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539
Diagnosis Pregnant
of Acute Appendicitis Women: Value of
in
Sonography
Hyo Keun Lim1 Sang Hoon Bae Gwy Suk Seo
OBJECTIVE. The diagnosis of acute appendicitis in pregnant women often is difficult to make on the basis of clinical findings, and radiologic examination is limited because of the potentially hazardous effects of radiation. This study was done to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women. SUBJECTS AND METHODS. We obtained sonograms in 45 pregnant women with clinically suspected acute appendicitis. Our sonographic technique included gradedcompression scanning. The left lateral decubitus position was used in the third trimester of gestation. The sonographic criterion for the diagnosis of acute appendicitis was visualization of an incompressible appendix with a maximal diameter greater than 7 mm. We correlated the sonographic findings with the surgical findings in 22 cases and with the results of clinical follow-up in 23 cases. RESULTS. Sonography could not be used to make the diagnosis in three (7%) of 45 patients because the size of the gravid uterus prevented use of the graded-compression technique. These three patients were in the third trimester of pregnancy (>35 weeks’ gestation). Sonographic findings were used as a basis for diagnosis in 42 cases. Acute appendicitis was diagnosed on the basis of sonograms in 16 patients, and in all but one of these patients, acute appendicitis was confirmed by surgical and pathologic findings. In the 42 cases in which the imaging findings indicated the diagnosis, the overall
sensitivity
of sonography
was 100%,
98%. CONCLUSION. Our experience valuable procedure for detecting difficulty in performing it during
AJR
159:539-542,
Acute
September
appendicitis
the specificity
suggests
that
was 96%, and the accuracy
graded-compression
acute appendicitis the third trimester
sonography
in pregnant women of pregnancy.
despite
was is a
technical
1992
in pregnant
women,
particularly
when
perforation,
peritonitis,
or both occur,
has been associated with increases in premature labor and fetal and maternal death. The myriad of abdominal problems that are common in pregnant women and anatomic changes that include altered location of the appendix and loss of elasticity in abdominal muscles are factors that contribute to the difficulty in diagnosis [i , 2].
Radiologic Received February vision April 1 , 1992 Presented
Copenhagen,
24, 1992;
at the World
September
accepted
Congress
after re-
in Ultrasound,
1991.
imaging
in pregnant
women
thought
limited because of the potentially hazardous effects resolution sonography with the graded-compression
ualization
of the acutely
inflamed
appendix.
Several
to have acute
appendicitis
is
of radiation. Real-time hightechnique allows direct vis-
reports
[3-6]
have suggested
dress reprint requests to H. K. LJm.
that high-resolution sonography is fairly accurate in the diagnosis of acute appendicitis. To our knowledge, the value of sonography in the diagnosis of acute appendicitis in pregnant women has not been reported in the English-language literature except for one case report by Coady at al. [7]. This study was done to
0361 -803X/92/1 593-0539 CAmerican Roentgen Ray Society
assess the value of graded-compression appendicitis in pregnant women.
1All authors: Department of Radiology, Kangdong Sacred Heart Hospital, Hallym University, 445 Kil-dong Kangdong ku, Seoul 134-701 , Korea. Ad-
sonography
for the diagnosis
of acute
LIMETAL.
540
Subjects
AJR:159,
examination
and Methods
indicative
Dunng a 48-month women with clinically
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2i-40
period, we obtained sonograms in 45 pregnant suspected acute appendicitis. The patients were
years old (mean,
25 years). Twenty-eight
were in the first
trimester of pregnancy (up to 1 3 weeks), 1 0 were in the second trimester (1 4-27 weeks), and seven were in the third trimester (28 weeks or more). All patients had abdominal pain: 34 (76%) in the right lower quadrant, nine (20%) in the right flank, and two (4%) in the right upper quadrant. The patients initially consulted their obstetricians, who determined if any abnormality was present in the fetus, uterus, or placenta. Patients with any abnormality in these areas and with no possibility of acute appendicitis were not included in the study. After the obstetrician’s evaluation, a general surgeon examined
the patients
and requested
sonography
for the assessment
of acute
immediately
had surgery.
sonographic
findings
and
Other
who
had
September
patients
who
1992
had no
improvement
in signs
and symptoms were clinically followed up with close observation until the signs and symptoms completely resolved. If signs and symptoms progressed during clinical follow-up, the patient had surgery. The sonographic
findings
were
correlated
with
the
surgical
results
in 22
cases and the results of clinical follow-up in 23 cases. Clinical followups were performed while the patient was being treated conservatively,
with
resolved.
close
observation
until
The final diagnosis
symptoms
of acute
and
signs
appendicitis
completely
was made
on the
basis of pathologic findings in the patients who had surgery. The diagnosis of appendicitis in patients whose sonograms showed no evidence of appendicitis was based on clinical findings: complete resolution of signs and symptoms during close clinical observation for more than 1 week.
appendicitis.
