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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.
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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.
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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)
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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)
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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)
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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.
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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.