Films and Scans
A 27-year-old female with no significant PMH presented to the ED with sudden onset of sharp RUQ abdominal pain. Her pain started two hours prior to admission and radiated to her back and was associated with nausea but not vomiting. She had no complaints of hematemesis, diarrhea, melena, dysuria, or vaginal bleeding or discharge. She reported no fever, chest pain, or shortness of breath. She took no medications and denied alcohol, tobacco or illicit drug use.
Vital signs on admission: T- 36.1 orally, B/P - 119/69, Pulse – 100,
Respirations - 18
Examination of the patient revealed a well-developed 27-year-old woman in acute pain, but otherwise nontoxic. There were no abnormal findings other than tenderness in the RUQ. Guarding was present, but rebound could not be reliably elicited. The remainder of her abdominal exam was normal. The patient was given pain medication and basic labs were drawn, including, of course, an amylase, lipase and a hepatic panel. After this initial evaluation the likely differential included biliary colic, acute cholecystitis, pancreatitis, peptic ulcer disease, gastritis, esophageal spasm, and possibly pneumonia. The patient’s age and lack of other findings makes cardiac and/or pulmonary disease less likely. Similarly, with such localized pain, appendicitis, nephrolithiasis, ovarian cyst or torsion, and UTI seemed much less likely and became low on the differential. The patient’s lab work returns and is significant for a WBC count of 19,400 and an ANC of 14,500. However, her amylase, lipase and hepatic panel were normal. And surprisingly, her BHCG was positive.
A quantitative BHCG is ordered, which came back at 6,452. While waiting for the blood test results a quick look with the new ultrasound, just purchased by the department, was obtained. Surprise number two. It clearly demonstrated free fluid in Morrison’s pouch. After making sure that the patient was hemodynamically stable and had at least one functioning large bore IV, a formal pelvic ultrasound was ordered from radiology which confirmed the diagnosis of ruptured ectopic pregnancy. The uterus was empty and there was a hemorragic left adnexal mass. The patient was promptly taken to the OR where over a liter of fresh blood was evacuated from her abdomen. The patient was previously unaware that she was pregnant.
Ectopic pregnancy is the leading cause of death in first-trimester pregnancy-related deaths, and accounts for 2% of all pregnancies. Risk factors include pelvic inflammatory disease, use of fertility drugs, progesterone IUD, and previous surgical procedures to the fallopian tubes, though this patient had none of these. Blood in the abdomen can cause peritoneal and diaphragmatic irritation that can mimic pain from a variety of other etiologies. Although no exact number exists, BHCG levels as low as 1,000-2,000 are generally correlated with an identifiable intrauterine pregnancy on pelvic ultrasound. Therefore, an empty uterus and/or adnexal mass, then, is highly suspicious for an ectopic pregnancy.
Obstacles in making the diagnosis of an ectopic pregnancy include patient presentation and diagnostic work-up. Only half of all women with ectopic pregnancies present with vaginal bleeding, and while abdominal pain is the most common complaint at 75%, the location of pain (as in the teaching case file) may not indicate an ectopic pregnancy. In addition, the ability of urine BHCG tests to detect early pregnancies has been questioned by several studies. The first day of a missed period may coincide with a BHCG of only 12mIU/mL, while many urine tests cannot even reliably confirm pregnancy at a BHCG level of 100mIU/mL. It is therefore imperative that we familiarize ourselves with our department’s limitations if a urine test is being ordered to detect pregnancy.
Including ectopic pregnancy in the differential for any woman of child-bearing age with abdominal pain should be obvious. Although a GYN etiology for this patient’s pain seemed somewhat less likely on initial exam, including one simple test in the initial evaluation prevented what could have become a life threatening delay in her workup.
Even with patients where the diagnosis appears to be obvious, an inexpensive pregnancy test remains an essential part of evaluating any woman of childbearing age, no matter how unlikely a gynecological etiology seems. Rarely are there such simple tests to rule out potentially life-threatening conditions, and it would be to our patients’ and our own detriment not to keep this in mind.
Jyoti Mahapatra, MD, is an emergency medicine instructor at the University of Nebraska Medical Center