Blunt Abdominal Trauma
- Blunt abdominal trauma is the workhorse abdominal emergency: a car crash, a fall, a handlebar to the gut — and your job is to find which organ is leaking.
- The stable patient gets a contrast-enhanced CT of the abdomen and pelvis; CT is the referee that decides who goes to the OR, who goes to angio, and who just gets watched.
- Spleen, liver, and kidney are the usual victims. Hunt for solid-organ lacerations, free fluid, and the thing everyone fears most: a contrast blush (active bleeding).
- The unstable patient does not go to CT. They get a bedside ultrasound and, often, a trip straight to the operating room.
- "No free fluid" is reassuring, not a guarantee — bowel and pancreatic injuries love to hide.
Someone arrives after a high-speed crash, awake but pale, with a seatbelt bruise blooming across the belly. Something inside might be bleeding, and the abdomen is annoyingly good at hiding that — it's a big, soft, opaque container that can quietly swallow a couple of liters of blood before anyone notices. Your imaging is the flashlight you shine into that container. This page is about how to shine it.
First question: is the patient stable?
Before anyone touches a scanner, the whole pathway forks on one word: stable or not.
A hemodynamically unstable patient — crashing blood pressure, racing heart — does not belong in the CT scanner. CT is a wonderful machine but a terrible place to resuscitate someone; it's a narrow tube down the hall, away from the OR. For these patients the answer is a bedside ultrasound called the FAST exam (Focused Assessment with Sonography in Trauma), which asks one blunt question: is there free blood in the belly? If yes, and the patient is unstable, that's frequently a one-way ticket to the operating room — no CT required.
The stable patient is the one CT was built for. That's where most of this page lives.
CT is for stable patients. Putting a crashing trauma patient in the scanner to "get more detail" can cost the minutes that kill them. Stability decides the pathway, not curiosity.
The scan you actually order
For stable blunt abdominal trauma, the standard study is a contrast-enhanced CT of the abdomen and pelvis, almost always rolled into a larger polytrauma CT that also covers head, neck, and chest. The contrast is the whole point: intravenous iodinated dye lights up the blood vessels and the solid organs, so a torn spleen shows up as a dark cleft in an otherwise bright organ, and a leak shows up as dye where dye shouldn't be.
Most centers run the abdomen in the portal venous phase (a delay that fills the organs nicely), and add an arterial and/or delayed phase when they suspect active bleeding and want to know whether it's arterial spray or a slower venous ooze.
The systematic read
When the images load, resist the urge to stare only at the scary organ. Trauma rewards a checklist. I read it roughly like this:
- Solid organs — spleen, liver, kidneys, pancreas. Look for lacerations (dark clefts), hematomas, and devascularized (non-enhancing) chunks.
- Free fluid — in trauma, fluid in the wrong places usually means blood. Check the spaces around the liver and spleen and the pelvis, where blood pools with gravity.
- Active bleeding (the contrast blush) — a focal blob of contrast outside a vessel that pools or grows on later phases. This is the single most important finding.
- Hollow organs & mesentery — bowel wall thickening, free air, mesenteric stranding or fluid between bowel loops. Subtle, sneaky, and dangerous.
- Bones & retroperitoneum — spine, pelvis, and the deep back compartments.
| Finding | What it looks like | Why it matters |
|---|---|---|
| Solid-organ laceration | Dark linear cleft in a bright organ | Grades the injury; guides watch-vs-treat |
| Free fluid | Low-density fluid in dependent spaces | In trauma, usually hemoperitoneum |
| Contrast blush | Focal contrast outside a vessel, pools/grows | Active bleeding — call now |
| Bowel injury | Wall thickening, free air, interloop fluid | Easy to miss, needs surgery |
The blush is the alarm bell
Of everything on that list, the active contrast extravasation ("blush") is the finding that changes the room's energy. Think of a garden hose with a pinhole: on the arterial phase you see a little jet of dye escaping, and on the delayed phase that puddle has spread out and faded at the edges — proof it came from the bloodstream and is still flowing. That patient may need the interventional radiologist to plug the leak with renal- or splenic-style embolization, or the surgeon.
A contrast blush that pools and spreads on delayed images = active hemorrhage. It is the finding you phone the trauma team about before you've finished scrolling.
How bad is it? Grading and where it leads
Solid-organ injuries get formally graded (the widely used AAST organ injury scales), and the management philosophy has shifted hard toward non-operative management — many splenic and liver injuries are now watched, not cut, as long as the patient stays stable. The exact grading thresholds live on the dedicated solid organ injury grading page; here, just hold onto the principle: the CT grade and the patient's vital signs together decide the plan, not either one alone.
Traps that bite
"No free fluid" does not mean "no injury." Bowel and pancreatic injuries can be present with little or no early fluid, and they get worse fast. Trust the mesenteric clues — interloop fluid, fat stranding, wall thickening — even when the spleen and liver look pristine.
Beware the bladder. Free fluid in the pelvis is usually blood, but in a patient with a pelvic fracture and hematuria it can be urine from a ruptured bladder — a different problem needing a CT cystogram, not a laparotomy.
If you remember only one thing, make it the fork in the road: stability first, then CT for the stable patient, and the contrast blush is the alarm. Everything else — the grades, the phases, the checklist — hangs off that frame.