A 28-year-old woman presents with a 24-hour history of periumbilical pain that migrated to the right lower quadrant, associated with nausea and mild fever (37.5°C). On examination, she has right lower quadrant tenderness and mild rebound tenderness. Her leukocyte count is 11,200/μL with a left shift. Her Alvarado score is calculated as 5. The structure marked **B** in the diagram indicates the management approach for this score range. Which of the following is the most appropriate next step in her management?

Explanation

## Why "Perform imaging (ultrasound or CT) to further evaluate before deciding on surgery" is right An Alvarado score of 4–6 falls in the **equivocal range**, representing an intermediate probability (~20–50%) of acute appendicitis. According to the Bailey & Love classification and CODA trial evidence, scores in this range mandate **imaging for further risk stratification** before committing to surgery. In this case, the patient is a non-pregnant adult; either ultrasound (sensitivity ~85%, specificity ~95%) or CT abdomen-pelvis with IV contrast (sensitivity >95%, specificity >95%) is appropriate. This imaging-guided approach reduces unnecessary appendicectomies while ensuring timely surgical intervention if imaging confirms appendicitis. ## Why each distractor is wrong - **Proceed directly to laparoscopic appendicectomy without further imaging**: This approach is reserved for **Alvarado scores ≥7** (high probability, 80–100% appendicitis), particularly in classic male presentations. A score of 5 is equivocal and does not justify immediate surgery without imaging confirmation. - **Observe with serial clinical examination and discharge with return precautions if symptoms resolve**: This conservative approach applies to **Alvarado scores 1–3** (low probability, ~5% appendicitis). A score of 5 carries significantly higher risk and requires imaging, not observation alone. - **Administer intravenous antibiotics and plan for interval appendicectomy after 6–8 weeks**: This strategy is reserved for **perforated appendicitis with abscess formation**, not uncomplicated equivocal presentations. The CODA trial supports antibiotic monotherapy for uncomplicated appendicitis without perforation, but only after imaging has confirmed the diagnosis and ruled out complications. **High-Yield:** Alvarado score 4–6 = **imaging mandatory**; score 1–3 = observe; score ≥7 = surgery (±imaging based on clinical context). [cite: Bailey & Love 28e; CODA Trial NEJM 2020]