Lower Gastrointestinal Bleeding
Management of Hemorrhage From the Intestine, Colon, Rectum, and Anus
Apr 18, 2008
Gastrointestinal bleeding is a diagnosis commonly managed by gastroenterologists. Given the length of the digestive tract, there are many causes for GI bleeding. It can be divided into upper GI bleeding and lower GI bleeding, the latter of which will be discussed here.
Causes
Lower GI bleeding originates in the GI tract from the ligament of Treitz where the duodenum, the first part of the small intestine, ends to the anus. Colon cancer is a common cause for lower GI bleeding. Another cause is diverticulosis, the presence of portions of the intestinal wall stretched into the shape of pockets (diverticuli) that are prone to bleeding. Bleeding from the anus may occur from hemorrhoids or trauma due to the passing of hardened stool. These causes do not necessarily represent a complete list of causes for lower GI bleeding.
Symptoms and Signs
The main symptom of lower GI bleeding is blood exiting the anus, either alone (bright red blood per rectum) or as red-stained stool (hematochezia). Stool that is tarry and dark (melena) typically points to upper GI bleeding. Otherwise, bleeding over time results in anemia, characterized by lower than normal blood hemoglobin and hematocrit with symptoms like weakness, fatigue, and fainting.
Evaluation and Treatment
One step that can be performed to evaluate lower GI bleeding is colonoscopy. This can only be done once the colon is cleared of stool, which is often achieved with large quantities of a special laxative (e.g., GoLytely). During the procedure, a gastroenterologist passes a tube with a camera (colonoscope) into the anus and advances it to examine the rectum and colon, looking for a bleeding site. Any active bleeding can be stopped at the site or sites of origin using thermal methods or chemical methods (e.g., epinephrine). The necessary tools, including biopsy instruments if necessary to take tissue samples, are brought to the site through the tube portion of the colonoscope.
Besides colonoscopy, the gastroenterologist may also perform upper endoscopy along with colonoscopy if there is the possibility of upper GI bleeding being the cause of bleeding from the anus. In some cases, the patient may undergo arteriography to visualize the blood vessels to the lower GI tract or a nuclear scan with tagging of red blood cells to detect the bleeding site.
The remainder of treatment addresses the underlying causes of the bleeding. For example, lower GI bleeding due to colon cancer requires surgery..
Upper GI Bleeding
For information on the causes, symptoms, signs, evaluation, and treatment of upper GI bleeding, click here.
References
- eMedicine - Gastrointestinal Bleeding, Lower
- eMedicine - Lower Gastrointestinal Bleeding: Surgical Perspective
