Case

A 32 year old pregnant woman presents to the emergency department for a repeat beta-hCG. The patient reports persistent but decreasing vaginal bleeding and crampy lower abdominal pain. The last menstrual period was 11 weeks ago. The patient first presented 3 days earlier to an outside hospital with vaginal bleeding and cramping for 3 weeks. Radiology ultrasound at that time showed no evidence of intrauterine pregnancy, a complex right ovarian cyst, and only minimal free fluid. She was discharged home with instructions to follow up for repeat beta-hCG testing 48 hours later.

Physical exam reveals an awake, alert, cooperative and well-appearing female in no acute distress. The initial vital signs are: temp, 97 °F; blood pressure, 140/86; pulse, 90; and respirations, 20. Cardiovascular, pulmonary and abdominal exams are unremarkable. Pelvic exam is significant for a closed cervical os actively oozing blood. There is no cervical motion tenderness or adnexal tenderness or mass.

The emergency department physician performs a transabdominal ultrasound to evaluate for the presence of an intrauterine pregnancy. The patient is placed in the supine position and a 4 MHz transducer is placed just superior to the pubic symphisis in the sagittal plane. The bladder is found to be adequately full and the uterus, cervix, cul-de-sac and adnexae are fully visualized by sweeping the probe left, right, caudad and cephalad (Transabdominal Long).

The physician then explains the transvaginal ultrasound procedure and obtains verbal consent. In the longitudinal scanning plane the uterus, bladder, cul-de-sac and adnexa are fully visualized by sweeping the probe the full width of the organs. The probe is rotated 90 degrees counterclockwise into the transverse scanning plane. The left adnexa is unremarkable (L Ovary).

However, within the right adnexa is a small 0.88 x 0.97 cm fluid filled sac circumferentially surrounded by vasculature on color doppler imaging (R Adnexal Mass Measured and Color Doppler).

• View R Adnexal Mass Measured and Color Doppler Video

Discussion

The percentage of ectopic pregnancies has been steadily increasing since 1970 occurring in 2% of pregnancies today. Despite a 90% drop in mortality from 1970-1992, ectopic pregnancy remains the leading cause of pregnancy related death in the first trimester, accounting for 13% of all pregnancy related deaths (1;2). It is frequently misdiagnosed on the initial ED visit remaining a major source of liability for emergency physicians (3). The classical clinical presentation is described as amenorrhea, abdominal pain and vaginal bleeding. However this triad is actually more often descriptive of a threatened abortion than ectopic pregnancy. Patients can present with hemodynamic instability and hemorrhage or have completely normal vital signs and pelvic exams. 50% of patients have no risk factors, and no combination of absence or presence of signs or symptoms has been shown to reliably exclude suspected ectopic pregnancy (4). Limited ED ultrasound allows the emergency physician to safely and quickly exclude ectopic pregnancy by identifying an intrauterine pregnancy.

The earliest definitive limited ED ultrasound findings consistent with an intrauterine pregnancy is an intrauterine gestational sac surrounding a yolk sac. This is seen on transvaginal exam between 5 and 6 weeks and on transabdominal exam by 7 weeks. Later findings include the fetal pole/embryo and cardiac activity visible at 6 and 8 weeks on transvaginal and transabdominal exams respectively. At least 5 mm of myometrial tissue must be visualized surrounding the gestational sac on all sides to ensure that it is intrauterine and not interstitial.

Though the primary purpose of the limited ED ultrasound in suspected ectopic pregnancy is to identify an IUP, the emergency physician will often find signs of an abnormal pregnancy, and on rare occasions identify the ectopic itself. Findings suspicious for an ectopic pregnancy include large amounts of free fluid in the cul-de-sac, adnexal masses, and gestational sac-like fluid collections and occasionally fetal cardiac activity located outside the uterus (2). The positive “ring-of-fire” sign is consistent with an ectopic pregnancy surrounded by hypervascular tissue. This sign consists of high velocity low resistance peri-trophoblastic (placental) blood flow appears as a constant “glowing” color on color flow examination and is seen in up to 85% of ectopic pregnancies (5).

Limited ED ultrasound performed by emergency medicine physicians to identify intrauterine pregnancies in women with first trimester vaginal bleeding has been shown to reduce visit times by 60 to 120 minutes, particularly for patients who present in the evening or at night (6;7). It also reduces the need for consultations by 85% and the need to call in off-site radiology technicians (5). Identifying an IUP effectively rules out ectopic pregnancy with a negative predictive value of 100%, the only caveat being the possibility of heterotopic pregnancy in women undergoing fertility treatment. The sensitivity and specificity of ED ultrasound for detecting ectopic pregnancy have been reported at 90% and 88%, respectively (8). The sensitivity and specificity of ED ultrasound for detecting ectopic pregnancy have been reported at 90% and 88%, respectively (9).

Emergency physicians credentialed according to ACEP guidelines perform limited ED pelvic ultrasound at Cook County Hospital to rapidly identify intrauterine or ectopic pregnancy in patients presenting with first trimester pelvic pain or bleeding. In stable patients, if an IUP is not identified on transabdominal ultrasound, the transvaginal approach is attempted. If an IUP is identified outpatient follow-up is arranged. If the findings are consistent with an ectopic or indeterminate, beta-hCG levels are obtained, OB/GYN is consulted and a formal radiology ultrasound is performed. In the unstable pregnant patient, a FAST scan is performed in addition to pelvic ultrasonography. Moderate or large amounts of free fluid without evidence of an IUP prompt emergent OB/GYNE consultation and transfer to the operating room for definitive diagnosis and management.

Conclusion

After visualizing the ectopic pregnancy, the emergency physicians immediately consulted the OB/GYN service. Admission occurred hours sooner than if she had waited for a formal radiology ultrasound. The repeat beta-hCG was 5886 up from 5714 three days earlier. A formal radiology ultrasound confirmed our results and the patient underwent laparoscopy while in the hospital.

References

1. Houry DC AJ. Acute Complications of Pregnancy. In: Marx J, editor. Rosen's Emergency Medicine. Philledephia: Mosby, 2006: 2739-2760.
2. Nordenholz K. First Trimester Pregnancy. In: Lippincott Williams & Wilk, editor. Practical Guide to Emergency Ultrasound. 2006: 123-160.
3. Della-Giustina D, Denny M. Ectopic pregnancy. Emerg Med Clin North Am 2003; 21(3):565-584.
4. Della-Giustina D, Denny M. Ectopic pregnancy. Emerg Med Clin North Am 2003; 21(3):565-584.
5. Pellerito JS, Taylor KJ, Quedens-Case C, Hammers LW, Scoutt LM, Ramos IM et al. Ectopic pregnancy: evaluation with endovaginal color flow imaging. Radiology 1992; 183(2):407-411.
6. Blaivas M, Sierzenski P, Plecque D, Lambert M. Do emergency physicians save time when locating a live intrauterine pregnancy with bedside ultrasonography? Acad Emerg Med 2000; 7(9):988-993.
7. Della-Giustina D, Denny M. Ectopic pregnancy. Emerg Med Clin North Am 2003; 21(3):565-584.
8. Durham B, Lane B, Burbridge L, Balasubramaniam S. Pelvic ultrasound performed by emergency physicians for the detection of ectopic pregnancy in complicated first-trimester pregnancies. Ann Emerg Med 1997; 29(3):338-347.
9. Della-Giustina D, Denny M. Ectopic pregnancy. Emerg Med Clin North Am 2003; 21(3):565-584.

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