VOTW: Interstitial Ectopic Pregnancy

This week’s VOTW is brought to you by… none other than our fantastic ED Medical Director Dr. Nubaha Elahi and Dr. Waters!

A 44 year old female G5P3 w/ hx of Essure procedure (a 99.3% effective method of contraception) presented to the ED with bilateral eye swelling x1 week. She also had a positive home pregnancy test and vaginal spotting. Without being mislead by the initial chief complaint on a busy fast-track shift the team performed a POCUS of the pelvis which showed...

Clip 1 shows a transabdominal view of the uterus with an empty gestational sac and a thick walled complex R adnexal cyst/mass. In the setting of a bHCG of 37000, this is concerning for an ectopic pregnancy!

Clip 2 shows a transvaginal view of the uterus with an eccentrically located gestational sac containing a fetal pole. Given the concern for interstitial ectopic, the team measured the endomyometrial mantle thickness (nice!) which was 1cm (still within normal range, however approaching the 8mm cutoff).

**The Essure procedure involved inserting metal coils in bilateral fallopian tubes to cause scarring. In 2018 it was taken off of the market because it was associated with many complications including ecotpic pregnancies. 

Endomyometrial mantle thickness measurement

Interstitial ectopic

An interstitial ectopic is a pregnancy implanted in the myometrium. It carries a higher rate of shock and hemoperitoneum and higher maternal mortality compared to the other ectopic pregnancies due to the highly vascular myometrium (1)

Think about interstitial ectopic pregnancy if you see an eccentrically placed gestational sac and measure the EMM.

Endomyometrial mantle (EMM) measurement

• EMM = thickness of the endometrium + myometrium

• Measure from outer edge of the gestational sac to outer edge of the uterus at the THINNEST portion that you see (image 1)

• EMM <8mm is concerning for an interstitial ectopic pregnancy

Back to the patient

OBGYN was consulted who admitted the patient for a laparoscopic hysterectomy. The final diagnosis was right interstitial ectopic pregnancy!

We’ve reviewed many ectopic pregnancy cases caught on POCUS recently- an example of a diagnosis where POCUS truly is saving lives! Keep up the great work!

References:

1. Rastogi R, Gl M, Rastogi N, Rastogi V. Interstitial ectopic pregnancy: A rare and difficult clinicosonographic diagnosis. J Hum Reprod Sci. 2008 Jul;1(2):81-2. doi: 10.4103/0974-1208.44116. PMID: 19562051; PMCID: PMC2700669.
   

POTD: Intubating the Pregnant Patient

Intubating a pregnant woman is intimidating because you have two patients to consider. Physiologic changes in pregnancy can affect intubation so it is important to plan ahead.

Both ventilation and acid-base status change during pregnancy. As progesterone rises, there is an increase in tidal volume, which results in maternal respiratory alkalosis. This creates a gas gradient to allow for the transfer of CO2 from the fetus to the mom. This maternal hypocarbia causes uteroplacental vasoconstriction, which can cause fetal hypoperfusion and hypoxia. This creates a very delicate acid-base balance that is exacerbated by increased fetal oxygen consumption and CO2 production in the third trimester. In addition, the diaphragm is pushed up by the gravid uterus reducing the mother's functional residual capacity by 10-25%. As a result of these factors, pregnant patients have a shorter safe apnea time and can desaturate quickly.

Progesterone also decreases the tone of the lower esophageal sphincter. Combined with increased intraabdominal pressure from the gravid uterus, pregnant patients are at higher risk for aspiration. For these reasons, you should be careful with bagging and consider intubating in a semi-upright position. This position also has the benefit of taking some pressure off of the patient's chest and IVC.

Anticipate a difficult airway in pregnant patients. Failed intubation is 8x more likely than in the general population. Human placental growth hormone secreted in pregnancy increases blood flow to the upper airways. This results in edema and hyperemia of the airway, causing it to be smaller and more friable. For this reason, you should prepare a smaller caliber ETT. Rocuronium and succinylcholine have been studied with similar efficacy. Induction agents therefore depend on patient specific factors.

TLDR: 1. preoxygenate well due to shorter safe apnea time. 2. Consider a smaller ETT for a narrower and more friable airway. 3. Limit aspiration risks by decreasing bagging if possible 4. consider intubating patients in a semi-upright position.

Thanks for reading! 

Ariella

References: 

https://rebelem.com/respiratory-failure-and-airway-management-in-the-pregnant-patient/

https://www.nuemblog.com/blog/intubating-the-pregnant-patient

https://www.uptodate.com/contents/airway-management-for-the-pregnant-patient

Medical Abortions & Misoprostol Toxicity

Medical abortions can be done until 11 weeks of pregnancy and are 98% successful in terminating a pregnancy. They are popular because they are relatively safe and easy to administer. As of 2021, patients can get these medications via mail or pharmacy. 

Contraindications for medical abortions include ectopic pregnancies, pregnancy > 11 weeks, adrenal insufficiency, renal failure, liver failure, cardiac disease, and coagulopathy. 

Medical abortions are typically performed using Mifepristone and Misoprostol. Mifepristone blocks progesterone, preventing the pregnancy from progressing. Misoprostol, a synthetic prostaglandin E1, induces uterine cramping to help expel the pregnancy (think: misoprostol, like prostaglandin). Misoprostol should be taken 24-48 hours after mifepristone and patients should expect to have some bleeding but it should not exceed 2 pads/hr for 2 consecutive hours (think: rule of 2s). Patients are encouraged to take a repeat pregnancy test at 4 weeks or get an US to confirm termination after taking these medications.  

• Mifepristone dose: 200 mg PO

• Misoprostol dose: 800 mcg x1-2 buccally or transvaginally. 

  • If given buccally, the patient will place two 200 mcg pills in each cheek and let them dissolve.

Given the stigma and laws prohibiting safe abortions, many people are now seeking alternative means for abortions, such as medications they find on the internet. Some medications marketed as misoprostol are not regulated and contain other dangerous substances. 

Misoprostol toxicity is very rare, however, due to more limited access to these medications people are at increased risk for harmful side effects. Normal doses of misoprostol in safe abortions are 200-1000 mcg depending on the route. This may cause a slight fever, chills, cramping, nausea, vomiting, or diarrhea, but symptoms typically improve quickly. Toxic doses are in the 3-8 mg range; these patients may have severe GI issues, high fever, chills, severe myalgias with rhabdo, bradycardia, hypoxia, AMS, and hypotension. Doses as high as 12 mg may result in multisystem organ failure and death. Symptoms develop very quickly after ingestion as it is completely absorbed from the stomach in 90 mins. Treatment involves removing any tablets from the vaginal canal, rectum, maybe stomach, and supportive care/symptomatic management until symptoms resolve (usually 12 hours). 

Thanks for reading! 

Ariella

Resources:

https://www.who.int/news-room/fact-sheets/detail/abortion

https://www.emrap.org/episode/emrap2022july1/postabortion

https://www.uptodate.com/contents/first-trimester-pregnancy-termination-medication-abortion?search=medical%20abortion&source=search_result&selectedTitle=1~73&usage_type=default&display_rank=1

https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-022-01889-6

Graber, D. J., & Meier, K. H. (1991). Acute misoprostol toxicity. Annals of emergency medicine, 20(5), 549-551.

Henriques, A., Lourenço, A. V., Ribeirinho, A., Ferreira, H., & Graça, L. M. (2007). Maternal death related to misoprostol overdose. Obstetrics & Gynecology, 109(2), 489-490.