Qualitative Research
Separate each section in your paper with a clear heading that allows your professor to know which bullet you are addressing in that section of your paper. Support your ideas with at least one (1) source using citations in your essay. Make sure to cite using the APA writing style for the essay. The cover page and reference page are required. Review the rubric criteria for this assignment.
Conduct a literature search to select a qualitative research study on the topic identified in Module 1. Conduct an initial critical appraisal of the study.
RESEARCH STUDY IS ATTACHED
Respond to the overview questions for the critical appraisal of qualitative studies, including:
- What type of qualitative research design was utilized to conduct the study?
- Are the results valid/trustworthy and credible?
- How were the participants chosen?
- How were accuracy and completeness of data assured?
- How plausible/believable are the results?
- Are implications of the research stated?
- May new insights increase sensitivity to others’ needs?
- May understandings enhance situational competence?
- What is the effect on the reader?
- Are the results plausible and believable?
- Is the reader imaginatively drawn to the experience?
- What are the results of the study?
- Does the research approach fit the purpose of the study?
- How does the researcher identify the study approach?
- Are the data collection and analysis techniques appropriate?
- Is the significance/importance of the study explicit?
- Does the literature support a need for the study?
- What is the study’s potential contribution?
- Is the sampling clear and guided by study needs?
- Does the researcher control selection of the sample?
- Do sample size and composition reflect the study needs?
- Is the phenomenon (human experience) clearly identified?
- Are data collection procedures clear?
- Are sources and means of verifying data explicit?
- Are researcher roles and activities explained?
- Are data analysis procedures described?
- Does analysis guide directions of sampling when it ends?
- Are data management processes described?
- What are the reported results (descriptive or interpretation)?
- How are specific findings presented?
- Are the data meanings derived from data described in context?
- Does the writing effectively promote understanding?
- Will the results help me care for my patients?
- Are the results relevant to persons in similar situations?
- Are the results relevant to patient values and/or circumstances?
- How may the results be applied to clinical practice?
Assignment Expectations:
Length: Clearly and fully answer all questions; attach a copy of the article
Structure: Include a title page and reference page in APA format. Your essay must include an introduction and a conclusion.
References: Use appropriate APA style in-text citations and references for all resources utilized to answer the questions. A minimum of one (1) scholarly source for the article is required for this assignment.
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Therapeutics and Clinical Risk Management 2017:13 847–
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O R i g i n a l R e s e a R C h
open access to scientific and medical research
Open access Full Text article
http://dx.doi.org/10.2147/TCRM.S134153
Diagnostic reliability of pediatric appendicitis
score, ultrasound and low-dose computed
tomography scan in children with suspected
acute appendicitis
ashraf Othman sayed1
nancy selim Zeidan2
Dalia Monir Fahmy3
hossam a ibrahim4
1Department of Pediatrics, Children
and Women’s University hospital,
Minia University, el-Minya, egypt;
2Department of Pediatrics, Faculty
of Medicine, Cairo University,
Cairo, egypt; 3Department of
Diagnostic Radiology, Mansoura
University hospital, Faculty of
Medicine, Mansoura University,
Mansoura, egypt; 4Department of
surgery, Faculty of Medicine, Cairo
University, Cairo, egypt
Background: Diagnosis of appendicitis in children is clinically challenging. Computed
tomography (CT) is the gold standard for diagnosis; however, radiation exposure early in life
is a concern with this technique. Therefore, in this study, we aimed to evaluate the diagnostic
reliability of low-dose CT, pediatric appendicitis score (PAS), and abdominal ultrasound (US)
in children with acute appendicitis, to reach a safe diagnosis.
Patients and methods: This retrospective study was conducted on 140 children who
were admitted with clinically suspected acute appendicitis (45 with positive appendicitis and
95 children with negative appendicitis). Low-dose CT was performed, and PAS was retro-
spectively calculated for all subjects. US was initially performed for 38 subjects. All results
were compared with the final diagnosis reached by an operative, histopathological analysis
and follow-up.
