Accuracy of Ultrasonography in the Diagnosis of Peritonitis Compared With the Clinical Impression of the Surgeon

ORIGINAL ARTICLE
Accuracy of Ultrasonography in the Diagnosis
of Peritonitis Compared With the Clinical
Impression of the Surgeon
Shyr-Chyr Chen, MD; Fang-Yue Lin, MD, PhD; Yeu-Sheng Hsieh, PhD; Wei-Jao Chen, MD, PhD
Hypothesis: Peritonitis is a well-known indication for
Results: Ultrasonography and clinical impression
surgery, but its preoperative cause usually is not estab-
accurately diagnosed the peritonitis in 85 (83.3%) and
lished. We hypothesize that abdominal ultrasonogra-
52 (51.0%) of the patients, respectively. The difference
phy is superior to the clinical impression of the surgeon
between ultrasonography and clinical impression in the
in detecting the cause of peritonitis.
diagnosis of peritonitis was significant (P .001).
Among 45 patients without a preoperative clinical diag-
Design: A prospective case series.
nosis, a diagnosis was made by ultrasonography for 32
(71%) of them. There were a total of 98 patients with
Setting: A major university hospital in Taiwan, Repub-
positive ultrasonographic findings, and 4 patients had
lic of China.
normal screening results. Of the 98 patients with posi-
tive ultrasonographic findings undergoing surgery, all
Patients and Methods: One hundred two patients
had abdominal pathological characteristics. The 4
with a diagnosis of peritonitis admitted to the Depart-
patients with normal screening results received nonop-
ment of Emergency Medicine, National Taiwan Univer-
erative treatment.
sity Hospital, Taipei, were included in this study. All
102 patients underwent an abdominal ultrasonographic
Conclusions: Ultrasonography is a more sensitive tech-
examination; and the ultrasonographic findings of these
nique than clinical judgment in diagnosing peritonitis.
patients were classified into 2 categories: positive find-
Ultrasonography may be a useful diagnosing modality
ings and normal screening results. The accuracy of
in patients with peritonitis in whom the clinical cause is
clinical impression in detecting the cause of peritonitis
unclear.
was compared with the accuracy of abdominal ultrason-
ography.
Arch Surg. 2000;135:170-173
ACONCERNINGfractionof morbidityandprolongedhospitaliza-
patients who present with
tion.1-5 To reduce the rate of unneces-
acute abdominal pain have
sary laparotomy, additional sensitive
peritonitis. Peritonitis re-
and specific examinations are needed to
fers to any inflammation of
the peritoneal layers, and it is an emer-
See Invited Critique
gency condition that frequently requires
surgery. Not every underlying cause of
at end of article
peritonitis is diagnosed before surgery, and
laparotomy has, therefore, traditionally
screen patients for operative indications
been advised to treat the patient’s disease
before surgery. Plain radiography, lapa-
and to determine the nature of the ab-
rotomy, computed tomography, and
dominal pathological features. However,
ultrasonography have been used to aid
From the Departments of
some medical conditions may mimic acute
in the diagnosis of peritonitis. To our
Emergency Medicine
peritonitis, which do not require surgical
knowledge, the role of the abdominal
(Drs S.-C. Chen and Lin) and
intervention. Should surgeons operate im-
ultrasonographic examination in patients
Surgery (Dr W.-J. Chen),
mediately and face the possibility of find-
with peritonitis has not been well re-
National Taiwan University
ing a nonsurgical condition at lapa-
ported. This prospective study compared
Hospital, and the Department of
rotomy, or should they observe and risk
the diagnostic accuracy of abdominal
Agricultural Extension,
National Taiwan University
missing the optimal time for surgery?
ultrasonography with the clinical im-
(Dr Hsieh), Taipei, Taiwan,
Unnecessary laparotomy has been
pression of the surgeon in diagnosing
Republic of China.
reported to be associated with increased
peritonitis.
