Indian Pediatr 2011;48:
Characteristics of Radiographically Diagnosed
Pneumonia in Under-5 Children in Salvador, Brazil
NK Key, *CA Araújo-Neto, $M-RA Cardoso and CM
From the Departments of Pediatrics, and *Image Diagnosis,
Federal University of Bahia School of Medicine, Salvador; and †Department
of Epidemiology, Faculty of Public Health, University of São Paulo, São
Correspondence to: C M Nascimento-Carvalho, Rua Prof
Aristides Novis, 105/1201B,
Salvador, CEP 40210-630, Bahia, Brazil.
Received: April 12, 2010; Published online: 2011 March 15.
Initial review: May 24, 2010;
Accepted: September 27, 2010.
Objective: To assess the association of demographic and clinical
aspects with radiographically diagnosed pneumonia.
Design: By active surveillance, the admitted
pneumonia cases by the pediatrician on duty were identified in a 2-year
period. Demographic, clinical and radiographic data were registered into
Setting: A public university pediatric hospital in
Salvador, Northeast Brazil.
Patients: Children <5 years-old.
Main outcome measures: Radiographically diagnosed
pneumonia based on detection of pulmonary infiltrate/ consolidation.
Results: 301 cases had the chest X-ray
evaluated by a pediatric radiologist blinded to clinical information,
among whom pulmonary infiltrate and consolidation were described in 161
(54%) and 119 (40%), respectively. Chest X-ray was read normal for
140 cases. Overall, the median age was 17 months (mean 20±14, range 12
days-59 months). Pulmonary infiltrate was less frequently described among
patients aged under 1 year (41.3% vs 59.9%, P=0.002, OR
[95%CI] = 0.47 [0.29–0.76]) and hyperinflation was significantly more
frequent in this age group (27.9% vs 4.1%, P<0.001, OR
[95%CI] = 9.14 [4.0–20.9]). By multiple logistic regression, fever on
admission was independently associated with pulmonary infiltrate (OR
[95%CI] = 1.68 [1.03-2.73]) or consolidation (1.79 [1.10-2.92]), wheezing
was independently associated with absence of pulmonary infiltrate (0.53
[0.33-0.86]) or of consolidation (0.53 [0.33-0.87]). The positive
likelihood ratio of fever on examination for pulmonary infiltrate and
consolidation was 1.49 (95%CI: 1.11–1.98) and 1.49 (95%CI: 1.14-1.94),
Conclusion: Presence of fever enhanced 2.5 times
the chance of children hospitalized with lower respiratory tract disease
to have radiographically diagnosed pneumonia.
Key words: Acute respiratory infection, Brazil, Children,
Pneumonia, Respiratory distress, Wheezing.
cute respiratory infection (ARI)
most common cause of illness in
children, and community-acquired
pneumonia (CAP) is the most serious ARI . The accurate diagnosis of CAP
is an important clinical issue even though it remains difficult .
Evaluation of suspected CAP is a frequent indication for imaging in
children because findings on physical examination are less reliable in
children than in adults. Auscultation and percussion are often harder to
elucidate and evaluate, especially in infants . The roles of imaging in
these children are multiple: confirmation or exclusion of pneumonia,
exclusion of other causes of symptoms, evaluation of cases that fail to
resolve, and evaluation of related complications . Nonetheless,
obtaining a chest X-ray (CXR) is not always feasible .
Therefore, it is of practical usefulness to identify simply recognized
characteristics associated with CAP. Our aim was to assess the association
of demographic and clinical aspects defined a priori, that is age
≥1 year, female gender, report of cough, fever and difficulty
breathing, complete refusal of liquids, detection of fever, tachypnoea,
chest indrawing, somnolence, nasal flaring, cyanosis, reduced pulmonary
sounds, wheezing and crackles, with radiographically diagnosed CAP.
From March 2006 to February 2008, we attempted to
identify the CAP cases among the patients aged less than five years
admitted to the Professor Hosannah de Oliveira Pediatric Center, in
Salvador, North-East Brazil. Demographic and clinical data were registered
into a standardized form by the assistant pediatrician during health
assistance and all CXR were evaluated by the same radiologist who was
blinded to clinical information. CXR was done because of presence of
respiratory complaints or fever on the report from the caregiver, added to
the clinical suspicion of CAP on the evaluation by the assistant
pediatrician based on lower respiratory tract findings on physical
examination. Pneumonia was radiographically defined as presence of
pulmonary infiltrate or consolidation. Pulmonary infiltrate was
defined as linear and patchy densities (interstitial) or dense and fluffy
opacity with or without air-bronchogram (alveolar) out of the hilar area.
Consolidation was defined as alveolar infiltrate that occupies a portion
or whole of a lobe or of the entire lung, and atelectasis as a dense
streak on the film that radiates outward from the hilum . Axillary
temperature was measured by trained nurses before the medical examination
and it was registered on the medical chart. Whenever fever was detected,
the pediatrician repeated the temperature measurement before prescribing
anti-pyretics. Fever was defined as axillary temperature >37.5ºC  and
tachypnea as respiratory rate ≥60
breaths/min in children aged less than 2 months,
³50 breaths/min in
children aged 2-11 months and
breaths/min in children as of 12 months of age .
