It is repeatedly-and appropriately-emphasized that pregnancy makes the diagnosis of appendicitis more diicult. Nausea and vomiting accompany normal pregnancy, but also, as the uterus enlarges, the appendix commonly moves upward and outward from the right lower quadrant (Baer, 1932; Erkek, 2015; Pates, 2009). Another often-stated reason for late diagnosis is that some degree of leukocytosis accompanies normal pregnancy. For these and other reasons, pregnant womenespecially those late in gestation-frequently do not have clinical findings "typical" for appendicitis. Thus, it commonly is confused with cholecystitis, labor, pyelonephritis, renal colic, placental abruption, or uterine leiomyoma degeneration.
Most reports indicate increasing morbidity and mortality rates with advancing gestational age. nd as the appendix is progressively delected upward by the growing uterus, omental containment of infection becomes increasingly unlikely. It is indisputable that appendiceal perforation is more common during later pregnancy (Abbasi, 2014). In the studies by Andersson (2001) and Ueberrueck (2004), the incidence of perforation was approximately 8, 12, and 20 percent in successive trimesters.
Persistent abdominal pain and tenderness are the most reproducible findings. Right-lower quadrant pain is the most frequent, although pain migrates upward with appendiceal displacement CMourad, 2000). For initial evaluation, sonographic abdominal imaging is reasonable in suspected appendicitis, even if to exclude an obstetrical cause of pain (Butala, 2010). hat said, graded compression sonography is diicult because of cecal displacement and uterine imposition (Pedrosa, 2009). Appendiceal computed tomography is more sensitive and accurate than
FIGURE 54-4 Anterior-posterior magnetic resonance image of a periappendiceal abscess in a midtrimester pregnancy. The abscess is approximately 5 x 6 cm, and the appendiceal lumen (arow) is visible within the right-lower quadrant mass. The gravid uterus is seen to the right of this mass.
sonography to conirm suspected appendicitis (Katz, 2012; Raman, 2008). Specific views can be designed to diminish fetal radiation exposure (Chap. 46, p. 907). It is generally accepted that when available, MR imaging is the preferred modality for evaluation of suspected appendicitis in pregnancy (Fig. 54-4). MR imaging has high diagnostic yield and accuracy, and it also provides alternative diagnoses (Fonseca, 2014; Theilen, 2015). One metaanalysis cited positive-and negativepredictive values for MR imaging of 90 and 99.5 percent, respectively (Blumenfeld, 2011). Burke and associates (2015) reported similar indings. Using a decision-analysis model, CT and MR imaging were found to be cost efective (Kasten berg, 2013). This was verified in the clinical study of more than 7000 cases reported by Fonseca and coworkers (2014).
When appendicitis is suspected, treatment is prompt surgical exploration. Although diagnostic errors may lead to removal of a normal appendix, surgical evaluation is preferable to postponed intervention and generalized peritonitis (Abbasi, 2014). In earlier reports, the diagnosis was veriied in only 60 to 70 percent of pregnant women. As indicated above, however, with CT and MR imaging, these igures have improved (Blumenfeld, 2011; Theilen, 2015). Still and importantly, the accuracy of diagnosis is inversely proportional to gestational age.