Clinical Outcomes of Large Intestine Thickening (AAEP 2011)


Oftentimes one ailment in a horse can be indicative of another ailment waiting to be discovered. For example, large intestinal thickening (greater than or equal to 9 mm), is a known accurate indicator of colon torsion (twist) in surgical colic cases. But according to a team of University of California, Davis (UC Davis), researchers, a colonic torsion isn't the only ailment that a thickened large intestine could point to.

At the 2011 American Association of Equine Practitioners convention, held Nov. 18-22 in San Antonio, Texas, Beth Biscoe, DVM, described how severe large intestinal thickening appears on ultrasound. Biscoe, a former large animal ultrasound fellow at the UC Davis William R. Pritchard Veterinary Medical Teaching Hospital (VMTH), also characterized clinical outcomes of these cases.

Biscoe and her colleagues reviewed all the records of horses presented for abdominal ultrasound at the VMTH from 2003 to 2010. Twenty-five horses with large intestinal thickening greater than or equal to 9 mm were included in the study; these ranged in age from 3 to 28 years.

"Presenting complaints included colic, diarrhea, reduced appetite, weight loss, lethargy, fever, and hematuria (bloody urine)," Biscoe explained, adding that large intestinal thickening was the primary finding on the abdominal ultrasound.

Key study results included:

  • Only one horse was diagnosed with a colon torsion;
  • Eleven of 25 horses (44%) recovered completely;
  • One horse was classified as incompletely recovered as a result of recurring colic episodes;
  • Ten horses died or were euthanized (three of which had neoplasia [tumors] and three of which had colitis, or inflammation of the large bowel); and
  • Three horses did not have long-term follow-up records.

"The results support that severe large intestinal thickening can be associated with multiple disease etiologies (causes)," not just colonic torsion, Biscoe concluded. Veterinarians must carefully consider ultrasound findings along with each horse’s history and clinical signs in order to determine the root of each patient's problems and develop a proper treatment plan to give the animal the best chance of survival.

About the Author

Erica Larson, News Editor

Erica Larson, News Editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in three-day eventing with her OTTB, Dorado, and enjoys photography in her spare time.

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