Bowel Obstruction and Ileus: Large Bowel Obstruction & Ogilvie Syndrome

by Hetal Verma, MD

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    00:01 So let's move on to large bowel obstruction.

    00:04 This is usually cause 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 couldn't become impacted within the bowel as water is absorbed from it.

    00:29 So you wanna start of by doing a plain film and if you suspect the large bowel obstruction, then don't administer the oral contrast.

    00:36 So let's move one to volvulus a volvulus is essentially a closed loop obstruction involving the large bowel. It's most commonly seen in the caecal area and then it's followed by the sigmoid area.

    00:50 Sigmoid volvulus tends to produce a characteristic coffee bean shape appearance on radiographs.

    00:56 With the caecal volvulus you actually see a very dilated cecum that often rotates to the left upper abdomen.

    01:03 On this film you can see what it appears to be a very dilated cecum.

    01:06 It remains within the pelvis in this patient.

    01:10 The small bowel will become dilated with the 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 are very dilated loop of large bowel.

    01:27 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. 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 contrast enema.

    01:50 However, you have to be careful because when you reduce the volvulus there is a high risk of perforation.

    01:56 So what are other secondary signs of volvulus? You can see the whirl sign which is swirling of the mesentery and that can 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 of the colon to the point of obstruction.

    02:14 So let's take a look at these images.

    02:16 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 of 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. 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 that can cause dilatation of the colon.

    02:59 Usually this is due to anticholinergics which result in loss of peristalsis of the colon.

    03:05 So let's go back to this case that we saw at the very beginning.

    03:09 This is our 25-year-old female, that presents with the right lower abdominal pain.

    03:13 What do you see on this film? So we see multiple loops of large bowel that contain air and that's normal, but how about right here? What is that represent? So this is a prominent loop of airfield small bowel that seen in the left upper abdomen and this is consistent with the focal ileus.

    03:46 As you can see here, it has that stacked coin appearance that we talked about.

    03:51 So what's the next step? How do you figure out what's going on? Why is this patient have a focal ileus? So you wanna obtain a CT of the abdomen and pelvis with contrast to take a look for any kind of causes.

    04:05 Remember there are multiple different causes of the small bowel focal ileus.

    04:09 So let?s take a look at this axial contrast enhanced CT scan and if you looked right here, you actually have a very thick walled appendix with periappendiceal fat stranding.

    04:25 Let's take a closer look. So this portion right here is all appendix.

    04:29 Normally, appendix should have a little bit of air or a little bit of contrast within it.

    04:34 But you actually don?t see the lumen at all because the wall is so thick and if you looked around it, let's take a look at normal mesentery.

    04:42 So this area right here is normal mesentery, surrounding the appendix, the mesentery has a more grayish appearance and this is because of surrounding inflammation.

    04:51 So this patient has an acute appendicitis that cause for focal ileus.

    04:56 So we've gone over multiple different causes of large and small bowel obstruction.

    05:01 Again, this is a very common finding that you wanna look out for when you see a patient coming in with abdominal pain.

    About the Lecture

    The lecture Bowel Obstruction and Ileus: Large Bowel Obstruction & Ogilvie Syndrome by Hetal Verma, MD is from the course Abdominal Radiology. It contains the following chapters:

    • Large Bowel Obstruction
    • Ogilvie Syndrome

    Included Quiz Questions

    1. Massive diffuse dilatation of the colon.
    2. Swirling of the mesentery.
    3. Beak sign.
    4. "Coffee bean" dilatation of the colon.
    5. Dilated cecum.
    1. …it could become impacted as water is absorbed from it.
    2. …it could cause a bowel hernia.
    3. …it could cause strangulation.
    4. …bowel wall tends to retain the barium for months.
    5. …it could give a false diagnosis.
    1. Functional obstruction is the most common large bowel obstruction.
    2. Cecum often dilates the most.
    3. A volvulus is a closed loop obstruction involving the large bowel.
    4. In a caecal volvulus, the dilated cecum often rotates to the left upper abdomen.
    5. There is a high risk of strangulation.
    1. Whirl sign
    2. Beak sign
    3. Coffee bean sign
    4. Corkscrew sign
    5. Rigler’s sign
    1. Massive dilatation of the colon without mechanical obstruction.
    2. Massive dilatation of the cecum with a normal colon.
    3. Functional dilatation of the rectum.
    4. Mechanical obstruction of the colon with dilatation.
    5. Absent peristalsis in the ileum leading to dilatation of the colon.

    Author of lecture Bowel Obstruction and Ileus: Large Bowel Obstruction & Ogilvie Syndrome

     Hetal Verma, MD

    Hetal Verma, MD

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