Results: Low-dose CT showed a sensitivity, specificity, and accuracy of 97.8%, 100%, and
99.3%, respectively. At a cutoff value $5, PAS showed a sensitivity, specificity, and accuracy
of 95%, 84%, and 89%, respectively. Abdominal US examination showed sensitivity, specificity,
and accuracy of 55.6%, 85%, and 71%, respectively. Implementing Poortman’s model resulted
in higher accuracy (92%) of US. There was a significant difference in accuracy between a
low-dose CT and PAS on one side and between Poortman’s model and US examination on the
other side. A diagnostic scheme was suggested using PAS as the excluding tool (PAS #2 send
home and $7 send directly to operation) followed by US examination and reserving low-dose
CT for inconclusive cases. This scheme would eliminate the use of CT for at least 33.7% and
in 7 cases who had initial US examination.
Conclusion: Although CT remains the most accurate and less operator-dependent diagnostic
tool for pediatric appendicitis, the radiation hazards could however be minimized using PAS
as an excluding tool and US as the primary imaging modality followed by low-dose CT for
inconclusive cases only.
Keywords: acute appendicitis, children, pediatric appendicitis scoring system, PAS, computed
tomography, CT, ultrasound, US
Introduction
Acute appendicitis remains the most common acute surgical condition in children
and a major cause of morbidity; appendectomy is still the mainstay of treatment.1
Delayed intervention leads to dramatic complications such as perforation and abscess
formation while rushing to surgery is associated with a high negative appendectomy
Correspondence: Dalia Monir Fahmy
Department of Diagnostic Radiology,
Faculty of Medicine, Mansoura
University hospital, Mansoura
University, el-gomhoria street,
Mansoura, 35516, egypt
Tel +20 109 104 3679
Fax +20 50 229 5025
email daliamonir2525@gmail.com
Journal name:
Therapeutics and Clinical Risk Management
Article Designation: Original Research
Year: 2017
Volume: 13
Running head verso: Sayed et al
Running head recto: Reliability of PAS, US, and CT in the diagnosis of pediatric appendicitis
DOI: http://dx.doi.org/10.2147/TCRM.S134153
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sayed et al
of up to 15%–30%.2 Diagnosis of appendicitis in children is
challenging, not only because there are so many other non-
surgical conditions that mimic appendicitis,1 but also because
there are difficulties in communication and examination.3
In many hospitals, including ours, pelvic–abdominal
computed tomography (CT) is considered the gold standard
diagnostic tool for the diagnosis of appendicitis in children
owing to its high sensitivity and specificity.4 CT scan has
certainly saved a significant number of patients from under-
going unnecessary surgeries but has also caused unnecessary
radiation exposure in them. Recent studies have reported that
the risk of radiation exposure early in life is up to 25 mSv
per study, which has raised concern regarding the increased
incidence of cancer in pediatric patients.5,6 Another study
predicted that approximately 29,000 future cancer cases will
be linked to CTs performed in the year 2007, with the largest
proportion coming from pelvic–abdominal scans.7 Therefore,
in order to decrease radiation exposure, several protocols of
modified technical parameters (tube voltage, tube current,
and slice thickness) have been implemented.8
Graded compression abdominal ultrasound (US) is a
widespread bedside examination tool which costs less than
CT and poses no radiation hazards but has low sensitivity and
is operator-dependent. Pediatric appendicitis score (PAS) is
a commonly cited appendicitis clinical scoring system that
was developed specifically for children by Samuel.9 To our
knowledge, there are no previously published studies that
investigated PAS performance in comparison to abdominal
US and low-dose CT in our region.
Therefore, we aimed to evaluate the diagnostic reliability
of low-dose CT, PAS, and abdominal US examination in
children with suspected acute appendicitis, in order to reach
a safe diagnosis with less radiation hazard.
