A 40-year-old female presents with colicky abdominal pain, vomiting, and obstipation for 2 days. An abdominal X-ray shows multiple dilated loops of small bowel arranged in a 'step-ladder' pattern with several air-fluid levels on erect views. These findings are most consistent with:

Explanation

The classic radiological signs of small bowel obstruction (SBO) on an abdominal X-ray include dilated loops of small bowel (typically >3 cm in diameter), often arranged in a 'step-ladder' pattern due to their stacked appearance, and multiple air-fluid levels on erect or decubitus views. The presence of valvulae conniventes (plicae circulares) that traverse the entire lumen helps distinguish small bowel from large bowel. Paralytic ileus typically shows diffuse bowel dilation (both small and large bowel) without a clear transition point and often fewer, less prominent air-fluid levels. Large bowel obstruction would show dilated colon proximal to the obstruction. Toxic megacolon is characterized by severe colonic dilation (typically >6 cm) with loss of haustral markings, often seen in inflammatory bowel disease.