0:01

So this is a 90-year-old female, had weakness,

0:03

altered mental status, and had fallen, and

0:06

so they wanted to get a CT scan to evaluate

0:08

for any injuries, and got a non-contrast CTA.

0:12

We scroll through these images, there's a

0:14

couple of findings we know right off the bat.

0:16

Presence of pneumobilia, and a very distended

0:20

stomach, and as we scroll more inferiorly, we see

0:24

that not only the stomach is distended, but there

0:26

are numerous loops of small bowel that are distended.

0:29

There are also loops of small bowel that

0:30

are under-distended, so we have to be

0:32

worried about a small bowel obstruction.

0:34

Next step is to look for the transition,

0:39

and as we evaluate the transition, we see that

0:41

there is actually a peripherally calcified

0:43

mass that's residing in the small bowel itself.

0:47

And beyond that area where that mass resides,

0:51

the bowel is relatively under-distended.

0:55

If we look at this on the coronal, we can again

0:56

see the, uh, the stomach distension, the bowel

0:59

distension, all the way leading up to this peripherally

1:02

calcified mass in the small bowel, and then beyond

1:06

it, we see under-distended loops of small bowel.

1:10

Nobilius, of course, is again seen on these images.

1:13

And so these findings are

1:14

characteristic of gallstone ileus.

1:17

Now we call it an ileus, but it's actually a

1:20

form of mechanical obstruction, albeit a very

1:23

uncommon and rare form of mechanical obstruction.

1:26

Which occurs secondary to a gallstone which

1:28

is passed through a fistulous tract that forms

1:32

from the gallbladder to a portion of the bowel.

1:36

Often these patients have a history of

1:38

chronic cholecystitis, that sort of prolonged

1:41

repeated inflammation promotes sort of

1:43

this presence of this tract through which

1:45

gallstones can escape into the bowel.

1:48

It's more commonly seen in older females, and the

1:51

stones gallstones tend to impact at areas of relative

1:55

lumen narrowing in the bowel, such as the

1:57

ligament of Treitz, ileocecal valve, sigmoid colon.

2:01

In this instance, it's just trapped somewhere

2:03

in the bowel, none of those locations.

2:06

And, uh, in fact, there's also something

2:09

called a regular triad that's been described.

2:12

For gallstone ileus, it's a finding that's

2:13

been described on, uh, abdominal radiographs.

2:17

So it may not be as relevant when, uh,

2:19

in the era of, uh, CT scans that we

2:21

have now, but that finding essentially.

2:23

The triad really is the presence of pneumobilia,

2:26

which you can see in this instance, the presence

2:28

of a bowel obstruction here, you can see distended

2:30

stomach, multiple distended loops of small bowel, under

2:32

distended, uh, remaining loops of bowel, so there's

2:34

a bowel obstruction, and the presence of a gallstone,

2:38

which we can see right over here faintly, but we

2:40

can see it knowing where it is, uh, on the CT scan.

2:43

So those trio findings are known as Riegler's triad,

2:47

a finding of gallstone ileus on abdominal radiographs.