Our aim was to identify which clinical features have value in confirming or excluding
the possibility of serious infection in children presenting to ambulatory care settings
in developed countries.
In this systematic review, we searched electronic databases (Medline, Embase, DARE,
CINAHL), reference lists of relevant studies, and contacted experts to identify articles
assessing clinical features of serious infection in children. 1939 potentially relevant
studies were identified. Studies were selected on the basis of six criteria: design
(studies of diagnostic accuracy or prediction rules), participants (otherwise healthy
children aged 1 month to 18 years), setting (ambulatory care), outcome (serious infection),
features assessed (assessable in ambulatory care setting), and sufficient data reported.
Quality assessment was based on the Quality Assessment of Diagnostic Accuracy Studies
criteria. We calculated likelihood ratios for the presence (positive likelihood ratio)
or absence (negative likelihood ratio) of each clinical feature and pre-test and post-test
probabilities of the outcome. Clinical features with a positive likelihood ratio of
more than 5.0 were deemed red flags (ie, warning signs for serious infection); features
with a negative likelihood ratio of less than 0.2 were deemed rule-out signs.
30 studies were included in the analysis. Cyanosis (positive likelihood ratio range
2.66-52.20), rapid breathing (1.26-9.78), poor peripheral perfusion (2.39-38.80),
and petechial rash (6.18-83.70) were identified as red flags in several studies. Parental
concern (positive likelihood ratio 14.40, 95% CI 9.30-22.10) and clinician instinct
(positive likelihood ratio 23.50, 95 % CI 16.80-32.70) were identified as strong red
flags in one primary care study. Temperature of 40 degrees C or more has value as
a red flag in settings with a low prevalence of serious infection. No single clinical
feature has rule-out value but some combinations can be used to exclude the possibility
of serious infection-for example, pneumonia is very unlikely (negative likelihood
ratio 0.07, 95% CI 0.01-0.46) if the child is not short of breath and there is no
parental concern. The Yale Observation Scale had little value in confirming (positive
likelihood ratio range 1.10-6.70) or excluding (negative likelihood ratio range 0.16-0.97)
the possibility of serious infection.
The red flags for serious infection that we identified should be used routinely, but
serious illness will still be missed without effective use of precautionary measures.
We now need to identify the level of risk at which clinical action should be taken.
Health Technology Assessment and National Institute for Health Research National School
for Primary Care Research.
Copyright 2010 Elsevier Ltd. All rights reserved.