All sonograms
were obtained
(UM-4 unit, Advanced method of examination
with a 5-MHz
Technology
linear-array
Laboratories,
transducer
Seattle,
WA). The
was similar to the graded-compression technique introduced by Puylaert [3]. However, because of the size of the gravid uterus, it was difficult during the late second trimester or the third trimester of pregnancy to perform the graded-compression technique when the woman was supine. Consequently, we were unable to use sonography for diagnosis in the first three women in the study. Therefore, for women in the late second trimester or third trimester, we imaged the cecum and appendix with the patient in the
left lateral decubitus
or left posterior
oblique position.
The sonographic criterion for diagnosis of acute appendicitis was visualization of an incompressible appendix with a maximal diameter
greater than 7 mm. The presence collection
with an inflamed
of a loculated
appendix
indicated
periappendiceal appendiceal
tion. We considered the sonographic findings nondiagnostic cecum could not be adequately visualized or compressed. inflamed
appendix
could
as a fluid collection
be seen, the presence
in the peritoneal
cavity,
if the If the such
of complications
suppurative
fluid
perfora-
areas of
inflammation, and abscess formation was determined. After the appendix was evaluated, we checked for disease of the pelvic cavity and for fetal well-being. For evaluation of the pelvic cavity, the patient’s bladder was partially full and a 3.5-MHz transducer was used. At the time of sonographic examination, we had no knowledge
of clinical findings,
laboratory
diagnosis
was based
sonographic
findings
or progressive
findings,
on sonographic indicative
of acute
signs and symptoms
or the surgeon’s findings
only.
appendicitis
opinion. Our
All patients and
with
continuous
during and after the sonographic
Results Sonography in our
was nondiagnostic
series.
In one
patient,
in three (7%) of 45 patients adequate
visualization
and
compression of the cecum were not possible because the gravid uterus was markedly enlarged. Surgery confirmed acute appendicitis. Sonograms in the other two patients were nondiagnostic for similar reasons; these two patients were clinically followed completely after
up, and their signs and symptoms resolved i and 2 days. All three patients with nondi-
agnostic
were in the third trimester
tation
studies
in two cases,
36 weeks’
gestation
(37 weeks’ in one case).
gesIn i 6
(38%) of the other 42 patients, sonographic findings indicated a diagnosis of acute appendicitis. The maximal diameter of the appendix in these patients was 8-i 6 mm (mean, i 2 mm). In 1 5 (94%)
of these
i 6 patients,
acute
appendicitis
was
surgically confirmed (Fig. i). One of these i 5 patients had a perforated appendix, and a localized abscess formation seen sonographically
(Fig.
2)
was
confirmed
at
surgery.
Sono-
graphic findings were false-positive for the diagnosis of acute appendicitis in one patient who had a sonographically visible incompressible appendix with maximal diameter of 8 mm (Fig. 3). The patient’s signs and symptoms had subsided by the time
of sonographic
formed.
examination,
In 26 (62%) of 42 patients,
and surgery
no evidence
was
not per-
of a visible
Fig. 1.-Acute appendicitis in a 27year-old pregnant woman (8 weeks’ gestation). A and B, Transverse (A) and sagittal (B) sonograms show an inflamed appendix (between cursors). Surgery showed acute suppurative appendicitis without
perforation.
AJR:159,
SONOGRAPHY
September1992
Fig. 2.-Perforative
appendicitis
OF APPENDICITIS
541
IN PREGNANCY
in a
29-year-old pregnant woman (20 weeks’ gestation). A and B, Transverse (A) and sagittal (B) sonograms of right lower quadrant
c ;
of abdomen
show a markedly inflamed (arrows) and a loculated, septated fluid collection (FL) in superior aspect of gravid uterus (UT). Surgery showed perforated appendix with periappendiceal abscess.
