GP196\u2005The use of a rapid antigen detection test for beta haemolytic group a streptococcus to aid the management of pharyngitis and tonsillitis in an irish tertiary paediatric emergency department

Abstract

Background Acute sore throat is a common presentation to the Emergency Department (ED). Rapid-antigen detection testing (RADT) is used in our department to aid diagnosis of Group A streptococcus (GAS) as the cause of pharyngitis/tonsillitis as an adjunct to clinical assessment. Our aims were to assess use of RADT in management and treatment of pharyngitis/tonsillitis in the ED and compare our practice with current NICE guidelines. Methods This was a prospective study which took place at the Children’s University Hospital Dublin in 2018. A proforma was created and doctors were asked to complete this for children who had a RADT for GAS. Data collected included patient age, history, examination findings, rapid-antigen swab result, use of throat swab culture, use of antibiotics.The modified Centor score (MCS) was then calculated. Results Data collected on 102 patients. 1 patient excluded as data form incomplete. 16 (15.8%) patients had low MCS of 0,1 or 2. Of these, 1 patient was RADT positive and treated with antibiotics. 85 (84.2%) patients had high MCS of 3, 4 or 5. 26 (30.6%) were RADT positive and were treated with antibiotics. 59 (69.4%) were RADT negative –6 were treated with antibiotics. Of the 74 patients with a negative RADT, 20 of these had a throat culture sent. 25% had GAS positive culture. 42/101 patients were treated with antibiotics. 27 of these were RADT positive. Of the RADT negative patients, 8 were treated with antibiotics by the ED physician for pharyngitis/tonsillitis, 3 were treated for other diagnoses, 4 had antibiotics continued that were started by a primary care physician. Of the 27 children with a positive RADT swab, 92.5% had a MCS of 4 or 5. Conclusions NICE guidelines suggest no benefit of RADT testing over clinical scores alone. The low incidence of RADT positivity in the low risk MCS group (MCS 0,1 or 2) suggests we can safely not test and not offer antibiotics to these children. In the high MCS group (MCS 3, 4 or 5), only 37.6% of patients had antibiotics started by the ED physician suggesting that RADT may have a role in reducing the number of patients treated with antibiotics. A formal guideline will be created for use in our ED. In communities where the incidence of rheumatic fever is low, a balance must be made between reducing symptoms by a modest amount and the emerging issue of antimicrobial resistance.