A 35-year-old woman presents to the emergency department with severe abdominal pain and vaginal bleeding following a missed period of 8 weeks. On examination, she is hypotensive (BP 90/60 mmHg), tachycardic (HR 120/min), and in severe distress. Clinical suspicion is high for ruptured ectopic pregnancy with hemorrhagic shock. Which investigation is most appropriate to confirm the diagnosis and guide immediate management?

Explanation

## Investigation of Choice in Suspected Ruptured Ectopic Pregnancy ### Clinical Context This patient presents with the classic triad of hemorrhagic shock: hypotension, tachycardia, and severe pain with a history suggestive of ruptured ectopic pregnancy. The investigation must be rapid, non-invasive, and capable of detecting both the ectopic gestation and free fluid (blood) in the pelvis. ### Why Transvaginal Ultrasound is Correct **Key Point:** Transvaginal ultrasound (TVUS) is the gold standard investigation for suspected ruptured ectopic pregnancy in a hemodynamically unstable patient. 1. **Speed and bedside availability** — can be performed at the bedside without moving an unstable patient 2. **High sensitivity and specificity** — detects intrauterine pregnancy, adnexal mass, and free fluid (hemoperitoneum) with >95% accuracy 3. **No radiation or contrast** — safe in pregnancy and acute settings 4. **Guides immediate management** — confirms diagnosis and allows rapid decision for emergency surgery ### Comparison with Other Investigations | Investigation | Utility in Ruptured Ectopic | Limitations | |---|---|---| | **Transvaginal ultrasound** | Gold standard; rapid; detects free fluid | Operator-dependent; may miss small ruptures | | **Serum beta-hCG** | Confirms pregnancy; serial levels assess viability | Does NOT differentiate intrauterine from ectopic; cannot detect rupture | | **Diagnostic laparoscopy** | Definitive visualization; therapeutic | Invasive; requires anesthesia; delays treatment in unstable patient | | **CT abdomen/pelvis** | Excellent for hemoperitoneum; good sensitivity | Radiation; requires transport; slower than TVUS; overkill in acute setting | **High-Yield:** In a hemodynamically unstable patient with suspected ruptured ectopic pregnancy, do NOT wait for CT or labs — TVUS at the bedside is the fastest confirmatory test and allows immediate surgical intervention. ### Clinical Pearl Free fluid in the pouch of Douglas on TVUS in the context of a positive pregnancy test and no intrauterine gestational sac is pathognomonic for ruptured ectopic pregnancy. This finding mandates emergency laparotomy. ### Mnemonic for Shock Investigation Priority **FAST-TVUS** — **F**ocused **A**ssessment with **S**onography for **T**rauma (or in this case, hemorrhage) + **T**ransvaginal **U**ltrasound **S**can = rapid bedside diagnosis in unstable patients.