It seems like your entire shift has been non-specific abdominal pain, peppered with a few non-cardiac chest pains and some non-organic headaches that are only relieved by Dilaudid. No one feels your pain from taking care of patients that don’t really need to be in the ED in the first place, but hey, it’s job security, right? So you suck it up and grab the next chart in the to-be-seen box. The chief complaint reads “gas pains.”
“Great.” you mutter under your breath. Then you smile, thinking that at least this patient has a somewhat original complaint and has given her condition enough thought to make a supposition about what the cause of their discomfort may be. Then, you wax sagacious, thinking to yourself that no normal person would actually come to the ED for pain that they truly thought was due to gas. You conclude that behind curtain number three you will either encounter a total moron, or a stoic individual who actually has something serious going on, but hopes that they just have gas.
You walk into the room and introduce yourself to your patient. She happens to be a 40-year-old female attorney with her husband at the bedside. She states that she ate a huge Greek salad, with a lot of onions in it, for lunch, and now she has terrible gas pains. The pain started in the supra-public area, but thereafter spread to her entire abdomen. She also feels a bit light-headed, but that is actually improving. There has been no fever, vomiting, diarrhea, cardiac or pulmonary symptoms. She is otherwise healthy with no prior medical problems or prior surgeries. Her only medication is prenatal vitamins, which she is taking because she and her husband are trying for their first child. She states that her last period was about 1 month ago. She rates her pain as “5 or 6 out of 10” and she thinks this is all gas because onions always give her gas. When asked if she ever had to see a doctor in the ED before for gas pains, she answers, “Well… no, but I wasn’t going to come here. I went to an urgent care and they referred me to you.”
On physical exam, her heart rate is 112 and her BP is 133/71. The rest of her vitals and physical exam are essentially normal, except she has involuntary guarding in all four quadrants of her abdomen. While you percuss about, you ask if it hurts, and she answers, “not that bad” meanwhile wincing each time you press. It’s not your first rodeo, so you know you need to be extra cautious with a stoic patient like this. Frequent flyers in the ED who have multiple visits, but never seem to have an actual acute medical condition may eventually burn you if you let your guard down. They tend to be overly dramatic and helped only by opiates or benzodiazepines. However, it is with the stoic patient that you are most likely to miss or delay an important diagnosis. If they’ve never been to your ED before for the current complaint or, even more telling, they have their hospital gown on backwards, beware! These are the ones in which you have to assume the worst-case scenario until proven otherwise.
This is exactly what you do. Thinking “ruptured ectopic,” you are glad to have a patient that you may actually be able to help. You order labs, a type & cross and some fentanyl. Then, you briskly wheel over the portable ultrasound machine and take the two images shown at below.
What part of the body is each image from, and what does it show? Is your suspicion supported? What should be your next move, and what other test results do you need to wait for before proceeding?
See NEXT page for case conclusion.
Catching an Ectopic Pregnancy on Bedside Ultrasound
Image 1 is of the most important place to start scanning when you are worried about intra-abdominal bleeding. It shows Morrison’s pouch in between the liver capsule and the right kidney. This is usually the most dependent area of the abdomen in a supine patient. Sometimes blood won’t actually push this far back, and the anechoic fluid is actually seen a bit more anteriorly, or only at the inferior tip of the liver. In this image though, the blood appears black and has moved all the way back to the posterior part of the hepatorenal recess. When the fluid stripe reaches about 1cm in width, it corresponds to approximately one liter of intraperitoneal free fluid.
Image 2 is the pelvis shown longitudinally with the indicator pointing toward the patient’s head (cephalad). Just posterior to the bladder, you see a dark heterogeneous area, which looks suspicious. It does not look like really dark anechoic free fluid like you are used to seeing with acute intraperitoneal bleeding, but you are concerned because there is so much of it. As you fan through, you notice that the blood is not only collecting in the anterior cul-de-sac (as seen in Image 2), but also in the posterior cul-de-sac. You obtain careful transabdominal views of the uterus, and note that the uterus is empty and there is no sign of an intrauterine pregnancy. As you are trying to find the adnexa on a transabdominal view, the patient’s urine dip comes back positive for beta-hCG.
