Equis ISSN 2398-2977

Colon: displacement - right dorsal

Contributor(s): Debbie Archer, Sarah Binns, Rachel Murray, Peter Rakestraw

Introduction

  • Colon rotates laterally on its long axis around the cecum, to become positioned to the right of the cecum between the cecum and body wall. Different forms and degrees of obstruction may occur.
  • Cause: unknown.
  • Signs: usually acute colic with shock, sometimes mild and protracted course.
  • Diagnosis: rectal examination and exploratory laparotomy.
  • Treatment: surgical - repositioning of displaced large (ascending) colon.
  • Prognosis: good if diagnosed and corrected promptly.

Pathogenesis

Etiology

  • Unknown; possible causes:
    • Hypermotile or hypomotile state.
    • Gas accumulation.
    • Large (ascending colon) migrates into abnormal position within the abdomen with resultant simple obstruction (non-strangulating) or torsion (strangulating obstruction).

Predisposing factors

General
  • Most common in large-framed horse.

Pathophysiology

  • Large colon (ascending colon) rotates laterally on is long axis around cecum, often combined with torsion of varying degrees.
  • Viewed from the ventral aspect of the abdomen, the pelvic flexure may rotate in a counter-clockwise or clockwise direction; either way, the left ventral and left dorsal colon becomes malpositioned between the cecum and right body wall.
  • Colon also flexes, originating at transverse colon   →   dorsal and ventral portions of large colon partially occluded (non-strangulating obstruction).
  • May be accompanied by torsion of 180-360°, rarely at the same site as the flexion   →   further occlusion and strangulating obstruction (strangulation    Colon: torsion  ).

Timecourse

  • Usually acute.
  • Occasionally protracted, recurrent.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Monreal L et al (2010) Enteral fluid therapy in 108 horses with large colon impactions and dorsal displacements. Vet Rec 166 (9), 259-263 PubMed.
  • Smith L J & Mair T S (2010) Are horses that undergo an exploratory laparotomy for correction of a right dorsal displacement of the large colon predisposed to post-operative colic, compared to other forms of large colon displacement? Equine Vet J 42 (1), 44-46 PubMed.
  • Sherlock C E & Mair T S (2008) Concurrent atypical myoglobinuria and colon displacement in a filly. Equine Vet Educ 20 (5), 228-233 VetMedResource.
  • Huskamp B & Kopf N (1983) Right dorsal displacement of the large colon in the horse. Equine Pract 5, 20-29 VetMedResource.


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