Ectopic Pregnancy—Part II: Diagnostic Procedures and Imaging

Abstract

SUMMARYEctopic pregnancy is an increasingly common and potentially catastrophic condition in which the patient often presents to the ED with abdominal pain or vaginal bleeding. Recent developments in the laboratory (sensitive PhCG assays, progesterone assays), in ultrasonogra‐phy (transvaginal probes, Doppler ultrasonography), and in the combination of modalities (discriminatory zone of PhCG for ultrasono‐graphic evidence of IUP) have allowed the earlier diagnosis of ectopic pregnancy, with the potential for a reduction in maternal mortality and morbidity.Understanding the strengths and limitations of the variety of diagnostic modalities available will allow the clinician to formulate a rational strategy for the early diagnosis of ectopic pregnancy. Numerous algorithms have been developed. All begin wiht high clinical suspicion for women of reproductive age with abdominal/ pelvic pain or vaginal bleeding. Pregnancy testing with a sensitive PhCG qualitative test is next. For stable patients found to be pregnant, zoography generally follows (often first Tran abdominally then transvaginally). Unstable patients require immediate resuscitation and gynecology consultation; invasive diagnostic methods may supplant laboratory studies and sonography. Unclear cases may necessitate the use of quantitative PhCG (discriminatory zone), other pregnancy hormones (progesterone), invasive procedures (laparoscopy, culdocentesis, D&C), or observation (serial ßhCGs). A suggested algorithm incorporating these elements is shown (Fig. 1).

Cornual Ectopic Pregnancy Diagnosed by Emergency Physician-Performed Bedside Ultrasound in the Emergency Department

“…In particular, women of childbearing age with an acute non-traumatic abdomen are at particularly high risk for an ectopic pregnancy (1-4). Bedside emergency ultrasound should be performed by the emergency physician in the pregnant patient to rule in an intrauterine pregnancy; there is increasing literature showing that emergency physicians have high specificity for diagnosing intrauterine pregnancy with ultrasound (90 -95% specific) (3,(5)(6)(7). For the emergency physician, an intrauterine pregnancy is diagnosed when there is a yolk sac, a fetal pole, or visualization of an intrauterine embryonic heartbeat (3,6).…”

“…Bedside emergency ultrasound should be performed by the emergency physician in the pregnant patient to rule in an intrauterine pregnancy; there is increasing literature showing that emergency physicians have high specificity for diagnosing intrauterine pregnancy with ultrasound (90 -95% specific) (3,(5)(6)(7). For the emergency physician, an intrauterine pregnancy is diagnosed when there is a yolk sac, a fetal pole, or visualization of an intrauterine embryonic heartbeat (3,6). Thus, in patients with no elevated risk of heterotopic pregnancy (no history of ectopic or in-vitro fertilization treatments), the presence of an intrauterine pregnancy essentially rules out an ectopic pregnancy (8).…”

Hemorrhagic shock from a ruptured ectopic pregnancy in a patient with a negative urine pregnancy test result

“…3 Most management guidelines use a sensitive qualitative urine β-hCG test as the first step in the evaluation of possible ectopic pregnancy. [5][6][7][8] A negative test result generally eliminates further consideration of this diagnosis. It is estimated that up to 1% of ectopic pregnancies will be associated with β-hCG values of less than 20 mIU/mL and will therefore escape detection by most urine β-hCG assays, which promote sensitivities of greater than or equal to 25 mIU/mL urine.…”

“…A negative test result is used to exclude the diagnosis of pregnancy and thereby a possible ectopic gestation. [5][6][7][8] The following case is a rare emergency department presentation of a patient with hemorrhagic shock caused by ruptured ectopic pregnancy in the setting of a repeatedly negative urine pregnancy test result and a very low quantitative β-hCG level.…”

Answer

“…A normal TVS (empty uterus with no pelvic pathology) combined with a beta-hCG less than 1500 mIU/ml is compatible with early viable intrauterine pregnancy (IUP), nonviable IUP or ectopic pregnancy, 3 and 13% to 40% of patients in this group have an ectopic. 4 Unstable patients and those with significant abdominal tenderness should have immediate obstetrical consultation, but in stable patients with normal TVS and low beta-hCG, it is reasonable to perform serial beta-hCGs.…”