Subjects and methods
Design and study population
This is a retrospective cross-sectional study conducted over
18 months from March 2015 to September 2016 at a major
urban institution. Ethical approval from the Ethic Committee
of Dar Al-Shifa Hospital was obtained for this study. The
committee waived the need for an informed patient consent
(from parent or guardian) owing to the retrospective nature
of the research and as it did not seem to jeopardize patient
confidentiality, privacy, or safety.
inclusion criteria
All children of both sexes between the age of 4 and 18 years
who were admitted with clinically suspected acute appendi-
citis were included in this study.
exclusion criteria
Children aged below 4 or above 18 years at the time of
operation, or with incomplete medical records, or those
who underwent appendectomy incidentally, or with chronic
abdominal pain were excluded from this study.
Result comparison with final diagnosis
The PAS and imaging (CT and US) results were compared
with the final diagnosis reached by surgery and histopatho-
logical analysis or by follow up.
Clinical and laboratory assessment
The following data were collected from the automated and
nonautomated medical records in the hospital: age, gender,
duration of abdominal symptoms (days), and weight (kg).
PAS values were calculated retrospectively for each
patient according to the original PAS definition.9 The
8 components of PAS are as follows: fever, anorexia, nausea/
vomiting, migration of the pain to the right lower quadrant
(RLQ), tenderness on light palpation of RLQ, cough/
percussion/heel tapping tenderness at the RLQ, leukocytosis,
and polymorphonuclear neutrophilia; all components of
PAS were scored 1 point, except, right quadrant tenderness
and cough/percussion/heel tapping tenderness were scored
2 points (Table 1). Clinical assessment was performed by
licensed pediatricians in the emergency room upon the initial
admission of the patients.
Radiological imaging
Computed tomography
All subjects (n=140) included in this study had CT examina-
tion of the abdomen and pelvis, which was performed after
fasting for at least 4 hours prior to scanning. Our protocol
included intake of 1,000 mL of oral contrast solution (non-
ionic) over a period of 90 min, followed by pre- and post-
contrast phase (venous). However, in certain circumstances,
such as severe vomiting or urgent cases that were planned for
Table 1 Components of pediatric appendicitis score
Signs/symptoms Point
value
nausea/emesis 1
anorexia 1
Migration of pain to RlQ 1
low-grade fever ($38.0°C) 1
RlQ tenderness on light palpation 2
Cough/percussion/heel tapping tenderness at RlQ 2
leukocytosis (.10,000/mm3) 1
left shift (.75% neutrophilia) 1
Total 10
Abbreviation: RlQ, right lower quadrant.
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Reliability of Pas, Us, and CT in the diagnosis of pediatric appendicitis
operation soon after CT scan, oral intakes of contrast were
eliminated from our protocol.
CT scan was performed using a Siemens SOMATOM
defined Flash dual source 128 multi-detector scanner
(Siemens Medical Solutions, Forchheim, Germany): tube
voltage, 100 kVp; tube current, 87/190 MA; slice thick-
ness, 6 mm; and 40 mL Xenetix® (Guerbet, Gorinchem, the
Netherlands) at 4 m/s. Postcontrast scan was performed 60 s
after intravenous injection of Xenetix 350. The low-dose
technique was implemented and a size-specific dose estimate
(SSDE), an approximation of absorbed dose incorporating
patient diameter, and effective dose (ED) was calculated
for each scan.
image analysis
CT images were reviewed by a senior radiologist (DF) with
15 years’ experience in abdominal imaging, who was blinded
to the clinical findings and laboratory results. The criteria
for diagnosis of acute appendicitis included the following:
swollen appendix (outer diameter exceeding 6 mm) with
or without fecolith, enhanced walls, and peri-appendiceal
strands. The signs of perforation included the following: free
intra-peritoneal air and excess peri-appendiceal, pelvic, or
abdominal fluid. CT findings were interpreted as negative if
an appendix was not visualized, had an outer diameter of less
than 6 mm, and had absence of peri-appendiceal strands.
