A 58-year-old man presents with acute onset colicky abdominal pain, nausea, and vomiting. On examination, the structure marked **A** in the diagram is noted, along with visible peristaltic waves and high-pitched tinkling bowel sounds. His abdomen is tender but soft, with no signs of peritonitis. Erect abdominal X-ray shows dilated small bowel loops with air-fluid levels. He had undergone appendectomy 15 years ago. What is the most appropriate initial management?

Explanation

## Why "NPO, nasogastric decompression, IV fluids, and trial of conservative management for 24-72 hours" is right The marked abdominal distension (**A**) in the context of acute small bowel obstruction (SBO) with colicky pain, tinkling bowel sounds, and no peritonitis indicates mechanical obstruction without strangulation. According to Bailey & Love 28e, SBO due to adhesions (most common cause, 60-70% post-surgical) WITHOUT signs of strangulation (no constant pain, no peritonitis, no rising lactate) should be managed conservatively initially with NPO status, nasogastric decompression, IV fluid resuscitation, and electrolyte correction. Many adhesive SBOs resolve spontaneously within 24-72 hours with this regimen. Surgery is reserved for signs of strangulation, peritonitis, complete obstruction not resolving, or virgin abdomen. ## Why each distractor is wrong - **Immediate surgical exploration for adhesiolysis**: While adhesions are the likely cause, immediate surgery is not indicated in uncomplicated mechanical SBO without signs of strangulation or peritonitis. Premature surgery increases morbidity and mortality; conservative management resolves 60-80% of adhesive SBOs. - **Endoscopic decompression with flatus tube placement**: This is the first-line approach for sigmoid volvulus, not small bowel obstruction. Rigid sigmoidoscopy is not applicable to proximal small bowel pathology. - **Gastrografin challenge followed by immediate laparotomy if not resolved**: While gastrografin can be used diagnostically and therapeutically in SBO, immediate laparotomy is not the next step if gastrografin fails to resolve the obstruction; further imaging and assessment for strangulation signs would be needed first. **High-Yield:** Adhesive SBO without strangulation → conservative management (NG decompression + fluids) for 24-72 hours; surgery only if signs of strangulation, peritonitis, or failed conservative trial. [cite: Bailey & Love 28e — Intestinal Obstruction: Management of Small Bowel Obstruction]