Digestive System - Intussusception



Q: Dr. Mike, I really have two questions. I have been breeding Standard and miniature schnauzers for a very long time (30+ years for minis). One of my two year-old standards just went through surgery to have much of his bowel removed. This was finally diagnosed after 4 months of bloody diarrhea and several medications, biopsies, blood tests, cultures. It was also found that he had Proteus variabilis and Enterococcus in the colon. Two days after the surgery, his rbc went down to 7 and he has had transfusions. His owners have spent much on this dog and are distraught - not so much for the money as for the dog.

1. What are the common causes of intussusception? 2. I read, not too long ago, some research on Advantage....it indicated that some dogs that were allergic to it, developed internal problems and some died. I dismissed the articles because I do not use Advantage and simply made a mental note to tell people not to use it. I did not know that the owners of this SS were using it. Could this be a cause of the problem? Thanks very much . if this is a genetic problem, then I want to go back into the lines and check it out. I appreciate any help.

A: I am not aware of the studies you mention concerning Advantage (Rx) causing gastro-intestinal problems. I did check the veterinary database I have access to. There have been some skin reactions at the site of application reported. New medications frequently generate a lot or reports of adverse reactions and it is important be careful when using them to consider this. It is very hard to distinguish between reactions that would have occurred in any case and those from a new medication, especially a medication with a prolonged effect.

Intussusception occurs when a section of intestine over-rides another section, trapping it inside in a telescoping effect. This cuts off the circulation to the sucked up section of intestine and it dies if the situation is not relieved. The dead section of intestine then leads to the death of the affected dog as infection and shock occur.

Intussusceptions generally occur as a secondary problem to some disorder or disease that causes increased intestinal mobility or inflammation. Chronic parasite infestation may be the most common cause but anything that causes chronic intestinal disease can lead to an intussusception. There are times when intussuceptions occur for no apparent reason so it is likely that primary intussusception can occur. They have been reported following ingestion of foreign bodies, trauma, ovariohysterectomy surgery, infiltrative or inflammatory bowel diseases and other conditions that cause intestinal irritability.

Intussusception can be chronic sometimes. It can also be a "come and go" problem -- intussuscpetions occasionally will resolve on their own and then recur. I have removed one surgically, put the remaining intestinal ends back together and watched a new intussusception form right at the same site.

It is probably not possible to determine the whole story of the puppy's death without hearing from the vets involved and the owner's perspective, too. Even then, unless a necropsy (autopsy) was done, it may be impossible to tell what the initiating cause might have been. The bacteria you mentioned are both pretty common invaders of any damaged tissue.

Hope this helps some.


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...