Ultrasound examination
All US examinations were performed using a curved
3.5–5.0 MHz array and a linear 6 MHz array (ultrasound
machine GE volusone E8 and E10). The criteria for diagno-
sis of acute appendicitis were as follows: local transducer
tenderness, noncompressible appendix, a thickened appendix
(diameter greater than 6 mm), presence of an appendicoliths,
peri-appendiceal fat infiltration, and free fluid adjacent to
the appendix. In addition to a routine abdominal and pelvic
US, all ultrasound examinations were performed in our
institution by licensed general radiologists with at least
5 years’ experience.
Operative and histopathological analysis
Surgery was performed by a consultant general surgeon with
more than 20 years’ of experience. The existence of polymor-
phonuclear leukocytes, lymphocytes, or plasma cells in appen-
diceal biopsy was considered positive for appendicitis.
Negative appendectomy was defined as, 1) an operation
with a preoperative diagnosis of appendicitis, and 2) absence
or minimal acute inflammatory cells in the case of appendec-
tomy, or normal appearance of the appendix.
Follow-up
Patients who had a stable clinical condition and with a nega-
tive CT scan for appendicitis were sent home and received a
follow-up phone call after 1 week to assess their condition
and cessation of symptoms. Patients, who had other diseases
that caused acute abdominal pain other than appendicitis,
discovered by imaging and laboratory tests, were treated
according to their condition, as usual.
statistical analysis
IBM SPSS software package (Statistical Package for Social
Sciences, version 20 for Windows) was used to analyze data.
A 1-sample Kolmogorov–Smirnov test was used to assess
whether the data were normally distributed. Continuous
variables were presented as mean ± standard deviation and
data were compared using an unpaired t-test. Categorical
variables were expressed as numbers and percentages and
analyzed for comparisons using chi-square test.
For evaluating the predictive value of PAS in the diagno-
sis of acute appendicitis, the sensitivity, specificity, positive
predictive value (PPV), negative predictive value (NPV), and
accuracy were calculated. In addition, receiver operating char-
acteristic (ROC) curves were analyzed for the overall PAS
performance. At the 5% level of significance, P-value less
than 0.05 was considered significant in all statistical tests.
Results
A total of 140 patients were included in this study; 45 patients
(positive appendicitis group) had surgery followed by
histopathological analysis that confirmed acute appendi-
citis. None had a negative appendectomy. The remaining
95 patients (negative appendicitis group) had diseases other
than appendicitis that were revealed by CT scan and clinical
follow-up; none of these patients showed any complications
related to a missed diagnosis of appendicitis (Table 2).
Table 2 The final diagnosis in the negative appendicitis group
(n=95)
Diagnosis Number
of cases
Mesenteric lymphadenitis 42
Ovarian cyst 18
Colitis 25
enteritis 4
Crohn’s 1
intestinal obstruction 1
Diverticulitis 1
acute paniculitis 1
gastritis 1
Ureteric stone 1
Total 95
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sayed et al
Out of 140 patients included in this study, 77 were
males and 63 were females. No significant difference was
found between the positive and negative appendicitis groups
regarding patients’ gender or weight. Patients’ ages ranged
from 4 to 16 years and their mean age was (11±0.67 years).
Table 3 summarizes the demographic data.
All patients (n=140) included in this study underwent
CT scan; it was the initial imaging in 102 patients and
subsequently US imaging was performed for the remaining
38 patients. Forty-four patients had radiological findings
coping with acute appendicitis in CT examination, which
was correlated with the histopathological findings: 16 showed
dense fecolith; perforation was noted in 7 (3 of them were
associated with fecolith as shown in Figure 1); and 1 was
associated with an acute abscess. The most common loca-
tion of the appendix with inflammation was pelvic region
(19 cases, 42%) followed by retrocecal (16 cases, 36%).
