© Veterinary Medical Associates 2011

Your Pet: Rectal Bleeding

It sounds to me like Bruno is a pampered companion.  He spends his days outside patrolling his acre of property in the Sierra foothills, that is of course unless there are weather issues in which case he retreats inside the house.  His nights are spent inside and he sleeps in the same bed with his caretakers Marcie and Clay, which, since he is a ninety pound German Shepard, must be quite the sight.  Bruno is six years old. Recently, Marcie reports noticing blood coming from somewhere on Bruno’s backside.  She has also seen blood in his stool and is suspicious the blood is actually coming from inside.  She is very worried realizing that in humans, blood from the rectum can be a sign of colon cancer.  Indeed colon cancer in people can cause bleeding which can show in the stool.  Fortunately, colon cancer is very rare in dogs and hopefully is not the cause of Bruno’s bleeding.  What I will do here is run through a few things that might cause the blood that Marcie has reported but realize as I know many of you who regularly read my column do, Bruno needs to visit his veterinarian to get to the bottom of his bleeding problem, no pun intended. If the blood is coming from inside Bruno’s rectum, then the source is likely the colon or large intestine.  The most common cause for this is colitis.  The colon is part of the digestive tract, toward the end.  It is the place where stool is formed.  It does not do much digesting but instead, primarily functions to resorb water from the stool.  When it is “upset”, the stool can become looser sometimes appearing like it has a jelly like substance upon it.  This is mucous.  If it gets really upset, it can bleed.  The key is what might be causing the colitis.  These most common causes are usually not primary colitis but instead the problem lies further up the digestive tract in the small intestine.  If the small intestine is not digesting food properly, it can pass material to the colon in a less than digested form.  This allows the bacteria which live normally in the colon to ferment this material which then irritates the colon wall causing colitis which can lead to the blood.  The most common cause of this type of colitis is ingestion of inappropriate food such as meat scraps and other high fat items.  I would be willing to wager that Bruno has taught his caretakers to feed him other than ideal foods basing that wager on his sleeping arrangements.  There are other possible causes.  As mentioned, though rare, masses in the colon can cause blood in the stool.  Trauma to the rectum or anal area can do so also.  Anal gland disease, usually infection and abscessing can cause bleeding that could possible end up on the stool.  This can also be seen by simply raising the tail and looking just below the anus on either side.  Dogs with this problem are usually quite uncomfortable.  A tumor of the anal gland or of the tissue around the anus can also bleed.  I am not betting on any of these as the cause for Bruno’s problem.  If one of them was the culprit I would have expected Marcie to report blood on the bed sheets as the bleeding can occur and leak from the rectum without defecation.  Another possible cause for the blood in Bruno’s problem is a disease that is prevalent in German Shepards.  It is the development of what are called perianal fistulas.  These are tracts that lead from the rectum outside around the anus.  They are very uncomfortable and require very diligent treatment to overcome.  I do not think Bruno has these primarily because there was not mention on discomfort and again, no blood on the sheets. In fact, I believe Bruno has secondary colitis as I mentioned above and the good news there is that with some proper treatment and a more disciplined diet, he should be fine.