Algorithm

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	The Medical Algorithms Project =

Chapter :

ch23. Microbiology & Infectious Diseases

Section :

Infections by Group A Streptococcus =

Sore Throat=20 Score of McIsaac et al

Excel=20 Sheet

Reference

Score

Streptococcal=20 Pharyngitis is:

Percent = Positive=20 Cultures (Breese = Data)

18 25

unlikely

6.1%

26 29

maybe not

36.0%

30 31

maybe

56.4%

32 - 38

probably

84.4%

Parameter

Finding

Points

month of the year

February, March, = April

January, May, = December

June, October, = November

July, August, = September

age in years

<=3D 2

5 10

11 14

>=3D 15

WBC count

unknown

<=3D 8,400 per L

8,500 10,400 per L

10,500 13,400 per L

13,500 20,400 per L

>=3D 20,500

body temperature

>=3D 100.5F (fever = present)

< 110.5F

unknown

sore throat

yes

unknown

cough

yes

unknown

headache

yes

unknown

abnormal pharynx

yes

unknown

abnormal cervical lymph = nodes=20 (glands)

yes

unknown

Overview :

Breese developed a scorecard with = 9 items to=20 aid in the diagnosis of Streptococcal pharyngitis. The = author=20 was from the University of Rochester in New York.

Parameters used for score:

(1) month of the year

(2) age

(3) WBC count

(4) body temperature

(5) sore throat

(6) cough

(7) headache

(8) abnormal pharynx

(9) abnormal cervical glands

score =3D

=3D SUM(points for all 9 = factors)

Interpretation:

minimum score: 14

maximum score: 38

Higher=20 scores are associated with a higher probability of a = positive=20 Streptococcal Group A isolate.

from Table 1, page 516

Performance:

In = Breese's=20 study the streptococcal prevalence was 54% and the = scorecard=20 gave results comparable to the physician diagnosis. = The=20 physician was correct in 79.4% of cases while the = scorecard=20 was correct in 77.8%.

Reed et al=20 found the score to have a sensitivity of 26%, = specificity of=20 94%, positive predictive value of 58% and a negative=20 predictive value of 79% in a population of children = with a=20 streptococcal prevalence of 25%. Use of the score with = a rapid=20 antigen detection test did not improve the accuracy of = either=20 test significantly, and culture was felt to still be=20 necessary.

Breese also describes a 13 factor = scorecard=20 which did not show greater accuracy than the 9 factor=20 scorecard. This included the addition of:

(10) running nose

(11) diarrhea

(12) abnormal lungs

(13) abnormal ears.

Reference

Breese BB. A=20 simple scorecard for the tentative diagnosis of = streptococcal=20 pharyngitis. Am J Dis Child. 1977; 131: 514-517.

Ebell MH,=20 Smith MA, et al. Does this patient have Strep throat? = JAMA.=20 2000; 284: 2912-2918.

Funamura JL,=20 Berkowitz CD. Applicability of a scoring system in the = diagnosis of streptococcal pharyngitis. Clinical = Pediatrics.=20 1983; 22: 622-626.

Reed BD,=20 Huck W, French T. Diagnosis of Group A beta-hemolytic=20 Streptococcus using clinical scoring criteria, = directigen=20 1-2-3 Group A Streptococcal test, and culture. Arch = Intern=20 Med. 1990; 150: 1727-1732.

=20 Excel Sheet |

Reference

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