dr. simon benson gp specialist trainee. introduction diagnosis of pneumonia in children with wheeze...
TRANSCRIPT
Dr. Simon BensonGP Specialist Trainee
IntroductionDiagnosis of pneumonia in children with
wheeze is difficultLimited data exists regarding predictors of
pneumonia among children with wheezeAsthma and bronchiolitis are two of the
commonest presentations to ED – difficult to distinguish these from those with pneumonia
Result is unnecessary chest radiographs (CXR)
ObjectivesInvestigate value of historical features
andclinical findings in patients with wheeze on examination for whom a CXR was ordered
To develop a clinical decision rule for the use of CXR in this patient population
Study DesignProspective cohortInclusion criteria
Children less than 21 years old Wheezing on examination CXR performed Attending ED between 01/10/2006 and 30/10/2007 Attending Children’s Hospital Boston, Boston MA,
USA
Study DesignExclusion criteria
Chronic respiratory illnesses (eg cystic fibrosis) Illnesses that may predispose to pneumonia
(congenital heart disease, sickle cell anaemia, immunosuppression, malignancy)
Other potential causes for wheeze elicited on history (eg trauma or foreign body aspiration)
Study DesignDoctors were orientated to study and
reminded monthlyQuestionnaire completed prior to CXR request
Specific historical features (eg cough, fever, wheeze, chest pain)
Examination findings Level of respiratory distress Reason for requesting CXR Response to inhaled bronchodilators
Some basic observations were also recorded (Temp, RR, oxygen saturations)
Study DesignCXRs were read by two blinded
radiographersAsked to decide whether normal or abnormalIf abnormal were findings more or less likely
to be caused by atelectasis or pneumoniaIf they failed to agree – original report used
as final diagnosis.
Control group used to assess sample bias was drawn from all patients receiving CXR for first 3 days of each month
Results540 patients included initially
14 excluded due to chronic illness
526 patients included in the study 59% were male Median age 1.9 years (IQ range 0.7-4.5)
47% of patients had a past medical history of wheeze
15% received antibiotics
5% patients were diagnosed with pneumonia
Results81% patients with pneumonia had a history of
fever73% patients with pneumonia had temp > 38.0
in ED Compared to 38% without
Those patients presenting with a fever or history of a fever had were twice as likely to have pneumonia but this increased to nearly five times more likely if a temperature of over 39.0 was recorded in ED
All these results are significant
ConclusionRadiographic pneumonia in children with
wheeze is uncommonHistorical and clinical features may be used
to determine the suitability of CXR in a patient presenting with wheeze
Routine use of CXR for children with wheezing but without fever should be discouraged.
DiscussionIncludes children with asthmaSupports previous workIncluded children up to age 21 – extrapolation by
age group is very difficult – anatomy and physiology vastly different at each end of spectrum
Busy emergency department – how many lost patients (estimated at 39% of all eligible patients)
CXR ordered at discretion of the doctor not according to predefined criteria (introduces selection bias)
DiscussionDid not include outcomes for children with
wheeze who did not have a CXR – can not generalise to all children with wheeze
Likely overestimation of rate of pneumonia in wheeze
Viral versus bacterialSome disagreement between radiologists did
occur – could have used WHO guidelines for radiographic diagnosis of pneumonia but this may not apply with wheezing because of the presence of atelectasis
Final ThoughtsGenerally good paperGenerally good quality and reliable resultsEnables a solid evidence based conclusion to
be drawn that is:Routine use of CXR for children with wheezing
but without fever should be discouraged.