Patient is a 12 year old boy with a sore throat. Neighbor boy had strep throat the week before and the patient was exposed at a birthday party. Mom brings him in wondering if he has strep.
History includes a 12 hour fever (no thermometer used) two days prior which disappeared overnight. No headaches, chills, or malaise. Chief complaint is odynophagia. No mucous drip, stuffy nose, ear pain, or cough. Patient is afebrile and on examination has no tonsillar exudate, no erythema of the posterior pharynx. Tympanic membranes clear bilaterally. Only remarkable finding was petechiae of the soft palate.
Preceptor: "Mr. MedZag, what would you say is the likelihood of this child having strep?"
MedZag: "I'd say 20-30%. The fever course was too short, currently afebrile, no tosillar exudate or enlarged lymph nodes."
Preceptor: "WRONG! With the presence of petechiae on the soft palate, I would place his likelihood at over 80%. I might make you print the antibiotics prescription."
Fast forward 15 minutes. Strep test comes back... negative. Score one for the medical student.
The CENTOR score is criteria used to evaulate the pre-test risk of GABHS phayngitis. The patient is given a point for filling any of the following criteria:
:: Febrile (Temp >100F)
:: No cough
:: Swollen anterior lymph nodes
:: Tonsillar exudate/swelling
:: Age 3-14
Little Billy scored a 3 on the CENTOR score, which puts his pre-test probability at... drumroll please... 28-35%. Hey, 5% off ain't bad.