The Liverpool Peritonsillar abscess Score: Development of a predictive score through a prospective multicentre observational study

Abstract

Objectives While uncommon in the population at large, peritonsillar abscess (PTA) is a common subject of ENT referrals. Missed or uncertain diagnosis is a source of concern for non‐specialist referrers. In line with the NHS England Second Sepsis Action Plan, we aimed to develop a predictive score for the presence of PTA. This would help to improve non‐specialist colleagues’ diagnostic certainty as well as to support ENT surgeons’ triage of these referrals. Design Prospective, multicentre observational study. Setting Primary and secondary care. Participants Patients >16 years with symptoms of sore throat. Data We prospectively collected comprehensive data on patient demographics, symptoms and clinical status. We documented whether the patient had aspiration‐proven PTA or not. We performed binary logistic regression analysis, iterative development of a predictive score which we validated internally. Results 100 patients were included (46 PTA and 54 tonsillitis). Five variables added significantly to the logistic regression model: unilateral sore throat; trismus; male gender; pharyngeal voice change; and uvular deviation. Using the odds ratio outputs, we developed the Liverpool Peritonsillar abscess Score (LPS) iteratively. We validated the latest (third) iteration of the LPS internally (ie, on the same sample), yielding sensitivity 96%; specificity 85%; positive predictive value 85%; and negative predictive value 96%. The area under the receiver operating characteristics (AUROC) curve was 0.970. Conclusions We have developed the first predictive score for PTA based on symptoms and signs that do not require the user to have specialist experience. Its high negative predictive value may be particularly helpful to non‐specialist colleagues.

A prospective multicentre external validation study of the Liverpool Peritonsillar abscess Score (LPS) with a no‐examination COVID‐19 modification

“…This observational study benefits from collection of prospective data over a broad geographical area with a pre‐determined sample size. Cohort characteristics are comparable to many other studies of patients with sore throats, and age and gender distributions are similar to the original observational study used to develop the LPS 4,9 . The classification function and AUROC yield high degrees of negative prediction and accuracy, respectively.…”

“…Cohort characteristics are comparable to many other studies of patients with sore throats, and age and gender distributions are similar to the original observational study used to develop the LPS. 4,9 The classification function and AUROC yield high degrees of negative prediction and accuracy, respectively. In developing the LPS, we have tried to use objective measures to ensure that the resulting score is highly reproducible in the hands of many different clinicians, including non-specialists.…”

“…In this study, we have categorised diagnosis into discrete categories of "PTA" or "non-PTA" sore throat to ensure reproducibility and to reduce subjectivity: this is in line with our previous methodology. 4 This is likely to mean that the LPS does not differentiate between peritonsillar cellulitis and tonsillitis (in fact, it is likely that this is also reflected in the relatively lower specificity and PPV of the LPS). The stated aim of the LPS, however, is to avoid a missed diagnosis of PTA rather than to differentiate between tonsillitis and peritonsillar inflammatory disease.…”

“…It is therefore important for both non‐specialists and specialists to arrive at the correct diagnosis in order to facilitate early and appropriate treatment. We previously reported the development of a predictive score for peritonsillar abscess through a prospective multicentre observational study (Liverpool Peritonsillar abscess Score, LPS) 4 …”

“…We previously reported the development of a predictive score for peritonsillar abscess through a prospective multicentre observational study (Liverpool Peritonsillar abscess Score, LPS). 4 The LPS is an additive threshold score consisting of five variables with the aim of predicting the likelihood of PTA in adult patients.…”