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PATIENTS AND METHODS
first screened to check the antrum, the first portion of the
duodenum, and the pancreas; then screening was shifted to
the right hypochondriac region and subcostal area to check
All patients with peritonitis admitted to the Department of
the liver, the gallbladder, and the right pleural space. The
Emergency Medicine, National Taiwan University Hospi-
presence of free air was checked in both regions. Follow-
tal, Taipei, Taiwan, Republic of China, from August 1996
ing this, the right paracolic gutter was examined to check
through March 1999, were included in this prospective
the ascending colon, the terminal ileum, and the appen-
study. Those patients with abdominal injury were ex-
dix. Then the rectouterine pouch and the left subcostal
cluded. The study included 102 patients (68 male and 34
area were investigated to check the pelvic condition, the
female patients). The age of these patients ranged from 13
spleen, and the left pleural space. The left paracolic gutter
to 83 years (mean, 47 years).
was screened next to check the descending colon. Finally,
When patients arrived at the hospital, they were ex-
the central abdomen was examined to check the small
amined by a member of the surgical house staff. After ob-
intestine.
taining a detailed medical history and performing a physi-
The results of the ultrasonographic examination were
cal examination, venous blood from each patient was
categorized as either a positive ultrasonographic finding or
sampled and a plain abdominal radiograph or a chest ra-
a normal screening result. A positive ultrasonographic find-
diograph was obtained. The clinical diagnosis of peritoni-
ing was defined as any additional or abnormal ultrasono-
tis is defined as a patient having diffuse abdominal tender-
graphic changes in the abdominal cavity. The ultrasono-
ness, rebounding pain, and leukocytosis. If peritonitis was
graphic diagnosis was also recorded. The decision to operate
diagnosed, the presumed cause was recorded, which was
was based on the presence of or highly suspected surgical
blinded from the ultrasonographer, and the patient then
disease found by ultrasonography. Those with normal
underwent an abdominal ultrasonographic examination per-
screening results were hospitalized for close observation
formed by a staff surgeon. This surgeon had 6 years of ex-
and continued investigation. Additional tests, including pan-
perience in performing abdominal ultrasonographic ex-
endoscopy or computed tomography, were performed to
aminations. Ultrasonography was performed with a
search for an underlying cause of peritonitis in those pa-
handheld 3.75-MHz curved-array transducer (model SSA-
tients with normal ultrasonographic screening results. The
340A; Toshiba, Tochigi-Ken, Japan) over the whole abdo-
relation between operative findings and ultrasonographic
men, with screening of the pleural space, hepatorenal re-
findings was examined in the assessment of the diagnostic
cess, paracolic gutter, rectouterine pouch, liver, biliary tract,
accuracy of ultrasonography. The statistical difference in
gallbladder, spleen, pancreas, small intestine, colon, and
this study was determined by the 2 test. P .05 was con-
intra-abdominal fluid collections. The epigastric area was
sidered significant.
RESULTS
found to have a peptic ulcer without perforation or ob-
struction. They received a hydrogen blocker and ant-
The findings of the abdominal ultrasonographic exami-
acid treatment and were followed up at the outpatient
nation are shown in Table 1. The ultrasonographic di-
clinic. One of these patients underwent abdominal com-
agnoses of 102 patients with peritonitis are shown in
puted tomography, which showed no abnormalities. She
Figure 1. There were 98 patients with positive ultraso-
received conservative treatment and was discharged from
nographic findings and 4 patients with normal screen-
the hospital 2 days later, after her abdominal pain ceased.
ing results. The cause of the peritonitis in 85 patients was
The symptoms of all 4 patients with normal screening
accurately diagnosed by ultrasonography. Incorrect ul-
results resolved without surgery, and recovery was veri-
trasonographic diagnoses were found in 5 patients, in-
fied at the outpatient clinic 2 weeks later.
cluding 2 with pneumoperitoneum, 2 with internal bleed-
Among the 57 patients with a preoperative clini-
ing, and 1 with perforated appendicitis. The intraoperative
cal impression (Figure 2), 5 (9%) of these diagnoses
findings in patients who underwent laparotomy were as
were changed based on ultrasonographic findings,
follows:
including 3 cases of pneumoperitoneum and 2 cases of
perforated appendicitis. Ultrasonographic diagnoses
Type of Disease
No. of Patients
were also made in 32 of the remaining 45 patients
Perforated duodenal ulcer
32
without a previous clinical impression (Table 2). In
Perforated gastric ulcer
25
the 102 patients, an accurate diagnosis was made
Perforated appendicitis
13
Colonic perforation
9
based entirely on the clinical impression in 52 patients
Intestinal perforation
3
(51.0%) and based entirely on ultrasonographic
Diverticulitis rupture
5
examination results in 85 patients (83.3%) (P .001).
