Tricyclic antidepressant overdose — ABEM Board MCQ

Correct answer: B — CT abdomen and pelvis with IV contrast

This presentation is classic for acute small-bowel obstruction: abdominal pain, vomiting, distention, obstipation, tachycardia, and prior laparotomy scars suggesting adhesive obstruction. In current US practice, the most appropriate initial imaging study is CT abdomen and pelvis with IV contrast. CT confirms obstruction, identifies the transition point and likely cause, and evaluates complications that change management, including closed-loop obstruction, strangulation/ischemia, perforation, and need for urgent surgery. Plain abdominal radiographs may show dilated loops or air-fluid levels but are not definitive and cannot reliably identify the cause or complications. RUQ ultrasound evaluates biliary disease, barium swallow evaluates the esophagus/upper GI tract and is inappropriate in acute obstruction, and nuclear medicine bleeding scan is for active GI bleeding.

Reference: American College of Radiology (ACR) Appropriateness Criteria®: Suspected Small-Bowel Obstruction, current online criteria; Variant 1 acute suspected SBO lists CT abdomen and pelvis with IV contrast as Usually Appropriate. https://acsearch.acr.org/docs/69476/Narrative/