Deciding on antibiotics in sore throat (Centor and FeverPAIN)

What it is

Viral infections account for around 90% of all sore throats. Not every sore throat is even infective: allergies with postnasal drip, snoring and obstructive sleep apnea, and dehydration all give throat pain. The modified Centor score is the tool that decides how likely the sore throat is to be hemolytic GAS, and therefore who is cultured and who is treated.

How it is diagnosed

The modified Centor score is built from four findings and the age:

1. Cough absent: 1 point.
2. History of fever above 38 C: 1 point.
3. Tonsillar exudate: 1 point.
4. Swollen, tender anterior nodes: 1 point.

Age 3-14 adds 1 point, age 15-44 adds 0, and age above 45 takes 1 point away. In communities with moderate levels of strep infection, where 10-20% of sore throats are strep, the score gives the chance that the patient has strep: 1-2.5% at a score of 0, 5-10% at 1, 11-17% at 2, 28-35% at 3, and 51-53% at 4 or more. Three actions are set against it, each under its own scores:

1. At a score of 0 or 1: no culture and no antibiotic.
2. At a score of 2 or 3: culture all, and treat with antibiotics only if the culture is positive.
3. At a score of 4 or more: culture all, and treat with antibiotics on clinical grounds, discontinuing the antibiotics if the culture comes back negative.

Clinical grounds here means a high fever or other indicators that the patient is clinically not well and is presenting early in the course of the illness. It has two limits. It is not applicable to patients under 3 years of age, and it is invalid and should not be used where there is an outbreak or epidemic of illness caused by GABHS in the community. The tests themselves are RADT for GAS and a throat swab with culture, with CBC alongside them.