A 36-year-old woman, gravida 3 para 2, at 32 weeks gestation comes to the emergency department due to abdominal pain. The patient's symptoms started a day ago as mild right-sided abdominal pain. Since then, the pain has become increasingly severe and is accompanied by fever, heartburn, and diarrhea. The patient has had no contractions, vaginal bleeding, or leakage of fluid. Fetal movement is normal. The pregnancy has been uncomplicated. She has no chronic medical conditions and has had no surgeries. The patient takes a daily prenatal vitamin and does not use tobacco, alcohol, or illicit drugs. Temperature is 38.9 C (102 F), blood pressure is 140/80 mm Hg, and pulse is 112/min. Fetal heart rate monitor shows a baseline of 160/min, moderate variability, and no decelerations. Tocometry shows no contractions. Cardiopulmonary examination reveals tachycardia but a regular rhythm and no rubs. The lungs are clear to auscultation. Abdominal examination reveals tenderness throughout the right lower quadrant and flank but no uterine fundal or costovertebral angle tenderness. There is no rebound or guarding. McBurney point is nontender. Pelvic examination reveals no adnexal masses or tenderness. Laboratory results are as follows: Item 1 of 2 Which of the following is the best next step in diagnosing this patient's condition?

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Explanation: This pregnant patient's fever, right-sided abdominal pain, and leukocytosis are concerning for possible acute appendicitis. Pregnant patients with acute appendicitis can have a typical presentation (eg, anorexia, periumbilical pain that migrates to the right lower quadrant). However, due to the displacement of the appendix by the growing uterus during pregnancy, atypical presentations are common. The upward displacement of the appendix results in decreased contact between the appendix, parietal peritoneum, and omentum. Therefore, patients often have no peritoneal signs (eg, no rebound or guarding) and no McBurney point tenderness. Patients with atypical presentations require imaging; first-line imaging during pregnancy is a graded compression abdominal ultrasound due to the low risk of radiation exposure to the fetus. When ultrasound findings are inconclusive, an abdominal MRI is indicated. Appendicitis diagnosed and treated prior to perforation has no associated obstetric complications. However, the atypical presentation during pregnancy can result in delayed diagnosis, thereby increasing the risk for appendiceal perforation. Appendiceal perforation increases the risk for spontaneous abortion, preterm labor, and preterm delivery. (Choice A) A CT scan is the first-line imaging modality for appendicitis in nonpregnant patients; however, it is avoided during pregnancy due to the risk of fetal radiation exposure. If an ultrasound is nondiagnostic and an MRI is unavailable, a CT scan can be performed. (Choice C) Neisseria gonorrhoeae and Chlamydia trachomatis nucleic acid amplification testing is a component in the evaluation of chorioamnionitis (eg, intrauterine infection). This patient has no uterine fundal tenderness. (Choice D) Urine culture is indicated for acute pyelonephritis, which presents with fever and right lower quadrant and flank pain. This patient has no costovertebral angle tenderness, making this diagnosis less likely. (Choice E) A urine protein-to-creatinine ratio is indicated to evaluate for preeclampsia, which can present with heartburn and right upper quadrant pain (eg, hepatic involvement); however, there is no associated fever or leukocytosis. Educational objective: Appendicitis during pregnancy can have an atypical presentation, including right-sided abdominal pain with no peritoneal signs or McBurney point tenderness. In atypical presentations, imaging with a graded compression abdominal ultrasound is indicated. References: Acute appendicitis in pregnancy: literature review. (http://www.ncbi.nlm.nih.gov/pubmed/26107368)

A 36-Year-Old Woman, Gravida 3 Para 2, at 32 Weeks