Table 4 summarizes radiological signs of patients.
Only 1 patient was misdiagnosed by CT as having a
normal appendix with a probably complicated right ovarian
cyst. As this patient had persistent pain and tenderness in
right iliac fossa, she was referred to laparoscopic surgery
that revealed mild inflammation in her appendix with right
corpus luteum cyst.
CT examination showed a sensitivity of 97.8% (95%
confidence interval [CI] =88.2%–99.9%), specificity of
100% (95% CI =96.2%–100%), PPV of 100%, NPV of 98.7%
(95% CI =93.2%–99.9%), and an accuracy of 99.3%.
Table 3 Demographic and clinical characteristics of all study
patients (n=140)a
Appendicitis
(n=45)
No appendicitis
(n=95)
P-value
age (years) 13.1±4 13.2±3.9 P=0.885b
t-value =−0.144
gender
Male
Female
27 (60%)
18 (40%)
50 (54%)
45 (46%)
χ2=0.6699
P=0.413c
Weight (kg) 45.65±18.2 47.2±19 t-value =0.586
P=0.559b
symptoms
duration (days)
1.85±0.56 2.0±1.11 P=0.210b
t-value =1.258
Pediatric
appendicitis score
5.34±1.15 2.48±1.11 t-value =−17.947
P,0.001b
Notes: aContinuous variables are presented as mean ± standard deviation; categorical
variables as numbers with percentages; bUnpaired t-test, cchi-square test.
Figure 1 Preoperative postcontrast abdominal–pelvic CT scan of a child aged 14 years, who presented with abdominal pain and vomiting (Pas score =5).
Notes: (A and B) Coronal reformatted images showed distended appendix with thick edematous walls, diameter 15 mm (long black arrow in A), which contains fecolith
(short double black arrows in A). a tiny focus of air near its tip denoting contained perforation (white arrow in B); multiple associated regional and mesenteric lymph
nodes (black arrows in B). (C) axial image showed distended appendix with thick edematous walls surrounded by peri-appendiceal fat stranding, and mild peri-appendiceal
fluid (black arrow in C).
Abbreviations: Pas, pediatric appendicitis score; CT, computed tomography.
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Reliability of Pas, Us, and CT in the diagnosis of pediatric appendicitis
The mean dose-length product was 150 mGy/cm (ranging
from 115 to 200 mGy/cm) and mean effective dose of radia-
tion was 3.1 mSv (ranging from 2.2 to 3.4 mSv).
The abdominal US examination was the initial imaging
in 38 patients; it gave true positive results in 10 cases
(26.3%), true negative in 17 cases (44.7%), false negative
(missed appendicitis) in 8 cases (21%), and false positive
(negative appendectomy) in 3 cases (7.9%). It showed a
sensitivity of 55.6% (95% CI =30.8%–78.5%), specificity
of 85% (95% CI =62.1%–96.8%), PPV of 76.9% (95%
CI =52%–91%), NPV of 68% (95% CI =55.1%–78.6%),
and an accuracy of 71%. In 2 patients (who were negative
for appendicitis), abdominal US examination revealed right
ovarian cysts 3 cm and 3.5 cm in diameter, respectively.
Following Poortman’s model10 (which consisted of
combination of US as the primary examination followed by
CT in nondiagnostic US examination) yielded a sensitivity
of 100% (95% CI =81.5%–100%), specificity of 85% (95%
CI =62.1%–94.5%), PPV of 85.7% (95% CI =67.9%–78.6%),
an accuracy of 92%, negative appendectomy rate of 7.9%,
and no missed positive appendicitis cases. It alone would
have avoided the use of CT in 13/38 cases.
There was a significant difference between the PAS
in positive and negative appendicitis groups (P,0.001).
