Clues Pointing TO This Diagnosis

Positive pregnancy test — confirmed but intrauterine pregnancy not yet seen
Sharp unilateral pelvic pain — left or right side
Vaginal bleeding — not typical period — lighter or darker
History of pelvic inflammatory disease — prior tubal damage
Beta-hCG rising slower than expected — not doubling appropriately every 48 hours
Empty uterus on transvaginal ultrasound — no intrauterine gestational sac
Adnexal mass or free fluid on ultrasound
Hemodynamic instability — shoulder tip pain — from hemoperitoneum
Responds to surgery — salpingectomy — or methotrexate if stable

Why It's NOT the Similar Diseases

NOT normal early pregnancy with threatened miscarriage — threatened miscarriage has bleeding but the gestational sac is IN the uterus on ultrasound. Ectopic has empty uterus — adnexal mass — rising but inappropriately slow beta-hCG.
NOT ovarian cyst rupture — ovarian cyst rupture causes sudden pelvic pain but pregnancy test is NEGATIVE. Angela has a positive test — ectopic must be the working diagnosis.
NOT appendicitis — appendicitis causes right lower quadrant pain — fever — elevated WBC — nausea — no positive pregnancy test typically — ultrasound shows appendix not adnexal pathology.
NOT pelvic inflammatory disease — PID causes bilateral pelvic pain — fever — cervical motion tenderness — discharge. Angela's pregnancy test is positive — PID does not cause a positive test.
NOT intrauterine pregnancy with corpus luteum cyst — corpus luteum cysts are normal in early pregnancy and can cause mild pelvic discomfort — but gestational sac is visible IN the uterus — no hemodynamic instability.

Differential Diagnosis List

Threatened miscarriage — ruled out by empty uterus on ultrasound — adnexal mass
Ovarian cyst rupture — ruled out by positive pregnancy test and rising beta-hCG
Appendicitis — ruled out by positive pregnancy test — adnexal location — ultrasound
Pelvic inflammatory disease — ruled out by positive pregnancy test — unilateral pain
Corpus luteum cyst — ruled out by inappropriately rising beta-hCG — empty uterus — adnexal mass

Key Distinguishing Test

Transvaginal ultrasound — gold standard — empty uterus with positive pregnancy test is ectopic until proven otherwise. Beta-hCG — failing to double every 48 hours suggests abnormal pregnancy. Beta-hCG discriminatory zone — above 1500 to 2000 mIU/mL — gestational sac should be visible in uterus — if not visible at this level ectopic is presumed.

Board Note

📝 THE ECTOPIC TRIAD: Amenorrhea — vaginal bleeding — unilateral pelvic pain. Risk factors — prior PID — prior ectopic — prior tubal surgery — IUD — smoking — assisted reproduction. Management — stable with small ectopic under 3.5 to 4 cm — methotrexate. Unstable or large ectopic — emergency surgery. Rh negative patients need Rho-D immune globulin. Never do bimanual exam in a hemodynamically unstable patient with suspected ectopic.

“Angela’s Story”