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Radiographic features of canine ileus due to a linear foreign body, showing distended gas loops[1]

Canine ileus is a secondary disease caused by a physiological or anatomical interruption in the normal peristalsis of the intestine, resulting in weak irregular contractions leading to dysmotility and temporary or permanent obstruction[2].

Regardless of cause, ileus usually results in hypercolonization of proximal parts of small intestine with aerobic and anaerobic microorganisms[3], leading to mucosal release of nitrous oxide, and inflammatory mediator that directly interferes with gastrointestinal motility.

Ileus can affect any part of the intestine from stomach to rectum, but usually involves the small intestine.

Causes include:

Clinically affected dogs usually present with anorexia, vomiting, depression and mild abdominal distension.

Chronic idiopathic pseudo-obstruction is a severe syndrome caused by intestinal neuromuscular disease resulting from disorders of myenteric plexi, abnormalities of the interstitial cells of Cajal or primary involvement of intestinal smooth muscle cells[10]. These dogs typically present with a distended, painful abdomen, chronic anorexia, vomiting and diarrhea non-responsive to therapy.

Blood tests usually show varying degrees of metabolic alkalosis due to intestinal loss of anions.

On radiographs, anatomical ileus (due to obstruction) typically produces a nonuniform intestinal distension with a greater degree of distension than is seen with physiological ileus (often seen postoperatively). In chronic pseudo-obstructive cases, distended gas-filled loops are evident.

Ultrasonography may assist elucidation of pendulous movement of the ingesta inside a dilated bowel, invaginated intestines or an ingested intraluminal foreign body, non-uniform peristaltic activity of the dilated intestines or akinetic intestinal loops together with abdominal fluid accumulation[13].

Diagnosis is based on history of absent fecal production, exclusion of constipation and megacolon and radiographic and ultrasonographic evidence of ileus.

Treatment includes use of prokinetic drugs such cisapride, lactulose, use of warm enemas and enteral supplementation with glutamine[14] or S-methylisothiourea sulfate ( a nitrous oxide synthetase inhibitor)[15].

Most cases of post-operative ileus respond to therapy.

Chronic pseudo-obstructive ileus is usually refractory to therapy and requires euthanasia[16].


  1. Vet XRay
  2. Tsukamoto K et al (1999) The relationship between gastrointestinal transit and motility in dogs with postoperative ileus. Biol Pharm Bull 22(12):1366-1371
  3. Kutsyk IuB et al (2001) Application of enteral detoxication and decontamination in acute ileus. Klin Khir 1:18-21
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  8. Johnson CS et al (2007) Fibrosing gastrointestinal leiomyositis as a cause of chronic intestinal pseudo-obstruction in an 8-month-old dog. Vet Pathol 44(1):106-109
  9. Dvir E et al (2001) Chronic idiopathic intestinal pseudo-obstruction in an English bulldog. J Small Anim Pract 42(5):243-247
  10. 10.0 10.1 Vandenberge, V et al (2009) Chronic intestinal pseudo-obstruction in a Bernese Mountain Dog. Vlaams Diergeneeskundig Tijdschrift 78:117-120
  11. Cullen JJ et al (1998) Metabolism of superoxide dismutase during the adynamic ileus of endotoxemia. Eur Surg Res 30(5):326-333
  12. Jeong DH et al (2006) Multiple intestinal lymphomatous polyposis in a Jindo dog. J Vet Sci 7(4):401-403
  13. Manczur F et al (1998) Sonographic diagnosis of intestinal obstruction in the dog. Acta Vet Hung 46(1):35-45
  14. Ohno T et al (2009) Glutamine decreases the duration of postoperative ileus after abdominal surgery: an experimental study of conscious dogs. Dig Dis Sci 54(6):1208-1213
  15. Uenoyama S et al (2004) Improvement of intestinal motility using S-methylisothiourea in postoperative ileus. Am J Surg 187(1):93-97
  16. Johnson CS et al (2007) Fibrosing gastrointestinal leiomyositis as a cause of chronic intestinal pseudo-obstruction in an 8-month-old dog. Veterinary Pathology 44:106-109