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A 20-year-old woman, G1P0 at 17 weeks' gestation, presented to the emergency department (ED) 10 hours ago complaining of right-sided abdominal pain accompanied by nausea and two episodes of vomiting. She is afebrile at present, blood pressure is 130/72 mm Hg, heart rate is 86 beats per minute (bpm), and respiratory rate is 20 breaths per minute. She weighs 198 lb (90 kg) and is 5 ft 7 in (169 cm) in height, with a body mass index (BMI) of 31 kg·m−2. She admits to right-sided tenderness to palpation localized to the inguinal region. She underwent an ultrasound evaluation by an obstetrician who did not find any cause for the pain related to her pregnancy. The general surgery service was consulted, and it is their opinion that the patient has appendicitis and will require a laparoscopic appendectomy.
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Her pregnancy has been unremarkable up to this point and is otherwise healthy. She has had no previous anesthetics and no family history of anesthesia-related problems. She takes prenatal vitamins, denies any allergies, does not smoke or drink alcohol, and takes no drugs. Physical examination of her heart and lungs is normal. Her airway examination reveals a Mallampati Class IV airway with limited mouth opening, normal range of motion of head and neck, full dentition, and minimal mandibular protrusion. The thyromental distance is 5 cm and the hyomental distance is 3 cm. There are no other abnormalities in her history or physical examination.
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53.2.1 What Is the Incidence of Appendicitis in Pregnancy?
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Appendicitis has an incidence of approximately 1 in 1500 pregnancies, with appendectomy being the most common non-obstetric surgical procedure during pregnancy.1,2 The relative incidence is estimated to be 30% in the first trimester, 45% in the second trimester, and 25% in the third trimester3; and the most common predictor of fetal-maternal mortality is appendiceal perforation, with an estimated risk of 43%, and the risk of perforation increases with increasing gestation and delay in diagnosis.4,5 The estimated risk of fetal loss with appendiceal perforation is 36%.6
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53.2.2 How Is Appendicitis Diagnosed during Pregnancy?
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Anatomic and physiologic changes accompanying pregnancy make diagnosis of appendicitis challenging, therefore a careful history and physical examination, combined with a high index of suspicion, is required. The appendix is pushed superiorly and laterally with advancing gestation. However, according to studies, 84% of pregnant patients present with right lower quadrant pain.3,5 The usual clinical signs and diagnostic tests may be confounded by the physiologic and anatomic changes accompanying pregnancy. Ultrasound examination may be useful to identify a normal appendix and rule out other causes of abdominal pain in this patient population. However, due to the size of the uterus, it may be difficult to localize the appendix during the third trimester.4 Diagnostic imaging using helical CT scanning has been ...