Reproductive · Obstetrics
The facts most likely to be tested
The classic clinical triad for ectopic pregnancy consists of abdominal pain, vaginal bleeding, and amenorrhea.
The most common site for an ectopic pregnancy is the ampulla of the fallopian tube.
A transvaginal ultrasound is the diagnostic test of choice to confirm an intrauterine pregnancy or identify an adnexal mass.
A discriminatory zone of beta-hCG > 1,500–2,000 mIU/mL is the threshold at which an intrauterine pregnancy should be visible on ultrasound.
In a stable patient with an ectopic pregnancy, methotrexate is the first-line medical treatment if specific criteria are met.
Laparoscopic salpingostomy or salpingectomy is indicated for patients who are hemodynamically unstable or have contraindications to methotrexate.
Ruptured ectopic pregnancy presents with hemodynamic instability, peritoneal signs, and referred shoulder pain due to hemoperitoneum.
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A 26-year-old G1P0 woman presents to the emergency department with 3 days of lower abdominal pain and spotting. Her last menstrual period was 7 weeks ago, and she has a history of chlamydia infection. On physical exam, she has adnexal tenderness on the right side. Her beta-hCG is 2,200 mIU/mL, and a transvaginal ultrasound shows an empty uterus with a complex adnexal mass.
What is the most appropriate next step in management?
Laparoscopic surgery
The patient has a beta-hCG above the discriminatory zone with an empty uterus and an adnexal mass, confirming an ectopic pregnancy; because she is symptomatic and the pregnancy is likely advanced, surgical intervention is indicated.
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High yield triage
Etiology / Epidemiology
Most common site is the ampulla of the fallopian tube. Prior ectopic, PID, and tubal surgery are primary risk factors.
Clinical Manifestations
Classic triad: unilateral pelvic pain, vaginal bleeding, and amenorrhea. Cullen sign indicates intraperitoneal hemorrhage.
Diagnosis
Transvaginal ultrasound is the gold standard. Discriminatory zone of β-hCG > 1,500–2,000 mIU/mL confirms intrauterine pregnancy.
Treatment
Methotrexate is first-line for stable patients. Rupture or hemodynamic instability requires emergent surgical intervention.
Prognosis
Risk of recurrence is 10–15%. Rh-negative patients require RhoGAM to prevent isoimmunization.
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Epidemiology & Etiology
Incidence is highest in patients with a history of pelvic inflammatory disease or tubal ligation. Assisted reproductive technology and smoking also significantly increase risk. The vast majority occur in the fallopian tube, specifically the ampulla.
Pertinent Anatomy
The fallopian tube lacks a submucosa, allowing rapid invasion of the trophoblast into the muscularis. This anatomical limitation leads to early rupture and life-threatening hemoperitoneum.
Pathophysiology
Implantation occurs outside the endometrial cavity, preventing normal placental development. The growing embryo invades the tubal wall, causing local tissue destruction and vascular erosion. This process culminates in either tubal abortion or tubal rupture.
Clinical Manifestations
Patients present with the classic triad of abdominal pain, vaginal bleeding, and amenorrhea. Hemodynamic instability, shoulder tip pain (from diaphragmatic irritation), and Cullen sign (periumbilical ecchymosis) are signs of ruptured ectopic.
Diagnosis
Serial β-hCG levels should double every 48 hours in a viable pregnancy; failure to do so suggests ectopic. Transvaginal ultrasound is the gold standard for visualization. If β-hCG is above the discriminatory zone of 1,500–2,000 mIU/mL and the uterus is empty, ectopic is confirmed.
Treatment
Methotrexate is indicated for hemodynamically stable patients without evidence of rupture. Contraindications include fetal cardiac activity, β-hCG > 5,000, or renal/hepatic impairment. Surgical management via salpingostomy or salpingectomy is mandatory for unstable patients.
Prognosis
Post-treatment monitoring requires serial β-hCG until undetectable to ensure resolution. Future fertility is preserved in most cases, but patients face a 10–15% risk of recurrence. RhoGAM must be administered to all Rh-negative patients.
Differential Diagnosis
Appendicitis: localized RLQ pain with rebound tenderness
Ovarian torsion: sudden onset severe unilateral pain with adnexal mass
Spontaneous abortion: passage of tissue and open cervical os
Ruptured ovarian cyst: sudden onset pain often following intercourse
Pelvic inflammatory disease: bilateral pain with cervical motion tenderness