Journal App 2
Journal App 2
Journal App 2
5A, 23-28
Available online at http://pubs.sciepub.com/ajphr/3/5A/6
© Science and Education Publishing
DOI:10.12691/ajphr-3-5A-6
Abstract Acute appendicitis is commonest cause of acute abdomen necessitating emergency abdominal surgery.
Although diagnosis is still largely considered to be a clinical one, ultrasound is established as easily available, less
time consuming and very accurate at timely diagnosis of acute appendicitis largely reducing complications as well as
negative laparotomies. Due to development of high frequency transducers and better resolution, ultrasound is highly
specific and sensitive in diagnosis of acute appendicitis. This study was done to establish the diagnostic role of
ultrasound in acute appendicitis in western region of Nepal. Total number of 125 patients were included in the study
from May 2013 to May 2015. Findings on ultrasound were finally compared with histopathological report of
appendices removed on surgery. Those cases with alternate diagnosis were followed up and proved with other
means of investigation. The sensitivity, specificity, positive predictive value, negative predictive value and overall
accuracy of ultrasound in diagnosis of acute appendicitis in our study were found to be 95.12 %, 88.88 %, 97.5% ,
80% and 82 % respectively.
Keywords: appendicitis, ultrasonography, specificity, Nepal
Cite This Article: Subash K C, Abhijit De, Mahesh Pathak, and Brijesh Sathian, “Diagnostic Role of
Ultrasonography in Acute Appendicitis: A Study at a Tertiary Care Hospital.” American Journal of Public Health
Research, vol. 3, no. 5A (2015): 23-28. doi: 10.12691/ajphr-3-5A-6.
with availability of high frequency transducers, it is easier 3. Cases of acute appendicitis not willing for further
to diagnose appendicular pathologies owing to its better management were excluded from the study.
resolution. Graded compression sonography is particularly 4. Patients not giving consent
useful in cases of suspected uncomplicated acute 5. Pregnant patients
appendicitis. Obvious benefits of ultrasound are
i No ionizing radiation, non-invasive 3.4. Sonological Equipment Used
ii Minimal discomfort to the patient
iii Easy availability, portability, and repeatability ACUSON X300 and LOGIQ P3 with multi-frequency
iv No specific patient preparation required. linear array transducer (7.5MHz-10.0MHz) and curvilinear
In many centers, sonography has become the procedure transducer (3.5MHz-7.0MHz) was used for our study.
of choice for the initial evaluation of acute appendicitis
with equivocal clinical features, particularly in pediatric 3.5. Method of Examination
and women of childbearing age group. All US studies were performed with the 7.5-10.0MHZ
Very few studies have been conducted in our part of the linear array transducer. In women a US study of abdomen
country and sufficient data was not available regarding the and pelvis was acquired with 3.5MHz-7.0MHz curvilinear
role of sonography in the evaluation of clinically transducer with the patient’s bladder partially filled. By
suspected cases of appendicitis. Hence, this study was using a linear array transducer the sonographic plane was
conducted to establish the role of sonography either in perpendicular to the table, the special flat T-shape enabled
diagnosis or in ruling out appendicitis as the cause of the examiner to exert gentle compression with the
acute abdomen, thus enabling in avoiding unnecessary transducer using both hands in the same way as when
negative laparotomies. palpating the abdomen.
The method of examination in this study was as per the
graded compression technique described by Puylaert [7].
2. Aims & objectives
The specific aim of our study was to determine the
3.6. Ethical Clearance
following with USG in suspected acute appendicitis: Prior to the study, ethical approval from the
• specificity institutional ethical committee was taken. Informed
• sensitivity consent was taken from all the patients involved in the
• positive predictive value study and confidentiality was maintained.
• negative predictive value
• accuracy. 3.7. Sample size Calculation
In a pilot study done prior to this study, showed
sensitivity of USG in diagnosis of acute appendicitis as
3. Methodology 95%, with 95% CI and 5% allowable error. Sample size
required was 80 [8].
A structured pre-prepared case proforma was used to
enter the complete history, investigations-hematological
and ultrasound, per-operative findings and histopathological 4. Results
report.
