Drs. Abdi, Stacy, Mailhot, and Perera once again describe a case where ultrasound made the difference in clinical management of a patient. Their case is published in WestJEM with a great tutorial video (see below) accompanying it.
Emergency physicians perform bedside ultrasound in 1st trimester abdominal pain and vaginal bleeding to “rule in” an intrauterine pregnancy, but the better way to describe how we think about it is “ruling out” any signs of an ectopic pregnancy. By doing it in the emergency department, it has been shown to decrease length of stay of these patients, and increase their satisfaction. With a full bladder, a transabdominal pelvic ultrasound is performed with a regional assessment of the pelvic organs to visualize for confirmation of an intrauterine pregnancy (yolk sac or fetal pole within a gestational sac in the uterus). You may need to empty the bladder and perform a transvaginal ultrasound if the above does not provide the information you need (I bring the ultrasound machine with me to the bedside when I first meet them so that I can do the history, physical, and ultrasound right off the bat). If there is an identifiable pregnancy then an evaluation for a fetal heart and its rate is assessed in order to characterize it as a “live” intrauterine pregnancy. But, if there is no contents within the gestational sac (a potential pseudosac), or if there is no gestational sac, then the concern for ectopic pregnancy still exists. Of course, in a recent post, we discuss that even those cases may turn out to have a normal pregnancy despite an elevated beta hcg level, calling into question whether the “discriminatory zone” should be used to guide our management.
Let’s go back to their case: The brilliance of this case, however, isn’t that they found an ectopic or illustrate what I describe above, instead it illustrates that there are other diagnoses that may be apparent on ultrasound that is causing the pelvic pain and vaginal spotting. And, if you don’t look, or if you are unfamiliar with what you are seeing on the screen, you may miss it – or mistakingly call it an intrauterine pregnancy.
The case: 32 yrs old G1P0 known pregnant at 7weeks by last menstrual period with lower pelvic cramping and vaginal spotting. A bedside ultrasound is performed and the video below describes what they saw…. read more on the case here.
Since “being pregnant” is a diagnosis that can be made, we shouldn’t stop there after we have identified an intrauterine pregnancy. We shouldn’t simply state “you’re pregnant” and discharge them home without further consideration of the etiology of their pelvic pain. Something else may be causing it. (to read about other cases using pelvic ultrasound, go here.) Other findings/diagnoses to consider in 1st trimester pelvic pain or vaginal spotting:
1. Ovarian cyst or torsion (see this case report in J of EM that discussed exactly why you should continue to evaluate with bedside US).
5. Infection – anywhere (Pelvic inflammatory disease, tubo-ovarian abscess, UTI, colitis/proctitis, etc)
6. Heterotopic pregnancy- consider in patients on fertility drugs