Validation of two algorithms for managing children with a non-blanching rash

Invasive bacterial infection in children with fever and petechial rash in the emergency department: a national prospective observational study

OBJECTIVE

To determine the incidence and clinical predictors of invasive bacterial infection (IBI) in well-appearing children who present to the emergency department (ED) with fever and petechiae.

DESIGN

A prospective, observational, multicentre study was conducted in 18 hospitals between November 2017 and October 2019.

PATIENTS

A total of 688 patients were recruited.

MAIN OUTCOME MEASURES

The primary outcome was the presence of IBI. Clinical features and laboratory test results were described and related to the presence of IBI.

RESULTS

Ten IBIs were found (1.5%), comprising eight cases of meningococcal disease and two of occult pneumococcal bacteraemia. Median age was 26.2 months (IQR 15.3-51.2). Blood samples were obtained from 575 patients (83.3%). Patients with an IBI had a shorter time from fever to ED visit (13.5 hours vs 24 hours) and between fever and rash onset (3.5 hours vs 24 hours). Values for absolute leucocyte count, total neutrophil count, C reactive protein and procalcitonin were significantly higher in patients with an IBI. Significantly fewer patients with a favourable clinical status while in the observation unit were found to have an IBI (2/408 patients, 0.5%) than when clinical status was unfavourable (3/18, 16.7%).

CONCLUSIONS

The incidence of IBI among children with fever and petechial rash is lower than previously reported (1.5%). The time from fever to ED visit and to rash onset was shorter in patients with an IBI. Patients with a favourable clinical course during observation in the ED are at lower risk of IBI.

Loop-mediated isothermal amplification for the early diagnosis of invasive meningococcal disease in children

BACKGROUND

Rapid molecular diagnostic testing has the potential to improve the early recognition of meningococcal disease (MD). The aim of this study was to report on the diagnostic test accuracy of point-of-care loop-mediated isothermal amplification (LAMP) in the diagnosis of MD.

DESIGN

Data were collected prospectively from three UK emergency departments (ED) between November 2017 and June 2019. Consecutive children under 18 years of age attending the ED with features of MD were eligible for inclusion. The meningococcal LAMP test (index test) was performed on a dry swab of the child's oropharynx. Reference standard testing was the confirmation of invasive MD defined as positive N. meningitidis culture or PCR result from a sterile body site (blood or cerebrospinal fluid).

RESULTS

There were 260 children included in the final analysis. The median age was 2 years 11 months and 169 (65%) children were aged 5 years or younger. The LAMP test was negative in 246 children and positive in 14 children. Of the 14 children with positive LAMP tests, there were five cases of invasive MD. Of the 246 children with negative LAMP tests, there were no cases of invasive MD. The sensitivity of LAMP testing was 1.00 and the specificity was 0.97. The negative and positive predictive values were 1.00 and 0.36, respectively. The positive likelihood ratio was 28.3.

DISCUSSION

Non-invasive LAMP testing using oropharyngeal swabs provided an accurate fast and minimally invasive mechanism for predicting invasive MD in this study.

TRIAL REGISTRATION NUMBER

NCT03378258.

Validating clinical practice guidelines for the management of children with non-blanching rashes in the UK (PiC): a prospective, multicentre cohort study

BACKGROUND

No previous studies have validated current clinical practice guidelines for the management of non-blanching rashes in children who have received meningococcal B and C vaccinations. The aim of this study was to evaluate the performance of existing clinical practice guidelines in the diagnosis of invasive meningococcal disease in children presenting with a fever and non-blanching rash in the UK.

METHODS

The Petechiae in Children (PiC) study was a prospective, multicentre cohort study involving children (aged <18 years) presenting to 37 paediatric emergency departments in the UK with a fever (≥38°C) and a new-onset non-blanching rash or features suggestive of meningococcal infection. Children with pre-existing haematological conditions (ie, haematological malignancy, idiopathic thrombocytopenic purpura, or coagulopathy) or an existing diagnosis of Henoch-Schonlein purpura were excluded. Invasive meningococcal disease was confirmed by positive culture or a quantitative PCR test for Neisseria meningitidis from either blood or cerebrospinal fluid samples. The primary outcome was the performance of six tailored clinical practice guidelines from participating centres (London, Nottingham, Newcastle-Birmingham-Liverpool, Glasgow, Chester, and Bristol) and two clinical practice guidelines from the National Institutes for Health and Care Excellence (NICE; CG102 and NG51) in identifying children with invasive meningococcal disease, assessed by the sensitivity and specificity of each clinical practice guideline. This study is registered with ClinicalTrials.gov, NCT03378258.