Nutritional evaluation was performed by using the
software Anthro, version 1.02 (Center for Disease Control and Prevention,
and World Health Organization) and severe malnutrition was defined as Z-score
for weight-for-age index under –3.00 by using the National Centre for
Health Statistics standard . Statistical analyses were performed by
using Statistical Package for the Social Sciences 9.0 and STATA 9.0.
Differences in proportions were assessed by the Pearson Chi Square test or
Fisher’s exact test as appropriate and in continuous variable by the
Student t test or Mann-Whitney U test as appropriate. Bivariate and
multivariate analyses, using logistic regression models, were performed to
identify associations between demographic/clinical aspects and
radiographically diagnosed CAP. The positive likelihood ratio (LR) was
estimated. The 95% confidence intervals (CI) were calculated. Informed
consent was obtained from the patient’s guardian and the study was
approved by the Ethics Committee of the Federal University of Bahia.
Out of 34,533 patients seen at the Emergency Room due
to various complaints, 321 (0.9%) were admitted because of suspected CAP
on the evaluation by the pediatrician on duty. The CXR had been taken and
read by a pediatric radiologist, member of this research project team. Due
to poor CXR quality, 20 (6.2%) cases were excluded. Out of 301 evaluated
cases, detection of pulmonary infiltrate and consolidation was described
in 161 (54%) and 119 (40%) children, respectively. CXR was labelled normal
for the others 140 cases. Among the radiographically confirmed CAP cases,
pulmonary infilterate was described as alveolar (135; 84%), interstitial
(14; 9%), or alveolar-interstitial (12; 7%). Other radiographic findings
among the radiographi-cally confirmed CAP cases were: hyperinflation (37,
23%), atelectasis (36, 22%), peribronchial thicken-ing (31, 19%), pleural
effusion (23, 14%) and pulmonary abscess (2, 1%); there was no
pneuma-tocele or pneumothorax. Overall, the median age was 17 months (12
days - 59 months) and there were 158 (53%) males.
The most frequent complaints reported in the history
were cough (99%), fever (94%), difficulty breathing (77%); and the most
frequent findings on physical examination on admission were tachypnea
(73%), crackles (58%), wheezing (51%), fever (41%) and chest indrawing
(35%). Out of 22 patients without complaint of difficulty breathing or
tachypnea, 6 reported disease longer than 7 days, and crackles (5),
reduced pulmonary sounds (4), chest indrawing (3), somnolence (3) and
wheezing (1) were found. The significant differences found between the
cases with and without pulmonary infiltrates or consolidation are
described in Table I. The frequency of complaint of fever
(96% vs 94%, P = 0.047), difficulty breathing (71% vs
85%, P = 0.003), chest indrawing (30% vs 41%, P =
0.04) and decreased breath sounds (39% vs 21%, P < 0.001)
was significantly different in the bivariate analyses when patients with
and without pulmonary infiltrates were compared but there was no
difference in the multivariate analysis. Likewise, the frequency of
complaint of fever (97% vs 91%, P = 0.03), difficulty
breathing (69% vs 83%, P = 0.004) and decreased breath
sounds (41% vs 24%, P = 0.002) when patients with and
without consolidation were compared. Overall, the positive LR of fever on
examination for pulmonary infiltrates and consolidation was 1.49 (95% CI:
1.11 – 1.98) and 1.49 (95% CI: 1.14 - 1.94), respectively. Likewise, the
positive LR of absence of wheezing for PI and consolidation was 1.45 (95%
CI: 1.14 – 1.86) and 1.43 (95% CI: 1.14 – 1.79), respectively.
TABLE I Significant Differences Between Patients With and Without Pulmonary Infiltrate or
Consolidation on the Chest X-Ray
||(n = 161)
||(n = 140)
||(95% CI) *
||(n = 119)
(95% CI) *
Age ≥1 year
Fever on admission
Results in n (%); *OR adjusted for complaint of fever, difficulty breathing, chest indrawing, decreased breath
sounds and the other variables in the table.
There were no significant differences between patients
with and without PI for the following variables: underlying chronic
illness (10% vs 15%), continuous medicine use (7% vs 10%),
report of cough (99 % vs 99%), complete refusal of liquids (0.6%
vs 0%), duration (days) of illness (8 ± 5 vs 7 ± 5), of fever
(6 ± 4 vs 6 ± 5), of cough (7 ± 6 vs 6 ± 5), presence of
tachypnea (74% vs 71%), severe malnutrition (2% vs 3%),
dehydratation (6% vs 3%), somnolence (22% vs 19%), nasal
flaring (7% vs 6%), cyanosis (0.6% vs 0.7%) and crackles
(57% vs 59%).
