Bowel obstruction

What it means

The intestines are a long, continuous tube that moves food from the stomach to the rectum. When something pinches or blocks that tube, whatever is upstream of the block has nowhere to go. The gut above the blockage stretches with trapped fluid and gas; the gut below it stays empty and collapsed. On a CT scan, that contrast between distended loops and collapsed loops is the signature radiologists look for.

Why it appears on a CT or MRI report

Reports usually specify whether the block is in the small or large bowel, where the transition point sits, and what is causing it when that can be seen. Common modifiers include partial versus complete, simple versus closed-loop, and any signs of compromised blood supply to the bowel wall. The radiologist may name a likely cause — adhesions from prior surgery, a hernia, a tumour, a twist (volvulus), or an inflamed pouch — because the cause changes how urgently and how surgically the team responds.

What it usually means

The most frequent cause in adults who have had prior surgery is scar-tissue bands (adhesions) that have pinched a loop of gut. Hernias are another common culprit, especially when a loop of intestine has slipped through a weak point in the abdominal wall. In older adults, a new blockage in the large bowel raises concern for a tumour. Twists, severe constipation, inflamed diverticula, and inflammatory bowel disease can all do it too. Severity ranges widely. A partial blockage may settle with bowel rest, fluids through a vein, and a tube to decompress the stomach. A complete blockage, or one with signs that the bowel wall is losing its blood supply, is treated as a surgical emergency because the bowel can perforate within hours.

When to follow up

This is almost always an in-hospital conversation, not an outpatient one. If you are reading the report at home, contact your doctor or an emergency department the same day. Severe cramping belly pain that comes in waves, vomiting (especially if it turns green or brown), a swollen tight belly, inability to pass gas or stool, and fever are red-flag symptoms that pair with this finding and need immediate attention. The earlier the team acts, the more likely the bowel itself can be saved without surgery.

A plain-language way to picture it

Picture a long garden hose with a kink halfway down. Water keeps flowing in from the tap, but it can't get past the kink, so the hose upstream balloons out and the section past the kink stays flat. Push hard enough and the hose either bursts or the kink finally lets go. The gut behaves the same way — and finding the kink quickly is what protects the rest of the hose.