Fatal hemorrhage associated with incarceration of small intestine by the epiploic foramen in three horses.

Abstract

I ncarceration and strangulation of small intestine through the epiploic foramen has been reported as a cause of colic in horses (1-6). The condition was recorded in 95 of 1301 horses (7.30o) undergoing exploratory celiotomy for the treatment of colic (1,5-8). An increased prevalence has been reported in Thoroughbreds (5,9), although the condition has been diagnosed in horses of mixed breeding (1). No relationship to sex has been observed (1,5,6). It is considered to affect horses of at least seven years of age (2); however, cases have been documented from one year of age (8). The anatomic features of the epiploic foramen have been described previously (10). With increasing age, the right lobe of the liver commonly atrophies (10). This may result in enlargement of the epiploic foramen and thus predispose to herniation of bowel (2). Clinical signs and hematological values are extremely variable and often not those normally associated with incarceration and strangulation of the small intestine. The pain exhibited may range from mild, with periods of abeyance, to very severe but controlled with analgesics, to intractable. Color of the oral mucus membranes may range from normal to blanched or severely congested, while capillary refill time may be normal or delayed up to six seconds. The heart and respiratory rates may be mild to significantly elevated in the ranges 50-150 and 12-60 per minute, respectively. Nasogastric intubation may result in the siphoning of variable quantities of gas or acidic fluid; however, in many cases no reflux is obtained. Mild abdominal distension may be present and intestinal sounds audible on auscultation. The hydration and acid-base status of horses with strangulated bowel may be normal or show mild hemoconcentration and metabolic acidosis. The findings on palpation per rectum may vary from no significant abnormality to the detection of distended coils of small intestine. Abdominocentesis frequently yields serosanguinous fluid of normal protein and leukocyte count. Diagnosis of incarceration of small intestine through the epiploic foramen is made on exploratory celiotomy through the ventral midline. During the period May of 1974 to May of 1990, 1085 horses underwent exploratory celiotomy for colic at the Ontario Veterinary College. A diagnosis of incarceration of the small intestine through the epiploic foramen was made in 26 cases. Three of these died or were euthanized as a result of uncontrollable hemor-