Medical Student Clinical Pearl – December 2020

Marisa O’Brien

@mbob58

MD Candidate, Class of 2021

Memorial University of Newfoundland

Reviewed and Edited by Dr. David Lewis

All case histories are illustrative and not based on any individual

 

---

Case Report

A 36-year-old G2P1 female presented to the Emergency Department following a pre-syncopal episode at work. The patient noted a sudden onset of significant abdominal cramping, nausea, and vaginal bleeding with clots that morning followed by an episode of lightheadedness while sitting at her desk. The patient denied any loss of consciousness, no dyspnea, no chest pain, no palpitations, and no fevers/chills. She had no known allergies and no current medications. She was a non-smoker and denied any alcohol or drug usage.

The patient’s past medical history was significant for recent treatment with methotrexate for an ectopic pregnancy eight days prior. The patient had a history of amenorrhea for 7 weeks and a serum β-hCG of 302 mlU/mL at that time. A transvaginal ultrasound was performed at 8 weeks for abdominal pain and light spotting which revealed an IUD in situ with no evidence of an intrauterine pregnancy. An early ectopic pregnancy was diagnosed and the patient was consented to receive medical management with methotrexate. She was followed up with serial β-hCG’s which gradually, but slowly, trended down to 110 mIU/ml by day 6. The patient noted slight abdominal cramping and PV bleeding following the methotrexate however this had settled after 3 days with no ongoing symptoms until today.

On initial assessment, the patient appeared well, no acute distress, and all vital signs were stable.  The abdominal exam revealed bowel sounds present in all four quadrants and the abdomen was tympanic to percussion. On palpation the abdomen was soft and nondistended with LLQ and suprapubic tenderness however, no guarding or rebound tenderness was appreciated.

Initial investigations included a CBC, β-hCG, PT & PTT, type and screen, urinalysis, EKG, & POCUS.

 

---

Definition

An ectopic pregnancy occurs when a fertilized egg implants at a site other then the endometrium of the uterus, most commonly the fallopian tubes. They often present as vaginal bleeding and/or abdominal pain in the setting of a positive β-hCG.¹

A critical complication is a ruptured ectopic pregnancy which occurs by erosion through the tissue the zygote has implanted in resulting in intraabdominal bleeding from the exposed vessel and possible hypovolemic shock.² Rupture should be suspected in patients presenting with hemodynamic instability including syncope, hypotension, and tachycardia. However, young healthy females may appear vitally stable initially due to compensatory mechanisms. Additional physical exam findings suggestive of a ruptured ectopic pregnancy include severe abdominal pain with guarding or rebound tenderness and abdominal distention. Pain may radiate to the shoulder due to irritation of the diaphragm from blood in the peritoneal cavity.^1,3

 

---

Risk factors for ectopic pregnancy⁴

• Previous ectopic pregnancy
• Prior fallopian tube surgery
• Previous pelvic or abdominal surgery
• Sexually transmitted infections
• Pelvic inflammatory disease
• Endometriosis
• Cigarette smoking
• Maternal age > 35 years
• History of infertility
• Assisted reproductive technology (IVF)

 

• IUD reduces the risk of both intrauterine and ectopic pregnancy, but in cases where it fails the risk of ectopic is proportionally higher

 

---

Differential diagnosis for vaginal bleeding in early pregnancy¹:

• Physiologic
• Spontaneous abortion
• Cervical, vaginal, or uterine pathology
• Subchorionic hematoma
• Heterotopic pregnancy
• Gestational trophoblastic disease

 

---

Sonography

According to the discriminatory zones, an intrauterine pregnancy is expected to be visualized on a transvaginal ultrasound at β-hCG levels of 1500 – 2000 mlU/mL and on a transabdominal ultrasound at levels of 4000 – 6500 mlU/mL.⁵

Gestational Age	Β-hCG range (mlU/mL)
<1 week	5 – 50
1-2 weeks	50 – 500
2-3 weeks	100 – 5000
3-4 weeks	500 – 10,000
4-5 weeks	1000 – 50,000
5-6 weeks	10,000 – 100,000
6-8 weeks	15,000 – 200,000
8-12 weeks	10,000 – 100,000

Table 1: Estimated β-hCG levels in relation to gestational age.³

In the first trimester of a normal pregnancy, the serum β-hCG should increase by ≥ 53% every 48 hrs until 41 days of gestation.^1,3 Serum β-hCG will then continue to rise more slowly until approximately 10 weeks after which it will begin to decline until reaching a plateau. Serum β-hCG levels are noted to raise more slowly in an ectopic pregnancy, thus a slower rate of increase, plateau, or decline in serum β-hCG in the first 41 days suggests a possible miscarriage or ectopic pregnancy.¹

Note on β-hCG Discriminatory Zones

The value of discriminatory zones in the emergency management of ectopic pregnancy is low, with many considering it unreliable and potentially dangerous. In short, a low β-hCG does not exclude an ectopic. This useful post provides a good summary on ectopic rule-out in the ED:

Rule Out Ectopic in the Emergency Department

 

An intrauterine pregnancy is confirmed by visualization of a gestational sac and a yolk sac within the uterus (juxtaposed to bladder).¹ A gestational sac alone is not sufficient for diagnoses of an intrauterine pregnancy as it may be a pseudogestational sac formed by hormonal stimulation from an ectopic pregnancy.⁵ Additionally, if an intrauterine pregnancy is visualized, a heterotopic pregnancy should also be considered.¹ The risk of heterotopic pregnancy when conceived normally is estimated to be 1 in 30,000.

