A 32 yo F presents to the ED with acute onset of sharp RLQ abdominal pain. She reports a positive home pregnancy test. Serum hCG is 40,000 mIU/ml. Bedside US shows no evidence of IUP, but does show the following. What's the diagnosis? (scroll down for answer).

Answer: Ectopic Pregnancy

• Implantation of a fertilized ovum in a location other than the endometrial lining of the uterus
• Most common site is fallopian tube
• Suspect diagnosis in women of childbearing age with the following triad of symptoms: abdominal pain, amenorrhea, vaginal bleeding
• Risk factors include history of PID, prior ectopic, and previous tubal surgery
• An ectopic pregnancy may appear on ultrasound as the absence of an intrauterine pregnancy + any of the following: an adnexal ring structure/mass, an extra uterine embryo, or free fluid in the cul-de-sac
• Color doppler flow may show the classic "ring of fire" but absence of flow does not exclude an ectopic