Clinical Decisionmaking

Use of a clinical algorithm can reduce unnecessary antibiotic use for treatment of sore throat in adults

A majority of adults with sore throat are prescribed antibiotics despite being infected with respiratory viruses which, unlike bacteria, do not respond to antibiotic treatment. Using a simple clinical scoring algorithm (the Centor Criteria), results in about 40 percent of adults getting a test for streptococcal bacteria and fewer than 20 percent getting antibiotics, finds a new study. The algorithm allows clinicians to sufficiently predict the presence or absence of group A b-hemolytic streptococci (GABHS) and avoid prescribing antibiotics to patients unlikely to have strep throat, explains Jeffrey A. Linder, M.D., M.P.H., of Brigham and Women's Hospital.

In evaluating patients with sore throat, the principal goal is identifying patients likely to have GABHS. Only 5 to 15 percent of adult patients seeking care for sore throat are likely to have GABHS. The clinical scoring algorithm known as the "Centor Criteria" consist of four findings that are each assigned one point: history of fever, absence of cough, tender or swollen lymph glands in the neck, and red and swollen tonsils. These criteria are easy to implement and accurately stratify adult patients with suspected GABHS. The recommended algorithm suggests that patients with 0 or 1 finding do not require testing or antibiotics. Patients with 2 or 3 findings should have a rapid strep test (rather than a throat culture) performed, and the results should guide antibiotic treatment. Patients with four findings should receive antibiotics. Throat cultures are not recommended due to the time it takes to get the test results back from the laboratory. Patients with none of the criteria have a 3 percent chance of strep throat while those with all four have a 41 percent chance of the disease.

The author stresses that sore throats can be the result of other causes or infections that may or may not require antibiotics. For example, non-group A streptococci accounts for 5 to 26 percent of patients with sore throat. Other causes include Epstein-Barr virus, Mycoplasma and Chlamydia pneumonia, Neisseria gonorrhea, and Hemophilus influenzae. He also cautions that clinicians who treat patients who might be at risk for undiagnosed or untreated strep infection (such as those with a history of acute rheumatic fever or documented exposure) may want to use a lower threshold for diagnosing and treating GABHS.

The study was supported by the Agency for Healthcare Research and Quality (HS14563).

See "Evaluation and management of adult pharyngitis" by Dr. Linder in the Fall/Winter 2008 Comprehensive Therapy 34(3-4), pp. 196-203.

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