Gastrointestinal Bleeding – Lower Gastrointestinal Tract
Guest: Dr. Todd Dantzler – Gastroenterology-Hepatology
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I am Dr. Linda Austin. I am talking today with Dr. Todd Dantzler who is Assistant Professor of Internal Medicine and a gastroenterologist at our Digestive Disease Center. Dr. Dantzler, let’s talk, in this podcast, about lower GI bleed, or bleeds from the large part of the intestine, at the end of the intestine. What are some of the causes of bleeding in that area?
Dr. Todd Dantzler: The most common causes of bleeding in the colon include hemorrhoids. Very commonly people bleed from internal or external hemorrhoids, diverticulosis, dilated veins, which are often called AVMs (arterio-venous malformations) or, certainly, cancer. While cancer is certainly the most feared of all of these causes, it is definitely not the most common cause. We have other causes, including inflammatory conditions, such as inflammatory bowel disease which includes Crohn’s disease as well as ulcerative colitis. We have other things, such as small veins or small arteries. One example is Dieulafoy’s lesion, which is too close to the surface. It becomes irritated and starts to spurt blood. It can be very difficult to find those. Other patients who have a history of constipation are at risk for what is called solitary rectal ulcer syndrome where you can have a large ulcer in the rectum which is also at risk for bleeding. Another cause would include ischemic colitis which is where you have lack of blood flow usually to the left side of the colon in what is called the watershed area because it has relatively decreased blood flow. So, those are the most common causes of lower GI bleeding.
Dr. Linda Austin: Now, I am sure you start the evaluation with a very good history and a physical, and then the dreaded colonoscopy. Is that right?
Dr. Todd Dantzler: Yes, ma’am. If anything, we are criticized for chomping at the bit for wanting to get to get to the colonoscopy but, of course, the physical exam is extremely important as well as labs, initially, to fully assess the patient. After those are appropriately done and it is decided that the colonoscopy is the best course of action, you have to proceed with a bowel preparation, which, these days, is usually done with any number of what is called polyethylene glycol solutions.
Dr. Linda Austin: Golightly?
Dr. Todd Dantzler: Golightly, exactly, although you end up not going so lightly. Our patients do not care for it very much. It is the safest bowel preparation that we have and if they do take it, the results actually turn out to be quite good in most cases.
Dr. Linda Austin: And having personally experienced it, I can say that the bowel prep, or taking the Golightly, is by far the most difficult part of the whole thing. Once you have swallowed the Golightly, it is all pretty easy after that point. The colonoscopy itself is really nothing. You sleep through the whole thing. That’s a piece of cake.
Dr. Todd Dantzler: Yes. I have actually had my own colonoscopy and I strongly feel that. My father actually had colon cancer when he was 45 which mandated that I have mine quite young and I am happy to say that everything went fine. I recommend it for everyone.
Dr. Linda Austin: Right. So, if you can just swallow that Golightly, you certainly are fine. What are some other examinations that you might do to evaluate the person with a lower GI bleed?
Dr. Todd Dantzler: In the event that we are unsuccessful with our colonoscopy which, unfortunately, does happen sometimes, there are several options. The first option would be, actually, to bring the patient back after another attempt at bowel preparation, or not if the bowel preparation was okay the first time around, and do another colonoscopy because sometimes it can be like finding a needle in a haystack. It can be very challenging. Just because one colonoscopy did not find the result does not mean you might not find it the second time around, particularly with such things as diverticular bleeding which can be very frustrating. Patients with known diverticulosis scattered throughout their entire colon come in with recurrent episodes of bleeding, and we have difficulty localizing that bleeding. Sometimes it takes more than one colonoscopy.
There are studies, including nuclear medicine studies, a nuclear red blood cell test, where they, basically, will tag the red blood cells with a nuclear agent which will then light up in the abdomen when scans are taken to help localize where the bleeding is actually coming from. If that is not helpful then the backup to that would be angiography which is basically where contrast agent is placed in the arteries and the same process of localization takes place. The good thing with the angiographers is if they actually find a bleed and localize it, they can then actually use various gelfoam agents and coils to occlude that artery that is bleeding and actually treat the patient completely.
Dr. Linda Austin: Wow.
Dr. Todd Dantzler: It is pretty amazing.
Dr. Linda Austin: That is very amazing. I understand there is a new technology where you actually swallow a pill that has a camera inside it?
Dr. Todd Dantzler: That is true. That is very true. It has most recently been applied to the colon. There is, in fact, a colon capsule which is out now. The first generation capsule is the small bowel capsule. We have had much success over the years looking at the small intestine for sources of hidden bleeding. The success, so far, with the colon capsule has been less so, though there have been up to 75 percent sensitivities reported in a couple of small studies that have been done in patients that have been prepped well, those patients do have to undergo a routine bowel preparation. They also have to have a preparation throughout the entire time that the capsule is being passed to promote continued passage of the capsule so that the images will be taken in time. It is technically challenging but it is being worked on as we speak and holds a lot of promise for the future.
Dr. Linda Austin: Dr. Dantzler, thank you so much.
Dr. Todd Dantzler: Thank you.
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