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appendix
e.
t
Fig. 3.-False-positive
sonogram
#{149}
;‘:i; .
“
in
a 25-year-old pregnant woman (20 weeks’ gestation). Transverse sonogram of right lower quadrant of abdomen shows an incompressible, tubular structure with maximal outer diameter of 8 mm (a sonographic indicative of acute
:,
,
:-
finding usually appendicitis).
Patient’s symptoms and signs had subsided
by time of examination
and span-
taneously resolved during hospitalization; surgery
was
not performed.
This
case was considered false-positive cause of clinical graphic findings.
course,
Fig. 4.-Acute
despite
besono-
appendicitis
in a 28.
year-old pregnant woman (29 weeks’ gestation). Graded compression technique could not be used with this patient supine because of large gravid uterus; therefore, sonogram was obtamed with patient in left posterior oblique
position.
Right
flank
was
used
as an acoustic window. Oblique sonogram of right flank appendix (arrows) Surgery confirmed
shows
an inflamed
and cecum acute
(CE).
suppurative
appendicitis without perforation, and cecum and appendix were in right upper quadrant of abdomen. LE = edge of liver.
incompressible
appendix
was seen on sonograms.
these did not have surgery, dicitis
was seen at clinical
and no evidence follow-up
i week
Twenty
of
of acute appento 2 months
later
(mean, 3 weeks). In one of these patients, a distal ureteral stone with mild hydronephrosis of the right kidney was seen on the initial sonogram; the stone passed spontaneously after 1 day, and signs and symptoms resolved completely. This was confirmed by follow-up sonography 2 days later. In the remaining six patients, diagnoses based on sonographic findings included complicated ovarian cyst in five and hollow viscus perforation plicated ovarian
in one. At surgery, cyst were confirmed
the diagnosis of comas torsion of ovarian
For the 42 cases in which the sonographic findings indicated the correct diagnosis, the sensitivity of sonography was
i 00%, the specificity
was 96%, and the overall accuracy
was
98%. The positive predictive value was 94%, and the negative predictive value was i 00%. In our series, clinical follow-up until delivery showed no maternal deaths, one spontaneous abortion, and one premature delivery. The patient with a spontaneous abortion was confirmed at surgery as having acute appendicitis without
perforation, and the patient with premature delivery had no evidence of appendicitis on follow-ups performed until the
cyst, and the diagnosis of hollow viscus perforation was verified as perforation of a duodenal ulcer with generalized
time of delivery. We found no relationship between acute appendicitis and suboptimal outcome; however, it was not our intent to make this comparison, and the small number of
peritonitis.
cases precluded
All six of these
patients
had a normal
appendix.
it.
LIM ETAL.
542
Discussion
Several authors
Acute appendicitis
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occurring
during
is the most common
pregnancy
[8].
surgical emergency
Delayed
diagnosis,
by the
presence
of a gravid
uterus
particu-
[1 1]. The
location
of the appendix varies. As the uterus enlarges, the appendix commonly moves upward and outward toward the flank, so that pain and tenderness may not be prominent in the right lower quadrant. In this study, this was true in patients with surgically proved acute appendicitis. Eleven patients had pain in the right lower quadrant of the abdomen among i 6 patients with surgically proved acute appendicitis: nine (90%) of i 0 patients in the first trimester of gestation, two (50%) of four patients in the second trimester, and none of two patients in the third trimester. The reported accuracy of clinical assessment alone in the preoperative
diagnosis
ofacute
appendicitis
during
pregnancy
is as low as 58-68%. The overall fetal mortality after removal of the appendix has been reported as 20%, and fetal mortality seems to be related to the severity of the disease [1 2-i 4]. Saunders and Milton [i 4] reported that diagnostic laparotomy, including unnecessary maneuvers such as removing a normal appendix, increased the premature labor and fetal mortality rates. In the 42 cases in our series in which it was used successfully, the diagnostic accuracy of gradedcompression
sonography
was
high:
i 00%
sensitivity,
96%
and 98% overall accuracy. The sensitivity and rates in previous studies were 75-89% and 95100%, respectively [3-6]. The overall results in our study are
specificity, specificity similar
to those
graded-compression gestation.
