Chronic intestinal pseudo-obstruction

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Chronic intestinal pseudo-obstruction in a Bernese Mountain Dog showing characteristic histological changes. Smooth muscle cells (colored brown) are prominent in the lamina muscularis mucosae (→) and almost absent in tunica muscularis(►)[1]

Chronic idiopathic pseudo-obstruction (leiomyositis) is a severe gastroenteritis syndrome characterized by ileus without a mechanical basis[2].

A predilection has been noted in the labrador Retriever and Bernese Mountain Dog but many breeds can be affected, with no age or sex predilection.

This condition is 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[1].

Only a few cases of this disease have been reported in dogs[3].

These dogs typically present with a distended, painful abdomen, chronic anorexia, vomiting and diarrhea non-responsive to therapy[4].

Urinalysis and blood tests are usually unremarkable, although severe cases may present with metabolic alkalosis due to intestinal loss of anions[5].

A presumptive diagnosis can be based on clinical findings supported by radiographic and ultrasonographic examinations revealing dilated intestines with air-fluid level[6].

A definitive diagnosis requires histological examination of biopsied intestinal tissues, showing characteristic small and large intestinal atrophy and infiltration of serosa with mononuclear cell infiltration, as well as fibrosis of the tunica muscularis[7]. Occasionally, degeneration of smooth muscle fibers and diffuse inflammatory cell infiltration in the tunica muscularis of the stomach and/or bladder, submucosal plexi and myenteric plexi[8].

Several full thickness biopsies from dilated and non-dilated tracts of the alimentary canal should be obtained to help differentiate from other causes of ileus such as megacolon[9].

Exploratory laparotomy usually reveal severely dilated intestinal loops with a flaccid wall and watery contents.

Chronic pseudo-obstructive ileus is usually refractory to therapy and patients often die or require euthanasia[10].

References

  1. 1.0 1.1 Vandenberge, V et al (2009) Chronic intestinal pseudo-obstruction in a Bernese Mountain Dog. Vlaams Diergeneeskundig Tijdschrift 78:117-120
  2. Antonucci A et al (2008) Chronic intestinal pseudo-obstruction. World Journal of Gastroenterology 14:2953-2961
  3. Couraud L et al (2006) Intestinal pseudo-obstruction, lymphocytic myosistis and atrophy of the muscularis externa in a dog. Vet Rec 159:86-87
  4. Beijer HA & van den Ingh TS (2012) Gastro-intestinal lymphocytic and sclerosing leiomyositis (pseudoobstruction) in a dog. Tijdschr Diergeneeskd 137(10):666-669
  5. Arrick RH & Kleine LJ (1978) Intestinal pseudo-obstruction in a dog. J Am Vet Med Assoc 172:1201-1205
  6. Lamb WA & France MP (1994) Chronic intestinal pseudoobstruction in a dog. Australian Veterinary Journal 71:84-86
  7. Moore R & Carpenter J (1984) Intestinal sclerosis with pseudo-obstruction in three dogs. J Am Vet Assoc 184:830-833
  8. Petrus DJ et al (2001) Megacolon; secondary to autonomic ganglioneuritis in a dog. Vet Record 148:276-277
  9. Swayne DE et al (1986) Sclerosing enteropathy in a dog. Veterinary Pathology 23:641-643
  10. 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