Colic, abdominal pain, is one of the most common equine emergencies. The most common cause of colic is a gastrointestinal tract problem. Although colic can be a life threatening disease, approximately 70% of horses with colic recover uneventfully either with no or minimal treatment, a further 25% require medical management such as analgesia and oral or intravenous fluid therapy, and only about 5% require surgery. Lesions found during colic surgery are numerous. Small intestinal strangulation and large colon volvulus (LCV) are two of the more common and serious lesions requiring surgery, and are useful for illustrating the principles of colic examination and surgery, as well as treatment and prevention of postoperative complications including endotoxemia, ileus, and adhesions.

Strangulating Small Intestinal lesion

A 14 year-old Arabian mare was referred to the Veterinary Teaching Hospital with a 24-hour history of moderate abdominal pain. At presentation, the horse was mildly painful and did not appear to be gas distended. On physical examination, the heart rate (HR) was 88 bpm, respiratory rate (RR) and rectal temperature (T^oF) were within normal limits, oral mucous membranes (mm) were pink, dry, and the capillary refill time (CRT) was 2–3 sec, intestinal tract sounds were absent. Rectal examination revealed several loops of distended small intestine, and approximately 15L of nasogastric reflux was obtained.

Hematology revealed a hematocrit of 39%, protein of 8.5 g/dL, fibrinogen of 500mg/dL, and 8,1000 leukocytes/mL. Serum biochemistry revealed mild hyperglycemia, hypophosphatemia, hyperproteinemia, elevated bilirubin, CK, AST, mild hypochloremia, and mild acidosis. Peritoneal fluid was serosanguinous with 50,000 cells/mL and protein of 3.5 g/dL. Ultrasound also revealed several loops of distended small intestine.

The horse was initially treated with fluids, however remained persistently painful. Based on the persistence of pain, duration of colic, distended small intestine, and abnormal peritoneal fluid, surgery was recommended. At surgery the horse was found to have a strangulating lipoma of the distal jejunum; approximately 3 m of jejunum was strangulated. Following transection of the lipoma pedicle, the small intestine regained its color except for approximately 0.5 m. Therefore 0.5–1 m of distal jejunum was resected and anastomosed using an end-to-end, simple continuous, two-layer technique. Postoperatively the horse was treated with flunixin meglumine, antibiotics, fluids and electrolytes, lidocaine and acepromazine to stimulate motility; heparin, DMSO to prevent adhesions. There were no postoperative complications.

Large Colon Volvulus

An 11-year-old Holstein mare was referred to the Veterinary Teaching Hospital with an acute onset of severe abdominal pain. At presentation the horse was severely painful and gas distended. There were several abrasions on her head and tuber coxae. Physical examination revealed a HR of 60 bpm, RR and ToF were within normal limits, mm were pale and dry, intestinal tract sounds were absent. Rectal examination and nasogastric intubation was not performed because of the severity of the horses pain.

Hematology revealed a hematocrit of 40%, protein of 6.5 g/dL, fibrinogen of 300 mg/dL, and 8,100 leukocytes/mL. Serum biochemistry revealed moderate hyperglycemia, mild azotemia, hypoalbuminemia, hypochloremia, mild acidosis, elevated bilirubin, CK, SDH, and anion gap. No abdominocentesis was performed because of the severity of pain and gas distention.

Based on the severity of pain and gas distention, the horse was taken to surgery. A 360^o counterclockwise (dorsal lateral-ventral medial) volvulus at the level of the cecocolic ligament was found. The colon was decompressed and derotated. The viability of the large colon was questionable; therefore a large colon resection and anastomosis was performed, using a hand-sewn side-to-side anastomosis technique.

Postoperatively the horse was treated with flunixin meglumine, antibiotics, fluids and electrolytes, lidocaine for analgesia, plasma with antibodies to lipopolysaccharide, polymixin B, DMSO, heparin, and dextrans specifically for endotoxemic shock. The horse showed severe signs of endotoxemia, including tachycardia, leukopenia, elevated hematocrit with hypoproteinemia, and toxic membranes postoperatively. However after 24–48 hours of aggressive medical therapy the horse recovered uneventfully, and is currently doing well.