A 64 year old man presents with vomiting and colicky abdominal pain for 12 hours. His last bowel movement was 10 hours ago, although he usually voids his bowels between 2 to 3 times daily. No other symptoms are present. There is no history of abdominal trauma, while his medical and surgical histories are unremarkable. He only drinks socially, and has never smoked or used recreational drugs. A complete blood count, serum electrolyte assay, and renal profile are within normal parameters.
S. Amylase: 35 U/L (23-85) S. Lipase: 45 U/L (0-160)
The upright plain x-ray reveals multiple dilated loops of small bowel with air-fluid levels forming a stepladder pattern. There is no air under the diaphragm.
The contrast CT scan reveals multiple dilated loops of small bowel, with the point of obstruction in the distal ileum. Minimal pneumobilia is present.
You realize that colonoscopy is probably not indicated here.