In this study, PAS score $5 was found to be the best cutoff
point compatible with acute appendicitis; it resulted in a
sensitivity of 95% (95% CI =29%–98%), specificity of 84%
(95% CI =76%–90%), PPV of 82% (95% CI =73%–89%),
NPV of 82% (95% CI =73%–89%), and accuracy of 89%
(as shown in Figure 2). Further analysis of PAS showed
that it is more useful as an exclusive tool; PAS $2 showed
the highest sensitivity of 97.8% (95% CI =88.2%–99.9%)
with only a single false negative case (missed appendicitis),
whereas using higher cutoff value (PAS $7) showed the
highest specificity 97.9% (95% CI =2.6%–99.7%) with only
2 cases of negative appendectomy (Table 5).
On comparing low-dose CT, US, Poortman’s model, and
PAS (using a cutoff value $5), low-dose CT showed the high-
est accuracy, whereas US showed the lowest (Table 6).
On one side, there was a significant difference in accuracy
between low-dose CT scans and PAS (P,0.001), and on the
other side, there was a significant difference between Poort-
man’s model and US (P,0.02).
Finally, we propose a diagnostic scheme that depends on
the clinical score (PAS) as an initial diagnostic tool followed
by US examination (if PAS is in the range of 3–6), preserving
low-dose CT as the last step for cases with inconclusive US
findings (as shown in Figure 3). Following this scheme would
have eliminated the use of CT for at least 47/140 (33.6%)
patients who had PAS #2 or $7. Unfortunately, not all
patients included in this study had US examination; however,
following this scheme for the remaining 38 patients who had
initial US examination would have avoided the use of CT in
7 cases (PAS 3–6 and positive US findings).
Discussion
Owing to its high diagnostic accuracy, CT is utilized widely
in the management of appendicitis, but this trend is accom-
panied by an increased radiation exposure and long-term
Table 4 Computed tomography (CT) findings in positive
appendicitis cases
CT findings Patients (n)
edematous wall 44
Perforation 8
Fecolith 16
Fecolith associated with perforation 3
enlarged regional and mesenteric lymph nodes 24
abscess 1
according to the appendix location
Pelvic
Retrocecal
subhepatic
anterior
19
16
2
7
Figure 2 Receiver operating characteristic curve for the performance of pediatric
appendicitis score.
Note: Area under curve (95% confidence interval) =0.951 (0.923–0.979).
Table 5 Sensitivity and specificity of PAS values (using 3 different
cutoff points) in all subjects (n=140), according to final diagnosis
PAS cutoff Sensitivity Specificity Accuracy
Pas $2 97.8%
(95% Ci: 88.2–99.9)
26.3%
(95% Ci: 17.8–36.4)
49.3%
Pas $5 95%
(95% Ci: 29–98)
84%
(95% Ci: 76–90)
89%
Pas $7 42.2%
(95% Ci: 27.7–57.9)
97.9%
(95% Ci: 92.6–99.7)
73%
Abbreviations: PAS, pediatric appendicitis score; CI, confidence interval.
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cancer risks.4 Two main pathways have been suggested
to decrease these hazards and maintain high diagnostic
accuracy; first to decrease the radiation dose by implement-
ing a low-dose protocol in pediatric CT (image gently), and
second, to decrease the utilization of CT by using a clinical
score and US examination either alone or prior to CT, which
can be performed in case of doubt (this decision should be
made wisely).
In the current study, a low-dose protocol was used for all
patients with a mean radiation dose of 3.1 mSv. Although
the low-dose technique resulted in reduced quality of images
it did not affect the diagnostic accuracy. CT examination
showed a sensitivity of 97.8%, specificity of 100%, and an
accuracy of 99.3%. These results agree with other studies11–14
in which the authors have reported no significant difference
in sensitivity, specificity, negative appendectomy, or missed
appendicitis rate between low-dose protocol and regular
CT scan.