Intra-abdominal abscess
5
These results clearly show that ultrasonography is a
Acute cholecystitis
3
more sensitive modality than clinical judgment in
Ischemic bowel
2
detecting the cause of peritonitis.
Intestinal leiomyosarcoma
1
The most common ultrasonographic findings were
Total
98
ascites, dilated small-bowel loop with wall thickness,
The 4 patients with normal screening results re-
pneumoperitoneum, thickness of the antrum or duode-
ceived conservative treatment, and 3 of them under-
nal wall, perforated appendicitis with perifocal exudate
went an additional panendoscopic examination and were
accumulation, and abscess formation.
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102 Patients
Table 1. Findings of an Abdominal Ultrasonographic
Examination in 102 Patients
102 (100%)
0
With Positive
With Negative
No. of
Clinical Findings
Clinical Findings
Ultrasonographic Findings
Patients
Abnormal
98
57 (55.9%)
45 (41.1%)
Ascites
77
With a
Without a
Pneumoperitoneum
62
Clinical Diagnosis
Clinical Diagnosis
Small-bowel edema
54
Thickness of the antrum or duodenal wall
18
52 (51.0%)
5 (4.9%)
With a
With an
Perforated appendicitis
12
Correct Diagnosis
Incorrect Diagnosis
Diverticulitis rupture
4
Intra-abdominal abscess
4
Figure 2. Clinical impression of 102 patients with peritonitis.
Acute cholecystitis
3
Internal bleeding
2
Pelvic mass
1
Normal
4
Table 2. A Comparison of Diagnosis Based Entirely
on Ultrasonographic or Clinical Findings in 102 Patients*
Disease
Ultrasonographic
Clinical
(No. of Patients)
Diagnosis
Diagnosis
102 Patients
Hollow organ perforation (69)
62†
49‡
98 (96.1%)
4 (3.9%)
Perforated appendicitis (13)
12§
8†
With Positive
With Negative
Intra-abdominal abscess (5)
4
0
Ultrasonographic Findings
Ultrasonographic Findings
Diverticulitis rupture (5)
4§
0
Acute cholecystitis (3)
3
0
90 (88.2%)
8 (7.8%)
Peptic ulcer (3)
0
0
With an
Without an
Ischemic bowel (2)
2
0
Ultrasonographic Diagnosis
Ultrasonographic Diagnosis
Leiomyosarcoma rupture (1)
1
0
Internal bleeding (0)
2†
0
85 (83.3%)
5 (4.9%)
Unknown (1)
12
45
With a
With an
Total (102)
102
102
Correct Diagnosis
Incorrect Diagnosis
*Data are given as number of patients.
Figure 1. Ultrasonographic diagnoses of 102 patients with peritonitis.
†Included 2 incorrect diagnoses.
‡Included 3 incorrect diagnoses.
§Included 1 incorrect diagnosis.
COMMENT
Pelvic mass.
Peritonitis continues to be one of the major abdominal
emergencies confronting surgeons. The prognosis of peri-
sive, cost-effective, easily accessible, and accurate in the
tonitis is poor, especially when multiple organ failure or
diagnosis of peritonitis.