Figure 1: Visualization of an intrauterine pregnancy on a transvaginal ultrasound.³

 

 

Structure	Transvaginal Ultrasound	Transabdominal Ultrasound
Gestational Sac	4.5-5 weeks	5.5-6 weeks
Yolk Sac	5-5.5 weeks	6-6.5 weeks
Fetal Pole	5.5-6 weeks	7 weeks
Cardiac Activity	6 weeks	7 weeks
Fetal Parts	8 weeks	>8 weeks

Table 2: Ultrasound findings based on gestational age.⁵

 

---

Diagnosis of Ectopic Pregnancy

An ectopic pregnancy is suspected in all women with a positive pregnancy test when no intrauterine pregnancy is visualized on ultrasonography. A low β-hCG or declining β-hCG does not exclude an ectopic. Ultrasound findings of an ectopic pregnancy may include an extrauterine gestational sac or embryonic cardiac activity outside of the uterus, a complex adnexal mass, or intraperitoneal fluid.³

From emupdates.com

 

---

Management of Ectopic Pregnancy

Is the patient unstable?

• If the patient is hemodynamically unstable (tachycardia or hypotension or pale or syncopal) then commence immediate resuscitation (IV Access, CBC, type & crossmatch,  iv fluids, transfusion, etc) and stat consult to ObGyn.

In stable patients

• Consult ObGyn
• The gold-standard of treatment for ectopic pregnancy is surgical management however, treatment options include expectant, or medical management.⁶ Medical management with methotrexate, a folic acid antagonist that inhibits DNA synthesis and cell production, has a higher success rate when initiated at lower β-hCG levels. Methotraxate is initiated if β-hCG is <5000 mlU/mL and is reserved for those with reliable follow up as β-hCG levels are required to be trended until they are undetectable. Individuals with renal disease, hepatic disease, active pulmonary disease, or immunodeficiencies are not candidates for methotrexate.^3,7 Individuals who do not meet the criteria for medical management, are hemodynamically unstable, have failed methotrexate, or a ruptured ectopic is suspected, will receive surgical management.⁶

 

---

Case Report Continued

The patient was hemodynamically stable on presentation. Her vital signs were normal. As part of the initial assessment, PoCUS was used to further evaluate for the presence of free fluid in the abdomen or pelvis. Free fluid was identified in the RUQ in both Morrison’s pouch and surrounding the caudal tip of the liver. Intraperitoneal fluid was also seen in the LUQ in both the subphrenic and splenorenal spaces. Free fluid was also visualized in Douglas’ pouch in the pelvic view.

RUQ

LUQ

Pelvis

 

Throughout the PoCUS examination the patient remained well appearing, however she had become hypotensive with a blood pressure of 90/53 mmHg. Her initial bloodwork had come back at this time revealing a β-hCG of 32 mlU/mL and a Hgb of 67 g/L. The patient received 1g of TXA, and a 1L bolus of normal saline while PRBC’s were ordered. She was documented to be Rh+ thus, she did not require RhoGAM (anti-D immune globulin). An urgent consultation to Obstetrics and Gynecology was made following the visualization of intraabdominal fluid and the patient underwent an exploratory laparotomy shortly after.

 

---

Key Points

• Ectopic pregnancy should be considered in the differential diagnosis of any female patient, of childbearing age, presenting with abdominal pain, syncope or shock
• An Intrauterine contraceptive device does not exclude an ectopic
• Unless a previous ultrasound has documented the presence of an intrauterine pregnancy, an empty uterus in a patient with a positive pregnancy test should be considered to be a possible ectopic until ruled out
• An intrauterine pregnancy on ultrasound requires the following to be confirmed:
  • A gestational sac and a yolk sac, in the uterus which is juxtaposed to the bladder
  • or a gestational sac containing a normal fetal pole, in the uterus which is juxtaposed to the bladder
• A low β-hCG or declining β-hCG does not exclude an ectopic
• Medical management of ectopic pregnancy with methotrexate requires close follow-up. Failure can occur. Ruptured ectopic pregnancy can still occur.

 

---

Further Reading

Ectopic Pregnancy and Ruptured Ectopic: Pitfalls in Diagnosis

ED Rounds – Early Pregnancy

The Pregnant ED Patient – A Compendium of Pearls

 

 

---

References

1. Tulandi, T. (2020, November 2). Ectopic pregnancy: Clinical manifestations and diagnosis. Retrieved from: https://www.uptodate.com/contents/ectopic-pregnancy-clinical-manifestations-and-diagnosis?search=ectopic%20pregnancy&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H1
2. Toy, E.C., Simon, B.C., Takenaka, K.Y., Liu, T.H., & Rosh, A.J. (2017). Ectopic Pregnancy. Case Files Emergency Medicine. (4^th, pp. 369-376). McGraw-Hill Education.
3. Hang, B.S. (2016). Obstetrics and Gynecology. Tintinalli’s Emergency Medicine: A Comprehensive Guide. (8^th, pp. 629-633). McGraw-Hill Education.
4. The American College of Obstetricians and Gynecologists. (2018, February). Retrieved from: https://www.acog.org/womens-health/faqs/ectopic-pregnancy
5. Leonard, N.J. (2019, January 23). The Pregnant Pelvic POCUS. EMRounds. Retrieved from: https://emrounds.org/the-pregnant-pelvic-pocus/
6. Tulandi, T. (2020, March 31). Ectopic pregnancy: Choosing a treatment. Retrieved from: https://www.uptodate.com/contents/ectopic-pregnancy-choosing-a-treatment?search=ectopic%20pregnancy&topicRef=5407&source=see_link#H2976630177