Ectopic Pregnancy on US (Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org. From the case rID: 8161)

Definition: Embryo implantation outside of the endometrial cavity

Background: (Alkatout 2013)

  • Ectopic pregnancy occurs in up to 2% of pregnancies.
  • It is the leading cause of 1st trimester death and causes 0.5 deaths/100,000 live births.
  • Ectopic Location (Arleo 2014)
    • Greater than 95% of extrauterine implantations occur in the fallopian tube.
    • Interstitial pregnancies: occur in to the most proximal segment of the fallopian tube within the uterine wall
    • Cornual pregnancies occur in the upper and lateral portion of the uterus.
    • Rare cervical pregnancies implant in the uterine endocervix. They may be confused with an aborting intrauterine pregnancy (IUP) residing in the cervix and may lead to massive hemorrhage if disturbed.
  • Heterotopic pregnancy: An ectopic pregnancy in conjunction with an IUP
    • Natural conception rate: 1/30,000
    • Assisted reproduction rate: 1/100
  • Ectopic pregnancy rupture is often associated with profound hemorrhage, which may be fatal if rapid surgical intervention isn’t undertaken
  • The vast majority of deaths occur prior to hospitalization or just after to arrival to the emergency department. (Anderson 2004)

Clinical Presentation:

  • Classic Triad
    • Abdominal pain
    • Vaginal bleeding
    • Missed menstrual period
  • Patient’s typically present 6-8 weeks after the last normal menstrual period
  • Signs and symptoms suggestive of rupture
    • Vital sign abnormalities
      • Hypotension
      • Tachycardia
      • Shock
    • Lightheadedness/syncope
    • Cool, pale skin
    • Nausea + emesis
    • Severe abdominal pain
  • Referred pain
    • Diaphragmatic irritation from free blood in the peritoneal space may present as shoulder pain
    • Referred neck or rectal pain are reported
  • Vagal stimulation from intra-peritoneal blood can present as hypotension and bradycardia

Selected Differential Considerations:

  • OB/GYN conditions: Spontaneous abortion (of normal IUP), septic abortion, early normal IUP, ovarian cyst, ovarian/fallopian torsion, necrotic myoma, PID/TOA
  • Others: Appendicitis, cystitis, obstructed viscus, perforated viscus, pyelonephritis, vascular hemorrhage/ischemia.

Free Fluid in Morrison’s Pouch (AHC Media)

Evaluation of Unstable Patients

  • Rapid identification is paramount
    • Ruptured ectopic should be considered in any hemodynamically unstable woman of child bearing age
    • Presence of free fluid in absence of trauma in this group should be considered ectopic pregnancy until proven otherwise
  • Basic Management
    • ABCs, Large bore (> 18 gauge) IV X 2, Supplemental O2 if necessary
    • Approach similar to exsanguinating trauma patient
  • Key actions:
    • Perform a FAST exam
      • Positive result requires immediate OB/Gyn or surgical consultation for surgical exploration
      • Can improve sensitivity by placing patient in Trendelenburg position
    • Hemodynamic instability should trigger massive transfusion protocol
    • Start resuscitation with O negative blood (start with crystalloid resuscitation if blood not immediately available)

Ectopic Pregnancy US (Case courtesy of Dr Maulik S Patel, Radiopaedia.org. From the case rID: 46956)

Evaluation of Stable Patients

  • Rapid, unexpected decompensation can occur
  • Pertinent History/Risk Factors: prior genital tract infection(s), prior ectopic pregnancy, prior dilatation and curettage or tubal ligation, current IUD, assisted reproduction, age >35, tobacco use, progestin-only contraception
  • Assessment
    • Vital signs: may be normal early in the course of significant bleeding, particularly in young patients due to compensatory mechanisms
    • Physical examination: lower abdominal tenderness or diffuse tenderness with or without rebound or guarding, depending on extent of hemorrhage
    • FAST exam (for free fluid)
  • Laboratory evaluation
    • Quantitative pregnancy test
    • CBC (to aid in assessment of blood loss)
    • Basic metabolic panel (renal function important consideration in medical management)
    • Type and screen (with Rh factor status)
    • PT/PTT and fibrinogen in unstable patients (assessment for DIC)
  • Imaging
    • Transabdominal US can rapidly identify IUP but can miss early pregnancy
    • Transvaginal US (TVUS) is more sensitive for diagnosing an IUP and for finding an ectopic

  • Heterotopic Pregnancy (Ultrasound Image Gallery)