Your suspicion is confirmed. Your stoic patient who initially said, “I have terrible gas pains,” really meant to say, “Help me, can’t you see I’m bleeding to death.” In a case like this, you don’t need to, and shouldn’t, wait for the pregnancy test to come back before calling in your OB surgeon. The patient may have a ruptured hemorrhagic ovarian cyst or a ruptured ectopic pregnancy. Either way, she needs operative intervention with that amount of free fluid in her pelvis. Call your consultant early and let them “own” the rest of the time spent before she goes upstairs. Getting the surgeons involved early can help expedite patient care, and once they physically see the patient, they may be prompted to make different decisions based on their own clinical gestalt. It’s hard to argue with black and white images of a large amount of intraperitoneal free fluid.
As with most ectopic pregnancies, they turn south, and typically, very quickly. Fortunately for this patient, she was resuscitated with blood and rushed to surgery where they found a ruptured ectopic and four liters of blood in her abdomen. Maintaining a high level of suspicion and performing a bedside ultrasound ultimately saved this patient’s life.
Continue to next page for Pearls and Pitfalls
Pearls & Pitfalls for Ultrasound Evaluation for an Ectopic Pregnancy
1. Assess Stability: Do not send an unstable patient to radiology. If you have the skills, perform a bedside ultrasound yourself and call your surgeon early. If not, have your ultrasound tech scan at the bedside. For unstable patient’s, call your surgeon early, even before all of your diagnostic tests come back.
2. Start at Morison’s Pouch: Begin by scanning the hepatorenal recess (Morison’s Pouch). This is the most dependent position when the patient is lying supine and free fluid may be noted here first. Unfortunately, your hospital ultrasound tech may not include this area in a pelvic ultrasound, but you won’t make that mistake. If you see fluid here, call for help ASAP. Any patient with a positive pregnancy test and free fluid visible on bedside ultrasound should be suspected of having a RUPTURED ectopic pregnancy until proven otherwise. In many ectopic pregnancies, free fluid is the only sonographic abnormality appreciated. Even if the pregnancy test is not resulted yet, free fluid here is reason enough to call OB and prep your patient for the OR. Of all of the causes of non-traumatic intraperitoneal free fluid in an otherwise healthy patient, a ruptured ectopic pregnancy or a ruptured hemorrhagic ovarian cyst are the two most likely diagnoses.
3. Transabdominal Scan: If Morrison’s Pouch is clean, evaluate the pelvis via a transabdominal approach. To get the best views, the patient should ideally have a full bladder to serve as an acoustic window. Look for hypoechoic free fluid in the vesicouterine and rectouterine spaces, and assess the uterus for the presence or absence of an intrauterine pregnancy. In a ruptured ectopic, all you may see is a confusing mess of heterogeneous clotted blood that can even make it hard to delineate the uterus. If you have done plenty of scans of the normal pelvis, you will be able to tell that “something just looks wrong” though you may have a hard time accurately determining what exactly you are looking at.
4. Transvaginal Scan: If adequate images are not obtainable via the transabdominal approach, a transvaginal ultrasound can be performed at the bedside. Cover the endovaginal transducer with a gel filled sheath and apply a copious amount of clear gel to the outside of the sheath. Insert and advance the transducer with the indicator marker pointing anteriorly towards the patient’s pubic symphysis. Alternatively, you may let the patient insert the probe herself as this method is often less uncomfortable. Scan through the uterus in this sagital plane, noting the presence or absence of an intrauterine pregnancy. Note if you see any free fluid in the anterior or posterior cul-de-sac.
5. Optional - Look for the Ectopic: It is often possible to visualize the ectopic pregnancy during a quick transvaginal bedside scan. Rotate the probe 90° counter-clockwise and point the indicator marker towards the patient’s right side. Trace the broad ligament of the uterus out toward the ovaries, which lie just medial to the iliac vessels. Look for any complex adnexal masses or tubal rings.
6. Don’t Delay: You do not need to see the ectopic to diagnose it. If you see free fluid, get on the phone to OB, and don’t delay patient care.
7. Scan Normal Pelvises: Whenever you scan for alternate indications, practice looking at the pelvis with trans-abdominal approach. The more normal studies you look at, the more likely you are to recognize when something isn’t right.
Brady Pregerson manages a free on-line EM Ultrasound Image Library and is the editor of the Emergency Medicine Pocketbook series. For more information visit EMresource.ORG.
Teresa S. Wu is the Associate Residency Director, and Director of Ultrasound and Simulation Programs and Fellowships, for the Maricopa Emergency Medicine Program in Phoenix, Arizona. She is an Associate Professor in Emergency Medicine at the University of Arizona, School of Medicine-Phoenix.