Differential diagnosis The differential diagnosis of abdominal pain during pregnancy can be either obstetric/gynecologic or nonobstetric. Nonobstetric causes of abdominal pain include gastroenteritis, urinary tract infections, cholecystitis, pancreatitis, incarcerated or strangulated hernia, bowel obstruction, pulmonary embolism, pneumonia, sickle cell disease, Meckel's diverticulum, and mesenteric adenitis, among others.
Gynecologic and obstetric causes of abdominal pain in the pregnant patient include false labor or Braxton Hicks contractions, ovarian cysts, adnexal torsion, placental abruption, chorioamnionitis, preeclampsia, preterm labor, and salpingitis.
Imaging Graded compression ultrasonography is a noninvasive procedure that should be considered first in the workup of acute appendicitis. Helical CT has been successful in identifying appendiceal changes and may help distinguish simple appendicitis from complicated appendicitis. Helical CT may also identify the location of the appendix in the pregnant patient and help rule out other causes of abdominal pain. A safe level of radiation exposure in pregnancy is 5 rad, which makes CT using 300 mrad an acceptable alternative.4
Management Early surgical intervention for simple appendicitis is the treatment of choice. The goal of therapy is to prevent appendiceal perforation, which carries a significant risk of morbidity and mortality for both the mother and the child. The appendix may be removed safely using laparoscopic techniques through the first trimester, when the gravid uterus is midway between the umbilicus and the pubic symphysis. After the 20th week of gestation, the gravid uterus rises above the umbilicus, making laparoscopic removal hazardous, and an open surgical approach is indicated. A broad-spectrum antibiotic with anaerobic coverage, such as one of the second-generation cephalosporins, is appropriate if perforation has occurred.
When the patient presents with a well-defined, walled-off abscess, as our patient did, percutaneous drainage should be attempted if it can be performed safely. Weighing the risks versus benefits of drainage can help assess whether drainage will be successful in the overall treatment and may determine if other treatment alternatives should be implemented. Once the abscess is localized via CT scan, a percutaneous drain is put in place by an interventional radiologist using aseptic technique with local anesthesia. For optimum access to the appendiceal abscess, a pigtail catheter is placed, utilizing the shortest pathway while avoiding any adjacent structures, including the bowel and vital organs. The quantity of purulent drainage is recorded daily by either the nurse or the patient to determine when the drain can be removed safely. A daily recording or single measurement of less than 20 mL of serosanguineous drainage without purulence usually indicates that the drain can be removed. Pregnant patients whose appendiceal abscess is successfully treated nonoperatively with antibiotics and drainage may be offered an interval appendectomy in 6 weeks or after delivery.
A recent study by Kaminski suggests only a 5% incidence of recurrent appendicitis in patients initially treated nonoperatively. Furthermore, patients who had a recurrent episode of appendicitis requiring appendectomy had a hospital stay of only 4 days, compared with the 6-day stay observed in patients who underwent an elective interval appendectomy.5
Patients presenting with diffuse peritonitis or signs and symptoms of shock should receive aggressive resuscitation, start broad-spectrum antibiotics, and undergo immediate exploration. Fetal distress or signs and symptoms of preterm labor are also indications for immediate surgical intervention.
CONCLUSION
Appendicitis is the most frequent nonobstetric indication for emergent surgical intervention during pregnancy. Patients may present with classic signs and symptoms, including periumbilical abdominal pain that migrates to the right lower quadrant (McBurney point), fever, nausea, anorexia, and leukocytosis, but these clinical findings may be erroneously attributed to the pregnancy itself.
As the pregnancy progresses, the appendix may become displaced cephalad by the growing uterus. This may result in an atypical clinical presentation of acute appendicitis, further complicating and delaying the diagnosis. An extensive differential diagnosis should be entertained, followed by appropriate workup and diagnostic imaging.
Management of appendicitis in pregnant patients includes IV hydration, antibiotics, and close fetal monitoring. When appendicitis is diagnosed early, an appendectomy should be performed. If the appendix has ruptured and formed a well-defined abscess and the patient and fetus are stable, the abscess can be percutaneously drained and antibiotics given. An interval appendectomy may be performed after the baby is born, or the patient can safely be watched and counseled that she has a 5% chance of having another episode of appendicitis in the future. Patients who present with diffuse peritonitis or evidence of fetal distress or preterm labor warrant immediate abdominal exploration and appendectomy. JAAPA
Megan Fulton is lead PA on the trauma/general surgery team, Medical
University of South Carolina, Charleston. Bennett Fontenot is a second-year general surgery resident at the Medical University of South Carolina. Stuart Leon is Associate Professor of Surgery and Medical Director of the Surgery-Trauma ICU at the Medical University of South Carolina. The authors have indicated no relationships to disclose relating to the content of this article.
Steve Wilson, PA-C, department editor
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