Bowel perforation

What it means

A perforation is a full-thickness tear or hole in the wall of the stomach or intestine. Once that happens, air, digestive fluid, and sometimes stool or food contents that are normally sealed inside the gut can spill into the abdominal cavity. This is different from a simple ulcer or inflamed patch, which stays within the wall — a perforation goes all the way through, and what leaks out irritates and can infect everything it touches.

Why it appears on a CT or MRI report

Radiologists rarely see the hole itself; instead they look for its footprints. The most telling sign is free air (pneumoperitoneum) — pockets of gas outside the bowel where no gas should be, often seen tucked under the diaphragm or scattered between loops of bowel. Free fluid, a focal defect in the bowel wall, thickening at one segment, and streaky inflammation in the surrounding fat (fat stranding) often accompany it. The report may name a likely site — stomach, duodenum, small bowel, colon, or appendix — based on where these signs cluster, and will typically flag the finding as urgent.

What it usually means

Perforation has several common causes: a peptic ulcer that has eaten through the stomach or duodenal wall, a burst appendix or diverticulum, a tumour that has weakened the wall, trauma, or, less often, a complication of a swallowed foreign object or recent surgery or endoscopy. Whatever the cause, a hole in the gut is a surgical emergency. Leaking gut contents cause chemical and then bacterial peritonitis — inflammation and infection of the abdominal lining — which can progress quickly to sepsis if untreated. This is one of the few imaging findings that typically triggers an immediate call to a surgical team rather than a routine referral.

When to follow up

If you're reading this term because it appears on your own report, you are almost certainly already in an emergency department or hospital, and the care team will already be moving quickly — surgery is the usual treatment, sometimes alongside antibiotics and fluids. If you somehow encounter this term outside that setting, severe or worsening abdominal pain, a rigid or tender belly, fever, vomiting, or feeling suddenly very unwell are reasons to go to an emergency department immediately rather than waiting for a scheduled appointment. This is not a finding to sit with.

A plain-language way to picture it

Think of the bowel as a hose carrying wastewater, sealed at every joint. A perforation is a split in that hose — once it opens, the wastewater doesn't stay contained anymore; it starts seeping into the surrounding space it was never meant to touch. On a scan, the tell-tale sign isn't the split itself but the puddle and the stray air bubbles it leaves behind, which is exactly what radiologists are trained to spot first.