HPI: 34yo female presents with abdominal pain located in the RLQ. Found to have + pregnancy test on arrival with LMP approximately 1 month ago. No vaginal bleeding. HCG in 500s.

Imaging: Formal pelvic ultrasound reveals "cyst-like structure" in endometrium without a fetal pole. No adnexal masses. Normal ovarian blood flow. No significant free fluid.

Event: Patient has syncope in the ER.  

Bedside Ultrasound in the RUQ:

hat structures do you see?

What is abnormal about this ultrasound?

Bedside Ultrasound in the suprapubic view:

Where is the uterus?

Is there a gestational sac?

What is abnormal about this ultrasound?

Diagnosis: Ruptured ectopic pregnancy

Ultrasound Education:

A FAST exam is indicated in any clinical situation in which there is concern for intra-abdominal free fluid or hemorrhage. It is used most often in blunt and penetrating cardiac and abdominal trauma, but is also used when investigating ectopic pregnancy.  A moderate amount of free fluid in the abdomen is highly suggestive of an ectopic in the right clinical situation and a FAST exam can reduce the time to diagnosis and treatment of ectopic pregnancy.

This patient has a "pseudo-sac" which is a small collection of intrauterine fluid without presence of a yolk sac, fetal pole, or double-decidual sign (where the decidua lining the uterine cavity meets the decidua lining the gestational sac).  However early pregnancies can appear similar to a "pseudo-sac".

During the FAST exam, the patient lies supine, such that fluid will first accumulate in Morrison's pouch as seen on this ultrasound.  The 4 views of the FAST exam include:

1) RUQ (Morrison's pouch)

2) LUQ (Splenorenal recess)

3) Suprapubic area

4) Subxiphoid area (pericardium)

Additional resources: 

-Free fluid in Morison's pouch on bedside ultrasound predicts need for operative intervention in suspected ectopic pregnancy. https://www.ncbi.nlm.nih.gov/pubmed/17554008

-Use of a beta-hCG discriminatory zone with bedside pelvic ultrasonography https://www.ncbi.nlm.nih.gov/pubmed/21310509

-Accuracy of first-trimester ultrasound in diagnosis of intrauterine pregnancy prior to visualization of the yolk sac: a systematic review and meta-analysis https://www.ncbi.nlm.nih.gov/pubmed/25393076