FINDINGS

Between Nov 9, 2017, and June 30, 2019, 1513 patients were screened, of whom 1329 were eligible and were included in the analysis. The median age of patients was 24 months (IQR 12-48). 1137 (86%) of 1329 patients had a blood test and 596 (45%) received parenteral antibiotics. 19 (1%) patients had confirmed meningococcal disease. All eight clinical practice guidelines had a sensitivity of 1·00 (95% CI 0·82-1·00) for identifying meningococcal disease. The specificities of NICE guidelines CG102 (0·01 [95% CI 0·01-0·02]) and NG51 (0·00 [0·00-0·00]) for identifying meningococcal disease were significantly lower than that of tailored clinical practice guidelines (p<0·0001). The best performing clinical practice guidelines for identifying meningococcal disease were the London (specificity 0·36 [0·34-0·39]) and Nottingham (0·34 [0·32-0·37]) clinical practice guidelines.

INTERPRETATION

Invasive meningococcal disease is a rare cause of non-blanching rashes in children presenting to the emergency department in the UK. Current NICE guidelines perform poorly when compared with tailored clinical practice guidelines. These findings suggest that UK national guidance could be improved by shifting towards a tailored approach.

FUNDING

Public Health Agency.

Parents' and clinicians' views on conducting paediatric diagnostic test accuracy studies without prior informed consent: qualitative insight from the Petechiae in Children study (PiC)

OBJECTIVE

The Petechiae in Children (PiC) study assesses the utility of presenting features and rapid diagnostic tests in the diagnosis of serious bacterial infection in feverish children with non-blanching rashes. An embedded qualitative study explored parents' and clinicians' views on the acceptability of the PiC study, including the use of research without prior consent (RWPC) in studies of diagnostic test accuracy.

DESIGN

Semistructured qualitative interviews. Analysis was thematic and broadly interpretive, informed by the constant comparative approach.

PARTICIPANTS

Fifteen parents were interviewed 55 (median) days since their child's hospital attendance (range 13-95). Five clinicians involved in recruitment, and consent were interviewed.

RESULTS

Parents and clinicians supported RWPC for the PiC study and future emergency paediatric diagnostic test accuracy studies as long as there is no harm to the child and emergency care is not delayed. Parents and clinicians made recommendations around the timing and conduct of a consent discussion, which were in line with RWPC guidance. Parents enrolled in the PiC study preferred a design that included consent discussions with the research team over the alternative of 'opt-out' consent only.

CONCLUSIONS

This embedded qualitative study demonstrates that RWPC is appropriate for use in paediatric emergency studies of diagnostic test accuracy and that the approach used in PiC was appropriate. Future diagnostic studies involving additional invasive procedures or an opt-out only approach to consent would benefit from exploring parent and clinician views on acceptability at the pretrial stage.

TRIAL REGISTRATION NUMBER

NCT03378258.

A systematic review of the diagnostic accuracy of Loop-mediated-isothermal AMPlification (LAMP) in the diagnosis of invasive meningococcal disease in children

BACKGROUND

The early recognition of meningococcal disease in children is vital. During the prodrome however, meningococcal infection presents similarly to many self-limiting viral infections. This mandates a cautious approach with many children receiving unnecessary broad-spectrum parenteral antibiotics. Advances in nucleic acid amplification techniques mean that it is now possible to test for Neisseria meningitidis DNA using Loop-mediated-isothermal AMPlification (LAMP). This technique is quicker than traditional PCR techniques and can be performed using simple equipment.

METHODS

Prior to performing this systematic review, a protocol was developed adhering to PRISMA P standards and underwent full external peer review. This systematic review was registered with PROSPERO (CRD42017078026). The index test assessed was LAMP for Neisseria meningitidis and the reference standard was culture or qPCR of a sterile site detecting Neisseria meningitidis.

RESULTS

We identified 95 records in total: 94 records from the electronic databases and 1 additional study from the grey literature. After removal of duplicates, 36 studies were screened, and 31 studies excluded based on the title/abstract. Five full text studies underwent full text review and three studies, including 2243 tests on 1989 patients aged between 7 days and 18 years were included in the final systematic review. In all studies the LAMP assay and qPCR primers were directed against the ctrA region of the Neisseria meningitidis bacteria. The diagnostic accuracy of LAMP testing for invasive meningococcal disease was reported as high (sensitivity 0.84-1.0 and specificity 0.94-1.0) in all studies irrespective of the sample tested (CSF, Blood, Swab).