Out of 125 patients included in our study, 105 patients
3.1. Criteria for evaluation and definitions underwent surgery and ultrasound findings were
Visualization of inflamed appendix or identification of correlated with histopathology report as shown in Table 1.
periappendiceal abscess with ultrasound was considered
Table 1. Results of Sonographic Studies in Diagnosis of Acute
positive for the diagnosis of appendicitis. Visualization of Appendicitis
appendix less than 6mm or non-visualization was recorded Total No Proven On Sonography
as a negative result. of Cases Histopathol True True False False
If the inflamed appendix could be identified, the largest ogy Positive Negative Positive Negative
outer diameter was measured using electronic calipers. A 125 105 98 20 2 5
histopathological examination of surgically removed Appendix was visualized in total 100 cases with
appendices, formed the basis for definitive judgement. associated other features of inflammation as described in
Diagnosis in patients not undergoing surgery were Table 2.
verified by evaluating all examinations, including follow
up observations. Table 2. USG Findings in Histopathologically Proven Appendicitis
USG Findings No. of Cases Percentage
3.2. Selection Inclusion Criteria Visualization of Appendix 100 95.23
Target Sign on Transverse Scan 100 95.23
All Patients irrespective of age and sex clinically Sonographic Mcburney’s Tenderness
105 100
suspected to be having acute appendicitis. (Probe Tenderness)
Appendicolith 8 7.6
3.3. Exclusion Criteria Free Fluid in Right Iliac Fossa 70 66.66
Echogenic Surrounding Mesentery 85 80.95
1. Moribund patients not fit for surgery
Loss of Submucosal Integrity 30 28.57
2. Complications of appendicitis like abscess, lump etc.
American Journal of Public Health Research 25
Out of 100 cases reported as appendicitis on ultrasound, Table 4. Diagnostic Role of USG
98 were found to be appendicitis on histopathology where Evaluation of USG Values (%)
as 2 of them were negative for appendicitis as shown in Sensitivity 95.14
Table 3. Specificity 90.90
Positive Predictive Value 98
Table 3. Correlation of Ultrasound with Histopathological
Examination Report Negative Predictive Value 80
Total Number of Cases 125 Diagnostic Accuracy 94.4
USG positive 100
USG negative 25
HPE positive 98 5. Discussions
HPE negative 2
USG negative cases operated 15 Our study was a prospective study of 125 patients
HPE positive 5 clinically suspected for acute appendicitis. After a detailed
HPE negative 10 history and clinical examination, the patients were subjected
Results to ultrasound examination of the right iliac fossa using
True positive 98 graded compression technique as explained by Puylaert
True negative 20 using high resolution, high frequency probes (linear array
False positive 2 7.5-10MHz and curvilinear array 3.5-7.0MHz).
False negative 5 Age prevalence showed less than 4.8 % of patients in
Diagnostic role of ultrasound was evaluated by the age group of 1-10 years and 11.9 % of patients above
calculating sensitivity, specificity, positive predictive the age group of 50 years were affected. Males were more
value, negative predictive value and overall diagnostic commonly affected than females, with a male: female
accuracy using standard formulae and values obtained are ratio of 1.62:1. These results were comparable to the study
shown in Table 4. done by Lewis et al [9] who observed that less than 10%
of patients were affected in the age group of 1-10 years
and less than 10% of patients were affected in the age
group of 50 years and above with male: female ratio of 2:1.
Our study showed that highest number of acute
appendicitis occurred in the age group of 11-20 years
followed by age group of 21-30 years which is consistent
with the findings shown by Addis et al [2] that it is most
common in 10 to 19 year old age group.
5.1. Symptoms
Patients presented with various symptoms among which
73.8 % patients had periumbilical pain radiating to right
iliac fossa or pain starting directly in right iliac fossa. No
significant difference in duration of pain existed between
acute appendicitis and other pathological conditions like
renal/ureteric colic. Lewis et al [9] noted pain abdomen in
99% of patients, which was localized to the right lower
quadrant in 75% of patients and 10% to the periumbilical
area. Anorexia was seen in 52.38 % cases. Nausea was
seen in 69.04% cases where as vomiting was seen in
Figure 1. USG showing target sign of inflamed appendix with wall to 35.71 % of patients. Fever was seen in 38.9% of patients.
wall diameter of 8.1mm
Our findings are similar to study done by Tauro LF et al
[10] in which 37 % patients of acute appendicitis had
fever No significant difference in the presentation of
illness was seen in other causes of right lower quadrant
pain in our study compared to acute appendicitis. This is
in conformity with the study done by Lewis et al [9].
