Sore Throat
Richard Usatine, MD
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
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
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
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
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)
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
Case 1
What is the differential
diagnosis in order of
likelihood?
Strep
Viral
Sensitivity and Specificity
Strep throat+
Strep throat -
sensitivity
A/(A+C)
specificity
D/(D+B)
A true positive
B false positive
C false negative
D true negative
test +
(Hx, PE or lab)
test -
Positive Predictive Value (PPV)
Changes based on the prevalence in the
population
True positives/all positives
Higher prevalence increases the PPV
How well does PE predict strep
throat?
Sensitivity Specificity
Positive
Predictive Value
Anterior Cervical
adenopathy
Tonsillar Exudate
.80
.55
.27
.65
.69
.31
Tonsillar Swelling
.87
.39
.23
Injected Pharynx
.97
.18
.20
How well does history predict strep throat?
Sensitivity Specificity
PPV
enlarged cervical
nodes
strep exposure
.94
.27
.19
.25
.88
.27
absence of cough
.83
.48
.22
absence of
rhinorrhea
fever > 38.3C
.73
.48
.20
.17
.94
.33
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
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
1
1
1
-1
Probability of Strep throat based on
points (pretest probability)
-1 to 0
1
2
3
4 or 5
1%
10%
17%
35%
51%
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
1
0
1
0
0
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
How to swab for rapid strep test or culture.
3 categories
low probability of GABHS - no test, no
treat
intermediate probability - test
high probability - treat, no test
Rapid Strep Test Done
Result for patient in case one:

positive
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
What symptomatic treatment
could you offer the patient?
Acetaminophen
gargling with warm salt water
throat lozenges
fluids, warm or cold, can be soothing
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 nonproductive 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
Case 2
mild erythema with cobblestone
appearance of posterior pharynx, left
tonsillar exudate present
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%
0
0
1
1
0
0
Rapid Strep Test Done
Result is negative
Symptomatic treatment
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
Case 3
Scarlet fever
How do we treat this?
What does this have to do with rabbits?
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
Case 4
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%
0
0
0
0
0
0
What do you do?
No test
No treat – no antibiotics
Treat symptoms
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
Case 5
Peritonsillar Abscess
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
Case 6
Differential Diagnosis
Mononucleosis
Strep Throat
Viral
Consider a CBC and a monospot.
EBV VCA-IgM is more sensitive but more
expensive.
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
Case 7
deep erythema, palatal
petechiae and no
exudate, tonsillar
swelling present
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
1
1
1
0
0
www.med.sc.edu:85/ fox/strep-thr.jpg
Strep Throat
Candida in a
man with AIDS
Viral
Herpangina
Coxsackie A16 Virus
www.netwave.or.jp/~jibika/ herpangina.jpg
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
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
Useful web sites:
MedRules has the pharyngitis prediction
rule:
http://www.palmgear.com/index.cfm?fuseacti
on=software.showsoftware&prodid=10959
Or get it at Ectopic Brain, a great site for
other PDA software:
http://pbrain.hypermart.net/