CONCLUSIONS

We included three studies with 2243 tests on 1989 patients using CSF, blood samples or naso/oropharyngeal swabs. The studies were all of a high quality and deemed at low risk of bias. Results show that LAMP testing on blood and CSF was highly accurate when compared to qPCR/culture. LAMP testing for Neisseria meningitidis is fast and highly accurate and therefore has the potential to be used to rapidly rule in/out meningococcal disease in children. Given the life-threatening nature of meningococcal infection further research is required to demonstrate the safety and efficacy of using LAMP testing for Neisseria meningitidis as a rule in/out test.

TRIAL REGISTRATION

This systematic review was registered prospectively with PROSPERO on the 29/11/2017 (CRD42017078026).

The "Petechiae in children" (PiC) study: evaluating potential clinical decision rules for the management of feverish children with non-blanching rashes, including the role of point of care testing for Procalcitonin & Neisseria meningitidis DNA - a study protocol

Background

Children commonly present to Emergency Departments (ED) with a non-blanching rash in the context of a feverish illness. While most have a self-limiting viral illness, this combination of features potentially represents invasive serious bacterial infection, including meningococcal septicaemia. A paucity of definitive diagnostic testing creates diagnostic uncertainty for clinicians; a safe approach mandates children without invasive disease are often admitted and treated with broad-spectrum antibiotics. Conversely, a cohort of children still experience significant mortality and morbidity due to late diagnosis. Current management is based on evidence which predates (i) the introduction of meningococcal B and C vaccines and (ii) availability of point of care testing (POCT) for procalcitonin (PCT) and Neisseria meningitidis DNA.

Methods

This PiC study is a prospective diagnostic accuracy study evaluating (i) rapid POCT for PCT and N. meningitidis DNA and (ii) performance of existing clinical practice guidelines (CPG) for feverish children with non-blanching rash. All children presenting to the ED with a history of fever and non-blanching rash are eligible. Children are managed as normal, with detailed prospective collection of data pertinent to CPGs, and a throat swab and blood used for rapid POCT. The study is running over 2 years and aims to recruit 300 children.

Primary objective:

Report on the diagnostic accuracy of POCT for (i) N. meningitidis DNA and (ii) PCT in the diagnosis of early MD

Report on the diagnostic accuracy of POCT for PCT in the diagnosis of Invasive bacterial infection

Secondary objectives:

Evaluate the performance accuracy of existing CPGs

Evaluate cost-effectiveness of available diagnostic testing strategies

Explore views of (i) families and (ii) clinicians on research without prior consent using qualitative methodology

Report on the aetiology of NBRs in children with a feverish illness

Discussion

The PiC study will provide important information for policy makers regarding the value of POCT and on the utility and cost of emerging diagnostic strategies. The study will also identify which elements of existing CPGs may merit inclusion in any future study to derive clinical decision rules for this population.

Trial registration

NCT03378258. Retrospectively registered on December 19, 2017.

A protocol for a systematic review of the diagnostic accuracy of Loop-mediated-isothermal AMPlification (LAMP) in diagnosis of invasive meningococcal disease in children

BACKGROUND

Meningococcal disease (MD) is notoriously difficult to diagnose in the early stages of the illness and presents similarly to many self-limiting viral infections. This mandates a cautious approach to diagnosis and initial management of suspected MD with many children receiving precautionary broad-spectrum intravenous antibiotics. Despite this approach, some children are still diagnosed late. In the last 10 years, there have been advances in nucleic acid amplification techniques, and there is now a rapid test that can detect meningococcal DNA in under 30 min. This Loop-mediated-isothermal AMPlification (LAMP) technology may make it possible to diagnose MD at initial presentation thereby greatly improving outcomes and minimising harms through unnecessary treatment. The aim of this systematic review is to determine the diagnostic accuracy of LAMP technology in cases of suspected MD. The review has been registered with PROSPERO [CRD42017078026].

METHODS

To identify relevant studies, we will search MEDLINE, Embase, Web of Science, Scopus and The Cochrane Library. In additional, we will hand-search reference lists and grey literature including contacting the manufacturers of commercially available LAMP tests for MD for any unpublished data. Two reviewers will independently screen study eligibility and extract data. Methodological quality will be assessed, by two authors, according to the revised tool for the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2); any discrepancies will be resolved by a third author. The following test characteristics will be extracted into 2 × 2 tables for all included studies: true positives, false positives, true negatives, and false negatives. Study-specific estimates of sensitivity and specificity with 95% confidence intervals will be displayed in forest plots. To investigate heterogeneity, we will include covariates such as age, sample type, and study type into a bivariate random-effects model.

DISCUSSION

This review will help determine the diagnostic accuracy of LAMP technology in diagnosing MD from blood, CSF and throat swabs in children. The data will help to define where in the diagnostic pathway LAMP could be useful including potential as a point-of-care test for children at first presentation.