In the current study, graded compression US was per-
formed for a relatively small group of patients (38 cases). It
had less sensitivity (55.6%), specificity (85%), and accuracy
(71%) compared to CT, which could be attributed to 2 main
reasons. First, all sonographic examinations were performed
in our institution by a general radiologist, not by a pediatric
sonologist; second, owing to the high percentage of a retro-
cecal position of the appendix (36%) which hindered its
detection by the US.
Poortman et al10 suggested a diagnostic model for appen-
dicitis that included graded compression US as the initial
imaging modality followed by CT only in nondiagnostic US
examination. Applying this model to a relatively small group
of patients in the current study, it was found that primary US
examination dramatically improved the sensitivity (100%),
specificity (85%), and accuracy (92%), and yielded a nega-
tive appendectomy rate of 8% and no missed appendicitis.
These results are similar to those in the studies of Poortman
et al10 (sensitivity of 100%, specificity of 86%, and negative
appendectomy 8%), Ramarajan et al15 (sensitivity of 99%,
specificity of 91%, and negative appendectomy 7%), and
Thirumoorthi et al16 (sensitivity of 94.2%, specificity of
97.5%, negative appendectomy 1.8%, and missed appen-
dicitis 0%).
One study reported an increasing trend of using US as
the first imaging tool (about 69% instead of 32.6%) during
the period from 2008 through 2013, whereas the use of CT
was decreased.18 In the current study, US examination was
the initial imaging modality in 27% of the cases suspected
to have appendicitis. In contradiction to other studies which
reported utilization of preoperative CT in about 40% of the
cases,17–19 in our study, all patients undergoing appendectomy
had received a preoperative CT, even if the patient had a US
diagnosis of appendicitis. The reasons behind this could be
that surgeons in our region have less trust in US results as
compared to CT, which has higher sensitivity, specificity,
and is indeed less operator-dependent. Although CT is more
Table 6 Comparison of performance between CT, Us, Poortman’s model, and Pas
PAS $5
(n=140)
CT
(n=140)
US
(n=38)
Poortman’s model
(n=38)
sensitivity 95% 97.8% 55.6% 100%
Specificity 84% 100% 85% 85%
Positive predictive value 82% 100% 76.9% 85.7%
negative predictive value 82% 98.7% 68% 100%
accuracy 89% 99.3% 71% 92%
negative appendectomy
(false positive)
4 (2.8%) 0 3 (7.9%) 3 (7.9%)
Missed appendicitis
(false negative)
9 (6.4%) 1 (0.7%) 8 (21%) 0
Abbreviations: CT, computed tomography; Pas, pediatric appendicitis score; Us, ultrasound.
Figure 3 a suggested scheme for the diagnosis of appendicitis using Pas, Us, and
low-dose CT scan.
Abbreviations: Pas, pediatric appendicitis score; Us, ultrasound; CT, computed
tomography; −ve, negative; +ve, positive.
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853
Reliability of Pas, Us, and CT in the diagnosis of pediatric appendicitis
expensive than US, it is still less expensive than the cost of
negative appendectomy or managing complications such as
a perforated appendix. Furthermore, physicians find difficulty
in convincing some parents of the diagnosis of acute appen-
dicitis based only on clinical and US findings; they believe
that CT scan can be less harmful than doing unnecessary
appendectomy with possible surgical complications.
The main drawback of US is that it is highly operator-
dependent and its accuracy is affected dramatically by the
examiner’s own experience. That is why CT scan utilization
is higher in general hospitals (including our hospital) when
compared to specialized pediatric hospitals. This is in agree-
ment with Kotagal et al17 who noted 8 times higher use of
CT in nonpediatric hospitals.
