The aetiology of pharyngotonsillitis in primary health care: a prospective observational study
Open Access
- 17 September 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in BMC Infectious Diseases
- Vol. 21 (1), 1-11
- https://doi.org/10.1186/s12879-021-06665-9
Abstract
Few studies on pharyngotonsillitis have examined the clinical presentation of different aetiologies where pathogens have been detected using molecular methods. We aimed to assess how well clinical signs and symptoms can predict (1) the presence or absence of a broad range of viruses and bacteria, and (2) reconsultations for a sore throat or a complication. In this descriptive observational prospective study in primary health care 220 patients aged 15–45 with suspected pharyngotonsillitis were sampled from nose, throat and blood and screened for 20 bacteria and viruses using polymerase chain reaction (PCR), culture and serology. Odds ratios (OR) and predictive values with 95% confidence intervals (CI) were used to show association between microbiological findings and clinical signs and symptoms. Patients were followed up after 3 months by reviewing electronic medical records. Both cough and coryza were more common in patients with only viruses (67%) than in patients with only bacteria (21%) (p < 0.001), whereas tonsillar coating was more common in patients with only bacteria (53%) than in patients with only viruses (29%) (p = 0.006). Tonsillar coating (adjusted OR 6.0; 95% CI 2.5–14) and a lack of cough (adjusted OR 3.5; 95% CI 1.5–8.0) were significantly associated with Streptococcus pyogenes (group A streptococci; GAS) and with any bacterial finding. A Centor score of 3–4 had a positive predictive value of 49% (95% CI 42–57) for GAS and 66% (95% CI 57–74) for any bacterial findings. The use of rapid antigen detection test for GAS increased the positive predictive value for this group to 93%. Signs and symptoms, both single and combined, were insufficient to rule in GAS or other pathogens. However, both cough and coryza were useful to rule out GAS. The results support the clinical approach of restricting rapid antigen detection testing to patients with 3–4 Centor criteria. The low carriage rate of bacteria among asymptomatic controls implied that most detections in patients represented a true infection.Funding Information
- Region Kronoberg
- The Nordic Society of Clinical Microbiology and Infectious diseases
- The South Swedish Region Council
- Lund University
This publication has 33 references indexed in Scilit:
- PRImary care Streptococcal Management (PRISM) study: identifying clinical variables associated with Lancefield group A β-haemolytic streptococci and Lancefield non-Group A streptococcal throat infections from two cohorts of patients presenting with an acute sore throatBMJ Open, 2013
- Spectrum and Inoculum Size Effect of a Rapid Antigen Detection Test for Group A Streptococcus in Children with PharyngitisPLOS ONE, 2012
- Large-Scale Validation of the Centor and McIsaac Scores to Predict Group A Streptococcal PharyngitisJAMA Internal Medicine, 2012
- Predicting streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor scoreBMC Medicine, 2011
- Prevalence of Streptococcal Pharyngitis and Streptococcal Carriage in Children: A Meta-analysisPEDIATRICS, 2010
- Pragmatic Scoring System for Pharyngitis in Low-Resource SettingsPEDIATRICS, 2010
- The Human Immune Response to Streptococcal Extracellular Antigens: Clinical, Diagnostic, and Potential Pathogenetic ImplicationsClinical Infectious Diseases, 2010
- Confidence intervals for predictive values with an emphasis to case–control studiesStatistics in Medicine, 2007
- The predictive value of microbiologic diagnostic tests if asymptomatic carriers are presentStatistics in Medicine, 2002
- Upper Respiratory Tract Infections in General Practice: Diagnosis, Antibiotic Prescribing, Duration of Symptoms and Use of Diagnostic TestsScandinavian Journal of Infectious Diseases, 2002