    Management based on imaging

    • Ultrasound with (+) IUP
      • Ectopic highly unlikely (possible in heterotopic)
      • Manage as threatened Ab
      • Consider hetertopic pregnancy in patients with assisted reproduction
    • Ultrasound with (+) ectopic
      • OB/Gyn consultation for further management
    • Ultrasound with no IUP or ectopic (indeterminate US) AND no free fluid
      • β-hCG level < 1500 (Condous 2005)
        • May be early IUP
        • Typically will get repeat β-hCG in 48 hours to look for appropriate rise and repeat US
      • β-hCG level > 1500
        • Risk of ectopic rises as TVUS usually locates IUP above this level
        • Management will be based on shared decision making with patient and OB/Gyn
          • Medical abortion (methotrexate)
          • Expectant management (repeat US and β-hCG)
  • Medical management with methotrexate
    • Eligible Patients:
      • Hemodynamically Stable,
      • Hcg <5000,
      • Need to comply with treatment and follow up,
      • No fetal cardiac activity
    • Contraindications:
      • Renal insufficiency
      • Immunodeficiency
      • Active Pulmonary Disease
      • Peptic Ulcer Disease
      • Hypersenstivity to MTX
      • Heterotopic Pregnancy with viable IUP
      • Breastfeeding
    • Dosing
    • Disposition
      • Patients with ectopic pregnancy may be discharged after administration of methotrexate
      • Indeterminate US
        • Hemodynamically stable patients may be discharged
        • Close follow up is mandatory

Take Home Points

  • Ecoptic pregnancy is the leading cause of 1st trimester maternal death
  • Always consider the diagnosis of an ectopic pregnancy in any woman of child bearing age presenting with abdominal pain, vaginal bleeding, and missed period
  • Hemodynamically unstable patients need rapid diagnosis and stabilizing treatment
  • Involve consulting services early on in management course

Read More:

LITFL: Ectopic Pregnancy

EM Updates: Rule Out Ectopic in the Emergency Department

EM: RAP: Episode 79 – Ectopic Pregnancy

EM: RAP: C3- Frist Trimester Vaginal Bleeding

References:

ACEP Clinical Policies Subcommittee (Writing Committee) on Early Pregnancy et al. Clinical Policy: Critical Issues in the Initial Evaluation and Management of Patients Presenting to the Emergency Department in Early Pregnancy. Ann Emerg Med. 2017;69:241-250.e20. PMID: 22921048

Alkatout I et al. Clinical diagnosis and treatment of ectopic pregnancy. Obstet Gynecol Surv 2013;68:571. PMID: 23921671

American Institute of Ultrasound in Medicine, ACEP. AIUM practice guideline for the performance of the focused assessment with sonography for trauma (FAST) examination. J Ultrasound Med 2014;33:2047. PMID: 18204028

Anderson FW et al. Sudden death: ectopic pregnancy mortality. Obstet Gynecol 2004;103:1218. PMID: 15172855

Arleo EK, DeFilippis EM. Cornual, Interstitial, and Angular Pregnancies: Clarifying the Terms and a Review of the Literature. Clin Imaging. 2014;38:763-70. PMID: 25156020

Barnhart KT. Clinical practice. Ectopic pregnancy. N Engl J Med. 2009;361:379-387. PMID: 19625718

Condous G, Kirk E, Lu C, et al. Diagnostic accuracy of varying discriminatory zones for the prediction of ectopic pregnancy in women with a pregnancy of unknown location. Ultrasound Obstet Gynecol 2005; 26:770. PMID: 16308901

Doubilet PM et al. Diagnostic criteria for nonviable pregnancy early in the first trimester. N Engl J Med. 2013;369:1443-1451. PMID: 24106937

Ley EJ et al. Emergency department crystalloid resuscitation of 1.5 L or more is associated with increased mortality in elderly and nonelderly trauma patients. J Trauma 2011;70:398. PMID: 21307740

Lipscomb GH. Medical therapy for ectopic pregnancy. Semin Reprod Med 2007; 25:93. PMID: 17377896

Parks JK et al. Systemic hypotension is a late marker of shock after trauma: a validation study of ATLS principles in a large national sample. Am J Surg 2006; 192:727. PMID: 17161083

Rana P et al. Ectopic pregnancy: a review. Arch Gynecol Obstet. 2013;288:747-57. PMID: 23793551

Samal SK, Rathod S. Cervical ectopic pregnancy. J Nat Sci Biol Med. 2015;6:257-60.PMID: 25810679

Stovall TG, Ling FW. Single-dose methotrexate: an expanded clinical trial. Am J Obstet Gynecol 1993; 168:1759. PMID: 8317518