5.2. Signs
In the current study, tenderness in right iliac fossa was
seen in 100 % cases whereas rebound tenderness at
McBurney’s point was noted in 92.85% of patients which
is similar to the finding noted by Tauro LF et al [10]
which showed 100% patients having right iliac fossa
tenderness and 65 % patients having rebound tenderness at
McBurney’s point. Sohail et al. [11] emphasized the same
finding that scanning the point that the patient says hurts
Figure 2. USG showing irregular wall thickening and mucosal
irregularity in inflamed appendix. Diameter is approx. 8.4 mm the most increases the detection rate of appendicitis.
26 American Journal of Public Health Research
5.3. Laboratory Investigations [19] reported that with the use of additional operator
dependant techniques, detection rates of normal and
Total white cell count was raised significantly in abnormal appendices have greatly increased. In our study
88.09% of our patients. Significant neutrophilia was we identified 3 normal appendices accounting for 2.4 % of
present in 71.42% of our patients These results were the total number of cases. This finding is similar to study
comparable to the study done by Lewis et al. [9] The done by Jeffrey et al [17]. The normal appendix was
results are also in accordance to study done by Kessler et compressible, less than 6mm in diameter and appeared
al. [12] in which white blood cell count above 10,000/L ovoid in cross-section. In this case we confidently
had a sensitivity of 77% and specificity of 63%. In study excluded the diagnosis of acute appendicitis. This finding
done by Taura LF et al.[10] Leucocytosis was present in was similar to that of Thomas Rettenbacher et al [20]. In
75% of the cases and Neutrophilia in 86% of the cases. A the remaining 5 cases ultrasound was unable to detect
study of 225 patients by Doraiswamy [13] showed appendix, either normal or abnormal. This was due to
leucocytosis in 42% and neutrophilia in 96% of the cases. presence of guarding and rigidity, which hinders
compression, non-visualization of normal appendix per se,
5.4. Ultrasonography in the Diagnosis of presence of localized ileus and obesity. In all cases of
Acute Appendicitis acute appendicitis, probe tenderness was present at the
Puylaert [7] was the pioneer of graded compression McBurney’s point. In 95 cases (90.47 %) of the total
sonography in the diagnosis of acute appendicitis. number of cases where we could see an inflamed appendix,
High-resolution real time sonography is non-invasive it was non-compressible and spherical in shape in all the
diagnostic modality which is readily available and enables cases. It is in accordance with Grebeldinger [21] who has
direct visualization of an inflamed appendix or concluded that the most relevant criteria for USG
periappendiceal abscess. Extended sonography is also of evaluation was non-compressibility (97.67%). The outer
value in patients without evidence of acute appendicitis. It diameter of the appendix was greater than 6mm in all the
can provide echo morphologic findings that may suggest 95 cases. It is similar to the criteria laid down by Jeffrey et
an alternate diagnosis such as mesenteric adenitis, al [17] and reinforced by Thomas Rettenbacher et al [20].
terminal ileitis, gynecologic disorders and urologic The overall accuracy of sonography in the diagnosis of
diseases as quoted by Geansler et al [14], Ooms et al [15] acute appendicitis in our study was 94 %. In this study,
and Abu-youseff [6]. sensitivity, specificity, positive predictive value and
In our study USG could visualize 98 appendices out of negative predictive value of ultrasound scanning with
125 cases who had clinical presentation of acute appendicitis, reference to histopathological confirmation was 95.12 %,
from which true positive cases of appendicitis were found 88.88 %, 97.5% and 80% respectively which showed that
after surgery and HPE. John et al [16] could diagnose 70 USG has a high specificity and sensitivity in diagnosing
out of 140 cases as acute appendicitis by USG. appendicitis. The overall specificity and sensitivity rates
Puylaert [7] et al did not demonstrate normal appendix were comparable to the studies and results of Skanne et al
by sonography. However recent reports where high [22], Hahn et al [23] , Tarzan Z et al [24] and Puylaert et
frequency transducers were used did show normal al [25] whose specificity values varied from 90- 100% and
appendix in a small percentage of cases (5 out of 250 sensitivity ranges varied from 70-95%.
cases) as reported by Jeffrey et al [17]. Similar findings The table below (Table 5) summarizes the results of the
were shown by Rioux et al [18]. More recently Lee et al present study compared with the results of similar studies
done in different parts of the world.
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