Diagnosing Chronic Colic with Ultrasound: ACVIM 2006

Evaluating and treating prolonged cases of colic--those lasting three days or more--can be problematic. Horses with prolonged colic generally aren't in enough pain for surgery, and they respond temporarily to medicines. But the condition persists, many times puzzling the clinician attempting to resolve it. Abby M. Sage, VMD, MS, Dipl. ACVIM, of the University of Minnesota (UM), described the use of ultrasound to help diagnose chronic colic cases at the American College of Veterinary Internal Medicine Forum in Louisville, Ky., on June 2.

A detailed history of the animal, physical examination, and rectal palpation provide the most useful information in determining the cause of colic. Veterinarians can also use hematology (blood profile), serum biochemistry, radiographs, abdominocentisis, endoscopy, laparascopy, and exploratory laparotomy to learn more about the case. However, ultrasonographic examination can also give a window into abdomen, and it is rapid and non-invasive.

Sage explained that all veterinarians are trained to ultrasound colic cases. "We do it on all the colics," she said. "We do it on the standing horses when at all possible. You can perform an accurate and adequate ultrasound in 10 minutes. It isn't perfect, and there are limitations, but we've found it to be extremely valuable...there are a lot of things we can do right away to help the horse (if we know what's amiss in the digestive system)."

The technique involves using ultrasound on the entire abdomen, "paralumbar (in the flank area, just down from the lumbar vertebrae) to the sixth intercostal space (between the sixth and seventh rib) dorsal to ventral (top to bottom) in a longitudinal plane," she explained. "It's important to cover the whole abdomen and go all the way forward."

Sage and her colleagues mapped the normal viscera (large internal organs) and looked at the effects of fasting and sedation on the appearance of the digestive tract. She described these features to the veterinarians in attendance at the meeting.

"It's very important to have the knowledge of normal viscera," Sage noted. Before making a diagnosis of chronic colic via ultrasound, "It's also important to know whether the horse has been fed or not," because certain structures will be visible in the fasted horse in a different area of the abdomen than if the horse had been fed. This could be misleading when making a diagnosis.

"Ultrasound is an invaluable tool in assessing chronic colic," she concluded. "Further studies to explore normal and abnormal findings will expand the ability of the veterinarian to interpret it more accurately."

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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