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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

Diagnosis of acute appendicitis in pregnant women: value of sonography.

The diagnosis of acute appendicitis in pregnant women often is difficult to make on the basis of clinical findings, and radiologic examination is limi...
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