Appendicitis scoring systems have been developed as a
diagnostic tool to improve the decision-making process in
patients with suspected acute appendicitis.20 In the current
study, PAS score $5 was found to be the best cutoff point
compatible with acute appendicitis, with a sensitivity of 95%,
specificity of 84%, and an accuracy of 89%. However, there
was still a significant difference in accuracy between low-
dose CT and PAS. In this study, it has been found that rely-
ing on a single PAS cutoff value would result in a negative
appendectomy in 4 cases (2.8%) and missed appendicitis in
9 cases (6.4%). Other studies suggested a modified pathway
utilizing both PAS and imaging; Lourenco et al21 suggested
that patients with a PAS of 1 to 3 could be discharged without
further imaging examination, patients who had a PAS of 4
to 6 would require further imaging examination, and those
who had a PAS of 7 to 10 required surgical consultation
without imaging examination. Similarly, Goldman et al22
reported that a score of 7 or greater is valid for the diagnosis
of appendicitis and a score of 2 or under is valid for the exclu-
sion of appendicitis; and Zúñiga et al23 found that at PAS
of #3 no patients were diagnosed with acute appendicitis,
and if all patients with PAS of 8 or higher were operated on,
there was a 5% rate of negative appendectomy.
Similarly, in the current study, we found that using
PAS #2 to exclude the diagnosis of appendicitis would have
led to missing only 1 case (0.7%), whereas using PAS $7 as
an indication for surgery would have led to negative appen-
dectomy in 2 cases (1.4%); the rest of the patients having
PAS between 3 and 6 were in need of further imaging studies.
Accordingly, we have proposed a diagnostic scheme for acute
appendicitis (Figure 3) that combines three diagnostic tools
(PAS, US, and low-dose CT). Obviously, following this
pathway will result in fewer cases of missed appendicitis or
negative appendectomy as compared to using US or PAS
alone, whilst also lowering CT utilization. We found that fol-
lowing this scheme would have eliminated the use of CT for
at least 33.6% (47/140) of the patients who had PAS #2 or
$7, and in 7 patients who had initial US examination before
CT. In contrast, these results disagree with Srinivasan et al24
who found little benefit in performing CT for patients with
PAS ,6 and negative US findings. Again, this could be
attributed to the fact that our study was conducted in a general
hospital and not in a tertiary pediatric center, and because
US was performed by general radiologists and not pediatric
sonologists. However, Rezak et al25 reported about 27% theo-
retical decrease in CT utilization in children with suspected
appendicitis with modified Alvarado score (5–7).
In the current study, PAS that equals 5 or more was found
to be the best cutoff value for diagnosis of appendicitis;
however, this value is less than that found by several other
studies including Samuel9 who created this score system
back in 2002. This difference could be attributed to inher-
ited difference between prospective and retrospective study.
In the current study, examination of patients was performed
by pediatricians and not by pediatric surgeons who could
have underestimated the clinical signs. Other factors related
to local population habits, such as giving children several
analgesics and antipyretics without medical prescription,
which could mask clinical signs. Another factor is difficulty
in communication, as our hospital serves patients coming
from multiple nationalities with different languages. To our
knowledge, this is the first study to assess the validity of PAS
as a diagnostic tool for pediatric appendicitis in our region;
further large prospective multicenter study is recommended
to clarify more its diagnostic value.
There are some limitations in this study. First, the overall
low number of cases included and the even fewer cases that
had US examinations. As the number of patients who had
US examination was less than those who had CT examina-
tion, we were not able to apply Poortman’s model and our
final diagnostic scheme for all cases. Second, all cases had
low-dose CT examination performed, and we were not able
to compare between low and ordinary dose CT in order to
get true measurements of degree of dose reduction. Finally,
the retrospective nature of this study hindered our ability to
assess the feasibility of the suggested diagnostic scheme on
daily work instead of assumption.
Conclusion
Although CT remains the most accurate and less operator-
dependent diagnostic tool for pediatric appendicitis, radiation
hazards could be minimized using PAS as an excluding tool
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and US as primary imaging modality, followed by low-dose
CT for inconclusive cases only.
Disclosure
The authors report no conflicts of interest in this work.
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