Author

Stephen J. Birchard DVM, MS, Diplomate ACVS

Monday, October 7, 2013

Intussusception in Dogs and Cats: How to Make Them Go Away and Not Come Back!



Fig. 1: Duodenal intussusception in a dog due to a leiomyoma
Many years ago I was operating on a puppy with severe enteritis that we suspected had an intussusception. While I was doing the abdominal exploratory, an intussusception developed in a segment of bowel while I was watching it. Since it was very acute, as in, just happening before my eyes, reducing it was easy. But I was amazed at how easily it occurred and I thought, what can we possibly do to prevent more of these from happening in this puppy? Also, what an odd thing this is for the bowel to do.

Intussusception is telescoping of one bowel segment into another and usually occurs at the ileo-ceco-colic junction in dogs and in the jejunum in cats.1 (Figs. 1-2) Intussusception occurs secondary to other disease processes such as parvovirus enteritis, parasites, linear foreign body, or even neoplasia (e.g. ileo-ceco-colic tumors or duodenal tumors as in Beetle, the subject of a previous blog). One study in cats found that the most common causes of intussusception in older cats were inflammatory bowel disease and intestinal lymphosarcoma.1 These primary diseases probably cause changes in motility that causes one segment of bowel to telescope into an adjacent segment. The ileo-ceco-colic region in dogs is a common area of intussusception since the ileum is smaller in diameter than the colon.
Fig. 2: Ileo-colic intussusception in a dog
If not treated promptly, the intussusceptum (the portion of bowel inside the intussuscipiens) will become strangulated and necrotic. (Fig. 3) Intestinal resection and anastomosis is necessary in intussusceptions that are irreducible, have resulted in damage to the bowel, or are associated with an invasive neoplasm.
Fig. 3: Resected ileo-colic intussusception in a dog. The
intussuscipiens has been opened to show the intussusceptum.

Diagnosis

Intussusception causes acute intestinal obstruction and should be suspected in any dog or cat with acute vomiting and diarrhea especially if a movable, sausage shaped mass is palpable in the abdominal cavity. The mass is usually painful on palpation. Animals with known primary intestinal disease such as inflammatory bowel disease or infectious enteritis should be considered predisposed to intussusception and diagnostics preformed to rule it out.

Plain film radiographs typically reveal evidence of bowel obstruction with intestinal dilation particularly of the portion of the jejunum just upstream from the obstruction. Ultrasound can provide further evidence of intussusception by revealing the telescoped intestinal segment and a target like appearance on cross section of the affected area. (Fig. 4)
Fig. 4:Ultrasound of a dog with an intussusception. In this cross section of the affected
intestine note the layered intestinal walls creating a target appearance. (arrows)
Upper GI contrast study or barium enemas are additional methods to demonstrate the intussusception by outlining the intussusceptum as a filling defect within the bowel. (Fig. 5)
Fig. 5: Barium enema of a dog with an ileo-colic intussusception showing
a distinct filling defect within the ascending and tranverse colon
.

Treatment

Intussusception is a surgical emergency since it causes intestinal obstruction and strangulation of intestine. Fluid and electrolyte abnormalities should initially be treated and abdominal exploratory performed promptly after diagnosis.

Perform a thorough exploratory of all abdominal organs and attempt to indentify any predisposing disorders such as foreign body or neoplasm. Find the intussusception and isolate it from the peritoneal cavity with sponges. Attempt to reduce the intussusception by gently pulling on the intussusceptum. Pushing the intussusceptum out of the intussuscepiens by massaging it may also help.

Carefully examine the intestine and determine if it is viable. Inability to reduce the intussusception and finding non-viable intestine are indications for resection and anastomosis. Luminal disparity may make anastomosis challenging especially if the ileum is being sutured to the colon. Incising the antimesenteric aspect of the smaller sized intestine will enlarge the lumen to allow it to match up (more on this when we discuss subtotal colectomy for megacolon in cats).

Surgical plication of the intestine is a method to help prevent recurrence of intussusception.2,3 Plicate the bowel in gentle or “lazy” loops using serosal sutures to maintain the orientation. (Figs. 6,7)
Fig. 6: Surgical plication of the small intestine to prevent intussuception.
(from Bright RM. Surgery of the intestine. Saunders Manual of Small Animal
Practice
. Birchard and Sherding, editors. Elsevier, 2006, pg. 742.) 
Studies of the efficacy of plication are mixed and one study found complications associated with the technique. I usually will plicate just the local area of bowel by making 2-3 loops rather than doing the entire small intestine. Plication is particularly important if the intussusception was only reduced and not resected. 
Fig. 7: Several loops of bowel have been plicated with 4-0 polypropylene.
The sutures are only placed through the serosal layer or slightly deeper but are
not full thickness.
Always submit the resected intestine for histopathology to identify any underlying diseases. Other than plication, medically prevent recurrence of intussusception by indentifying and treating the etiology. Postoperative care is otherwise similar to that described for intestinal biopsy and enterotomy.

References

1. Jamie M. Burkitt; Kenneth J. Drobatz; H. Mark Saunders; Robert J. Washabau. Signalment, history, and outcome of cats with gastrointestinal tract intussusception: 20 cases (1986–2000) J Am Vet Med Assoc 2009;234:771–776

2. Oakes MG, Lewis DD, Hosgood G, Beale BS. Enteroplication for the prevention of intussusception recurrence in dogs: 31 cases (1978-1992. J Am Vet Med Assoc. 1994 Jul 1;205(1):72-5.
3. Applewhite AA, Hawthorne JC, Cornell KK. Complications of enteroplication for the prevention of intussusception recurrence in dogs: 35 cases (1989-1999. J Am Vet Med Assoc. 2001 Nov 15;219(10):1415-8.