of others,
despite
sonography
the difficulty
of performing
during the third trimester
have indicated
in the first two trimesters
larly when perforation, peritonitis, or both occur, has been associated with increases in premature labor and fetal and maternal death [2, 9]. As the appendix is pushed progressively higher by the growing uterus, containment of the infection by the omentum becomes increasingly unlikely, and appendiceal rupture causes generalized peritonitis [i 0]. The diagnosis of acute appendicitis is difficult to make in pregnant women. Signs and symptoms, findings on physical examination, and laboratory findings may be obscured or altered
AJR:159,
of
Graded-compression sonography has been of value in the diagnosis of acute appendicitis [3-6]. However, use of this technique with the patient supine is difficult during the late second trimester and third trimester of pregnancy because the large size of the gravid uterus does not allow adequate compression. This caused three sonographic examinations to be nondiagnostic in our series. Since then, for women in the late second trimester or third trimester, we place the patient in the left posterior oblique or left lateral decubitus position, which allows displacement of an enlarged uterus and use of the graded-compression technique without difficulty. Using this technique, we successfully examined the next four patients who were in the third trimester of pregnancy (Fig. 4).
the disease
September
1992
is most prevalent
[i 5, 1 6], so the use ofthis
alternative
technique usually should be unnecessary. One perplexing pitfall in diagnosis is that displacement of the appendix by the gravid uterus moves the somatic component of pain and the point of maximal tenderness to a higher and more lateral position in the abdomen. In 1932, Baer et al. [i 6] described the changes in the position and direction
of the appendix
as pregnancy
advanced
in a large
series of pregnant women with surgically confirmed acute appendicitis. If we had difficulty locating the cecum and appendix, we referred to the findings of Baer at al. Although a large-scale study would be required for confirmation, it appears the number of nondiagnostic studies can be reduced by using the graded-compression technique with the patient
in the left posterior
oblique
or left lateral
decubitus
position. Our results show that sonography can be a valuable procedure for detecting acute appendicitis in pregnant women. The results are accurate despite difficulty performing the procedure during the third trimester of pregnancy, and no radiation is involved.
REFERENCES 1 . Schwartz SI, Shires GT, Spencer FC. Principles of surgery. In: Schwartz SI, ed. Appendix. New York: McGraw-Hill, 1988: 1321 -1 324 2. Cunningham FG, McCubbin JH. Appendicitis complicating pregnancy. Obstet Gynecol 1975;45:415-420 3. Puylaert JBCM. Acute appendicitis: US evaluation using graded compression. Radiology 1986;158:355-360 4. Jeffrey RB Jr, Laing FC, Lewis FR. Acute appendicitis: high-resolution realtime US findings. Radiology 1987;163:11-i4 5. Puylaert JBCM, Rutgers PH, Lalisang RI, et al. A prospective study of ultrasonography in the diagnosis of appendicitis. N EngI J Med 1987;317:666-669 6. Abu-Yousef MM, Bleichen JJ, Maher JW, lkdaneta LF, Franken EA Jr, Metcalf AM. High-resolution sonography of acute appendicitis. AJR
1987;149:53-58 7. Coady DJ, Snyder JR, Subramanyam B. Appendiceal abscess in pregnancy: diagnosis by ultrasound. JCU 1986;14:70-71 8. Gomez A, Wood M. Acute appendicitis during pregnancy. Am J Surg 1979;137: 180-1 83 9. Masters K, Levine BA, Gaskill HV, Sirinek KR. Diagnosing appendicitis during pregnancy. Am J Surg 1984:148:768-771 10. Cunningham FG, Macdonald PC, Gant NF. Williams obstetrics, 18th ed. Englewood Cliffs, NJ: Prentice-Hall, 1989:832 1 1 . Bailey LE, Finley AK Jr, Miller SF, et al. Acute appendicitis during pregnancy. Am Surg 1986;52:2i8-221 1 2. Priddle HD, Hesseltine HC. Acute appendicitis in the obstetric patient. Am J Obstet Gynecol 195i;62:150-155 1 3. Bryan WM. Surgical emergencies in pregnancies and in the puerperium. Am J Obstet Gynecol 1955;70: 1204-1 213 1 4. Saunders P, Milton PJD. Laparotomy during pregnancy: an assessment of diagnostic accuracy and fetal wastage. BMJ 1973:3:165-167 15. Brant HA. Acute appendicitis in pregnancy. Obstet Gynecol 1967;29: 130-1 38 1 6. Baer JL, Reis RA, Arens RA. Appendicitis in pregnancy with changes in position and axis of normal appendix in pregnancy. JAMA 1932;98: 1359-1364