Ticking timebombs: ectopic pregnancy

Introduction

An ectopic pregnancy is simply an extrauterine pregnancy. The vast majority (96%) occur in the fallopian tube, however other sites include cervix, cesarean scar (hysterotomy), ovarian, or even abdominal. Very rarely, there can be both an intrauterine and ectopic pregnancy (heterotopic). Failure to manage this common pathology leads to significant morbidity and mortality.

In this document, we will review the presentation, diagnosis, and approach to management for ectopic pregnancy.

 

Presentation

Most commonly, females will present with:

-Vaginal bleeding (76% of patients)

                  -there is no measured amount of bleeding that is associated more with ectopics. Ranges from scant to heavy.

-Generalized abdominal pain (66%). Often non-focal tenderness on exam.

                  -there is no pattern to the pain. No published data on one particular location of the pain either.

-Rupture in 18% of patients. Peritoneal signs are often present. Patient refuses to move.

A significant, and frightening, number of females may be asymptomatic as well.

Symptoms typically develop around 6-8 weeks after last menstrual period. Women may misinterpret their vaginal bleeding associated with the ectopic as their “normal menses”.

Typical symptoms of pregnancy can also occur: breast tenderness, polyuria, nausea/vomiting.

 

Multiple resources state that the diagnosis of ectopic pregnancy should be considered in any female with vaginal bleeding or abdominal pain… let’s expand that and make it easier.

You need to rule out ectopic pregnancy in ANY FEMALE OF REPRODUCTIVE AGE. We aren’t saying you need to do major workups, but if a female of reproductive age presents to the ED, have a very low suspicion for ordering a urine point of care pregnancy test.

 

Therefore, here’s some major complaints we always order a UPT for: syncope or near-syncopal symptoms, abdominal pain, chest pain, nausea/vomiting, dizziness, lightheadedness, any GU complaint.

There might be others we left out, but these are the classic ones.

 

BIG questions to ask patients with +UPT:

-Gravidity and parity, history of prior ectopics (duh), birth control status, usage of in vitro fertilization, prior history of STDs, PID, surgical history.

Pelvic exam should be performed but suffers from relatively poor specificity and sensitivity. Your goal is to assess for presence of bleeding, its quantity, and confirm that the uterus is the source of bleeding.

 

Diagnosis

Workup of ectopics can quickly get… algorithmic and tedious. Here’s an overview to keep you grounded:

1)      Confirm patient is pregnant (UPT)                  If negative UPT this conversation is over.

2)      Is the patient hemodynamically stable?      If not, then “hold on to your butts” (to quote Samuel L Jackson)

3)      Order a serum hCG, blood type, CBC, CMP      The blood type is the most commonly forgotten test

4)      Perform bedside US vs order formal study

a.      Determine intrauterine vs ectopic pregnancy

b.      Coordinate management strategy with Ob/gyn

 

Boring, but necessary stuff you must know…

Human chorionic gonadotropin (hCG) is secreted into maternal circulation after implantation (~6 days after ovulation). Normally, hCG should double ~48 hours during the first 30 days. A slower rise is concerning for ectopic pregnancy or early intrauterine demise, but not confirmatory. A decline is concerning for failed pregnancy.

hCG levels are NOT useful to estimate gestational age after 3 weeks post-conception.

After peaking at ~60-90,000 mili-international units around 8-10 weeks, hCG levels fall off and stay at ~12,000 until term.

If urine hCG is positive, get a serum hCG. CBC, blood type and screen, CMP. If unstable, send a crossmatch as well. Rh-D status is critical to know in these patients.

 

Hemodynamically unstable and +UPT with no palpable fundal height: This is an ectopic pregnancy until proven otherwise. The workup is simple. Send the labs we discussed above.

Most critically, do not delay in performing a Bedside Gyn US with FAST exam to look for rupture, ovarian pathology, or intrauterine pregnancy (transvaginal likely needed to visualize if <4-6 weeks).

Follow aggressive resuscitation algorithms (2 IVs, blood products), and promptly alert Ob/Gyn consultant.

 

Ultrasound

Transvaginal (TVUS): the best test to effectively exclude an ectopic pregnancy. There are only 3 possible options that can occur:

Option 1: Gestational sac with a yolk sac or embryo in the uterus = intrauterine pregnancy

Option 2: Gestational sac with or without yolk sac outside the uterus = ectopic pregnancy

Option 3: No pregnancy is identified = nondiagnostic

Most common finding that confirms ectopic pregnancy: extraovarian adnexal mass (89% of positive cases).

The presence of a gestational sac alone does not confirm an IUP!

Option 1: ectopic pregnancy is effectively ruled out.

Option 2: move forward with medical or surgical management of ectopic pregnancy.

Option 3: if no pregnancy is identified (either IUP or ectopic), it is likely because gestation is too early to be visualized on ultrasound. This is a pregnancy of unknown location, and 8-40% turn out to be ectopic. Serial measurements of hCG should occur with a discussion to repeat TVUS in the future. See algorithm below for details.              

 “Discriminatory zone”: this phrase is the level of serum hCG above which one should see an IUP by TVUS. On average, this is ~2500 IU/L for a TVUS (~6000 for Transabdominal US).

It is critical to note that there is considerable variation in hCG levels across pregnancies for each gestational age and discriminatory zone.

Serial hCGs that do not rise by 66% in 48 hours = abnormal pregnancy (ectopic or nonviable IUP) 

What about the heterotopic pregnancy?

This is a feared pathology that very rarely occurs. In fact, its estimated to occur in 1 in 30,000 pregnancies. Therefore, in a female that has a confirmed IUP with no assisted reproductive techniques being used (ART), no further workup for heterotopic pregnancy needs to occur.

The risk of heterotopic pregnancy in those using ART is 1.5 per 1000 pregnancies. Expect similar nonspecific symptoms of ectopic pregnancy. High index of rupture due to misdiagnosis.

In these patients, besides an IUP, signs of heterotopic pregnancy are complex adnexal mass or fluid. Often falsely labeled as a corpus luteum cyst. In stable patients, laparoscopy is the treatment of choice.

Treatment overview

Ectopic is confirmed, time to talk treatment. This discussion involves Ob/gyn obviously, but we briefly review it here for completeness sake and to educate the emergency provider.

All patients that are hemodynamically unstable and/or have tubal rupture = emergency surgery, always. That’s easy.

Who qualifies for Methotrexate (MTX) therapy? This form of medical therapy has been found to be quite beneficial at reducing surgical exposure and its associated complications. You do not need to know these for the test.

-hCG <5000 mIU/mL

-No fetal cardiac activity

-No heterotopic pregnancy,

-Not currently breastfeeding

-No lab abnormalities to MTX

-Patient is willing and able to follow up

If ANY of the above are not present, patients will require surgery.