00:00
So let's move on to large bowel obstruction.
00:04
This is usually caused by a mechanical obstruction of the large bowel
and the cecum is usually, the part of the bowel that dilates the most.
00:12
The small bowel is often not dilated unless the obstruction is so severe
that it makes the ileocecal valve incompetent.
00:19
In a large bowel obstruction, you don’t want to administer oral barium
because it could become impacted within the bowel as water is absorbed from it.
00:29
So you wanna start off by doing a plain film and if you suspect a large bowel obstruction
then don't administer the oral contrast.
00:36
So let's move on to volvulus.
00:40
A volvulus is essentially a closed loop obstruction involving the large bowel.
00:44
It's most commonly seen in the cecal area and then it's followed by the sigmoid area.
00:50
Sigmoid volvulus tends to produce a characterized "coffee bean" shape appearance on radiographs.
00:55
With the cecal volvulus, you'll actually see a very dilated cecum that often rotates to the left upper abdomen.
01:03
On this film, you can see what appears to be a very dilated cecum.
01:07
It remains within the pelvis in this patient.
01:10
The small bowel will become dilated with volvulus
and as with the small bowel volvulus there's a very high risk of strangulation.
01:18
So let's take a look at this film, you can see the green line,
showing you a very dilated loop of large bowel, so what is this represent?
This is actually an example of a Sigmoid Volvulus
and you can see, this is the characteristic coffee bean shape that you would expect.
01:37
This is a surgical specimen demonstrating the same thing, a sigmoid volvulus.
01:43
So a colonoscopy is used to reduce the volvulus most often.
01:47
Occasionally, you can use a contract enema,
however you have to be careful because when you reduce the volvulus there is a high risk of perforation.
01:55
So what are other secondary science of volvulus.
02:00
You can see the whirl sign which is swirling of the mesentery
and that could be seen with both large volvulus and small bowel closed loop obstruction.
02:09
You can also see what's called the beak sign which is tapering the colon to the point of obstruction.
02:13
So let's take a look at these images, this is an axial CT image in a patient
that has a closed loop obstruction and here you can see what's called the beak sign.
02:24
So you can see tapering in to the colon, producing the appearance of the beak.
02:28
And then on the coronal image, keep your eye on this area right here as I scroll through.
02:33
You can see what looks like a swirling of this mesentery and this is another secondary sign of volvulus.
02:40
So Ogilvie Syndrome is actually massive dilatation of the colon without mechanical obstruction.
02:49
So as you recall, normal large bowel obstruction is often due to a mechanical obstruction.
02:54
This is one of the causes of a non-mechanical obstruction than can cause dilatation of the colon.
02:59
Usually this is due to anticholinergics which result in loss of peristalsis, trauma especially retroperitoneal.
03:06
Serious infection and cardiac disease.
03:09
So let’s go back to this case that we saw at the very beginning.
03:12
This is our 25 year old female that presents with right lower abdominal pain.
03:16
What do you see on this film?
So we see multiple loops of large bowel that contain air and that’s normal.
03:30
But how about right here? What is that represent?
So this is a prominent loop of air-filled small bowel
that seen in the left upper abdomen and this is consistent with the focal ileus.
03:50
As you can see here, it has that stacked coin appearance that we talked about.
03:54
So what's the next step? How do you figure out what's going on? Why does this patient have a focal ileus?
So you want to obtain of CT of the abdomen and pelvis with contrast to take a look for any kind of causes.
04:07
Remember there are multiple different causes of the small bowel focal ileus.
04:12
So let's take a look at this axial contrast enhanced CT scan.
04:17
And if you look right here, you actually have a very thick walled appendix with periappendiceal fat stranding.
04:28
Let's take a closer look. So this portion right here is all appendix.
04:32
Normally appendix should have a little bit air or a little bit of contrast within it
but you actually don't see the lumen at all because the wall is so thick
and if you look around it, let's take a look at normal mesentery so this area right here is normal mesentery.
04:47
Surrounding the appendix, the mesentery has a more grayish appearance and this is because of surrounding inflammation.
04:55
So this patient has an acute appendicitis that caused her focal ileus.
04:59
So we've gone over a multiple different causes, of large and small bowel obstruction.
05:04
Again this is a very common finding that you wanna look out for when you see a patient coming in with abdominal pain.