sepsis develops.6-9 The wide range of causes and varied
Commonly performed additional imaging studies in-
patient presentations pose a formidable diagnostic and
clude plain radiography, laparoscopy, ultrasonography, and
therapeutic challenge to the surgeon. Common causes
computed tomography. These imaging modalities should
include intra-abdominal inflammation, hollow organ per-
be used to investigate a specific concern and not as a re-
foration, trauma, bowel ischemia, and bowel obstruc-
placement for clinical judgment. Plain radiographs of the
tion. Regardless of the causes of peritonitis, immediate
abdomen may be helpful in the examination of the patient
laparotomy to achieve source control and peritoneal toil
with acute abdominal pain. A single radiographic view of
is the most important part of treatment for preventing
the abdomen is rarely of help. The usual collection of ra-
subsequent serious intra-abdominal sepsis. However, con-
diographic views of the abdomen obtained includes an up-
servative treatment is reserved for those patients with peri-
right view; a view of the kidneys, ureters, and bladder; and
tonitis that is caused by other medical conditions. Iden-
an upright chest radiograph. An inspection should be per-
tification of those cases of peritonitis that will not benefit
formed for detecting the presence of free intraperitoneal
from surgery is necessary.
air, air in the retroperitoneum, patterns of gas distention,
The diagnostic workup of the peritonitis always be-
air-fluid levels, foreign bodies, fecaliths, and stones.10 Free
gins with a precise history taking, a complete physical
intraperitoneal or retroperitoneal air is a definitive diag-
examination, and laboratory studies. The approach to ex-
nosis of hollow organ perforation or abscess formation, and
amining patients with peritonitis via diagnostic imaging
the other findings are used for adjuvant diagnosis.
may change when improved outcomes have been dem-
Laparoscopy has been advocated as a diagnostic mo-
onstrated. Inherent in the evaluation of new technology
dality in the examination of a patient with acute abdomi-
applied to peritonitis is how tests can avoid a misdiag-
nal pain.11-13 Although directly visualizing the abdomi-
nosis or provide an earlier disposition of peritonitis. The
nal cavity might be a valid method of determining the
goal of an imaging study as a diagnostic aid in peritoni-
focus of the inflammation, patients preceded to surgery
tis should be to search for the presence of surgical dis-
or without any abnormal findings would be exposed to
ease. In addition, it should be quick, relatively noninva-
the risks and costs of general anesthesia and diagnostic
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laparoscopy. Several researchers14-17 have advocated the
pathological process in cases of peritonitis but also for its
use of computed tomography as the imaging test of choice
ability to eliminate certain diagnoses, expedite patient care,
in diagnosing peritonitis. However, computed tomogra-
and improve resource allocation. In many cases, the pa-
phy is associated with greater cost, exposure to ionizing
tient’s medical history, clinical examination results, labo-
radiotherapy, and exposure to contrast medium.18 Com-
ratory findings, and the results of plain radiography of the
puted tomography may more or less identify septated peri-
abdomen or chest suffice to indicate the need for urgent
toneal fluid, parietal peritoneum thickening, and infil-
surgery, and an ultrasonographic examination is not indi-
tration of the mesenteric or omental fat, fluid-filled dilated
cated in these patients. However, in other cases, when clini-
loop; it may also demonstrate bowel wall edema and ob-
cal diagnosis is uncertain and treatment is not clear, ultra-
viate the need for laparotomy.14
sonography may identify the precise cause underlying acute
Abdominal ultrasonography has become a diagnos-
abdominal pain that requires surgery. The results of this
tic procedure of increasing importance in patients with acute
study suggest that ultrasonography is a useful adjunct in a
abdomen.19-24 Various reports19-21,24 have shown its benefit
subgroup of patients with peritonitis whose clinical im-
in surgical emergencies when a diagnosis has to be deter-
pression is unclear.
mined rapidly. This study was performed to evaluate the
diagnostic sensitivity of abdominal ultrasonography in the
Reprints: Wei-Jao Chen, MD, PhD, Department of Sur-
diagnosis of peritonitis. In a previous study,25 ultrasono-
gery, National Taiwan University Hospital, No. 7, Chung-
graphic screening led to an earlier diagnosis, but the length
Shan South Road, Taipei, Taiwan, Republic of China.
of hospitalization was not reduced. In this study of 102 pa-
tients, a preoperative ultrasonographic examination accu-
rately detected the cause of peritonitis in 85 (83.3%),
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