes based on the prevalence in the population
• True positives/all positives
• Higher prevalence increases the PPV

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

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Clinical Prediction Rule for Strep Throat
Fever over 38 C Absence of cough Tender ant. cervical adenopathy Tonsillar swelling or exudate Agelt 15 y Agegt 45 McIsaac modification of the Centor Criteria (added age) 1 1 1 1 1 -1
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Probability of Strep throat based on points
(pretest probability)
-1 to 0 1 2 3 4 or 5 1 10 17 35 51
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How many points does our patient have?
Fever over 38 C Absence of cough Tender ant. cervical adenopathy Tonsillar swelling or exudate Agelt 15 y Agegt 45 Total 3 Pretest probability 35 1 1 0 1 0 0
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What are the tests?

• Rapid strep test
• 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

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How to swab for rapid strep test or culture.
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3 categories

• low probability of GABHS - no test, no treat
• intermediate probability - test
• high probability - treat, no test

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Rapid Strep Test Done

• Result for patient in case one
• positive

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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

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What symptomatic treatment could you offer the
patient?

• Acetaminophen
• gargling with warm salt water
• throat lozenges
• fluids, warm or cold, can be soothing

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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

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Case 2
mild erythema with cobblestone appearance of
posterior pharynx, left tonsillar exudate present
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How many points does our patient have?
Fever over 38 C Absence of cough Tender ant. cervical adenopathy Tonsillar swelling or exudate Agelt 15 y Agegt 45 Total 2 Pretest probability 17 0 0 1 1 0 0
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Rapid Strep Test Done

• Result is negative
• Symptomatic treatment

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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

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Case 3
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Scarlet fever

• How do we treat this?
• What does this have to do with rabbits?

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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 37.4 P 80
• ears - TM's normal
• nose - boggy red mucosa with clear mucus
• neck - shotty nodes
• lungs - clear

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Case 4
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How many points does our patient have?
Fever over 38 C Absence of cough Tender ant. cervical adenopathy Tonsillar swelling or exudate Agelt 15 y Agegt 45 Total 0 Pretest probability 1 0 0 0 0 0 0
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What do you do?

• No test
• No treat no antibiotics
• Treat symptoms

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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

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Case 5
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Peritonsillar Abscess
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Peritonsillar Abscess
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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 39 100/65 P 100
• neck - bilateral enlarged tender anterior
  cervical nodes and smaller posterior cervical
  adenopathy
• lymph nodes axillary adenopathy
• lungs - clear
• abd - no splenomegaly

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Case 6
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Differential Diagnosis

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

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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

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Case 7
deep erythema, palatal petechiae and no exudate,
tonsillar swelling present
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How many points does our patient have?
Fever over 38 C Absence of cough Tender ant. cervical adenopathy Tonsillar swelling or exudate Agelt 15 y Agegt 45 Total 4 Pretest probability 51 1 1 1 1 0 0
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www.med.sc.edu85/ fox/strep-thr.jpg
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Strep Throat
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Candida in aman with AIDS
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Viral
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Herpangina
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Coxsackie A16 Virus
www.netwave.or.jp/jibika/ herpangina.jpg
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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

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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

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Useful web sites

• MedRules has the pharyngitis prediction rule
• http//www.palmgear.com/index.cfm?fuseactionsoftw
  are.showsoftwareprodid10959
• Or get it at Ectopic Brain, a great site for
  other PDA software
• http//pbrain.hypermart.net/