Bowel Obstruction and Ileus: Large Bowel Obstruction & Ogilvie Syndrome

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.