Pulmonary infiltrates were less frequently described
among patients aged under 1 year (41.3% vs 59.9%, P=0.002,
OR[95% CI] = 0.47 [0.29-0.76]) and hyperinflation was significantly more
frequent in this age group (27.9% vs 4.1%, P<0.001, OR[95%
CI] = 9.14 [4.0-20.9]). For those patients aged 1 year onwards (n=197),
pulmonary infiltrates was detected in 118 (60%) and it was associated with
decreased breath sounds (45% vs 29%, P=0.03, OR[95%CI] = 2.0
[1.1-3.6]); absence of pulmonary infiltrates was associated with complaint
of difficulty breathing (80% vs 66%, P=0.04, OR [95% CI] =
2.02 [1.04-3.9]) and wheezing (60% vs 35%, P=0.001, OR [95%
CI] = 2.8 [1.5-5.0]).
The study showed that either fever or absence of
wheezing was independently associated with radio-graphically diagnosed
CAP, if the end-point analyzed was presence of pulmonary infiltrate or
consolidation. On the other hand, tachypnea was equally frequent among
patients with and without radiographically diagnosed CAP. These results
are in disagreement with those reported by the earlier studies in which
tachypnoea had been identified as the most sensitive and specific simple
sign to identify CAP among children with ARI and fever was not [8-11]. The
selection of patients in the studies conducted by Shann, et al.
, Campbell, et al. , Cherian, et al.  and Spooner,
et al.  excluded children with wheezing. In these
investigations, the authors concluded that tachypnea was the most
sensitive simple sign to detect lower respiratory compromise among
children with respiratory complaints. As wheezing children were excluded,
the most frequent lower respiratory disease was pneumonia.
Wheezing has been recognized as a confounding variable
in order to distinguish children with CAP and proposals to refine the use
of tachypnea in differentiating asthma form ARI in children have been
published [12,13]. Moreover, wheezing may be present both in children with
asthma or bronchiolitis. The association of absence of pulmonary
infilterates as well as hyperinflation with children aged under 1 year
suggests that brochiolitis was the correct diagnosis of many patients in
this age group, initially diagnosed with suspected CAP by the assistant
pediatrician . Results from a recent study have shown that most
children with tachypnea had normal chest X-ray when children with
wheezing were not excluded . Therefore, it is necessary to implement
additional steps in order to accurately identify children with CAP among
children with respiratory symptoms in daily practice.
In this investigation, the inclusion criteria selected
patients aged <60 months who underwent CXR because of suspicion of
pneumonia by the pediatrician on duty. This strategy selected children
with lower respiratory tract disease. Therefore, the studied group was
different from the other studies which identified tachypnea as the most
sensitive simple sign to detect pneumonia cases.
Fever has been used as a marker for malaria in the
algorithm from the Integrated Management of Childhood Illness from WHO
. Nonetheless such use must be restricted to malaria regions. Where
malaria is less common, fever may be more predictive of infection . In
an urban middle income easy access setting, history of fever at home and
triage temperature ≥38oC
were among the associated findings with pneumonia in wheezing children
. Improving the case management algorithm of childhood CAP at
resource-limited setting has been challenging. A trial of rapid-acting
bronchodilator in children with wheeze and fast breathing has now been
recommended before making a diagnosis of CAP . From the results
presented herein, it is possible to estimate that presence of fever
enhances 2.5 times the chance of children hospitalized with lower
respiratory tract disease to have radiographically diagnosed pneumonia.
Therefore, the presence of fever on physical examination enhanced the
probability of pneumonia among children under 5 years-old with lower
respiratory tract disease and may be useful to distinguish children with
pneumonia from those with other lower respiratory tract diseases. Children
with CAP diagnosed solely based on the detection of tachypnea may receive
It is necessary to highlight the strengths of this
study: first, the whole study was conducted at the same hospital where
health care professional had been trained to identify eligible patients;
second, the same researcher was in charge of compiling the whole data;
third, the use of a strict radiographic criteria used by an experienced
pediatric radiologist blinded to clinical information; and fourth, the
collection of data in daily practice. Nonetheless, the limitations must be
commented on: different observers evaluated the enrolled patients and only
one radiologist read the CXR. Therefore, the results may be used for
Acknowledgments: Pediatricians of the Emergency
Room of the Professor Hosannah de Oliveira Pediatric Center, Federal
University of Bahia, Salvador, Brazil for their cooperation in the
evaluation of the patients.
Contributors: NKK collected the clinical data and
drafted the manuscript; CAA read the chest X-rays, filled the
radiographic forms, took part in the interpretation of the results and
critically the manuscript; M-RAC took part in the analysis and revised the
manuscript; CMN conceived the research question and designed the study
protocol, analyzed the data and revised critically the manuscript. All
authors approved the submitted version.
Funding: Ng K Key was recipient of a fellowship
from the Brazilian Council for Science and Technology Development (CNPq);
Maria-Regina A Cardoso and Cristiana M Nascimento-Carvalho are
investigators of CNPq. CNPq had no role in handling or completing the
research. The authors had full control of all primary data.
Competing interests: None stated.
What is Already Known?
• Tachypnea is the most sensitive simple sign
to detect pneumonia cases among children under 5 years-old with
What This Study Adds?
• Presence of fever enhances the probability of pneumonia 2.5
times among children with lower respiratory tract disease.
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