Page 852 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 827

VetBooks.ir Differential diagnosis opening of the epiploic foramen becomes wider, facili-
tating entrapment of the small intestine. A link between
Any other obstructive lesion of the small intestine,
such as volvulus, strangulated lipoma or mesenteric
been reported. In the UK, many cases occur in the
rent, can produce similar clinical signs. aerophagia and epiploic foramen entrapment has also
winter months when animals are stabled.
Diagnosis The distal jejunum and ileum are the most com-
Distended loops of small intestine are typically pal- monly involved, possibly due to their long mesentery.
pable p/r. NG reflux may be present, depending on Entrapment can be from right to left or left to right.
the duration of obstruction. Ultrasonographic exam- In the right-to-left herniation the small intestine passes
ination of the abdomen may demonstrate distended from the peritoneal cavity through the epiploic fora-
small-intestinal loops, potentially with intramural men and into the omental bursa (left side) (Fig. 4.155).
oedema. If necrosis has occurred, serosanguineous However, the left-to-right entrapment is more com-
fluid with an increased nucleated cell count and total mon, where the intestine enters from the visceral side of
protein level will be present on abdominocentesis. the liver to lie subsequently between the right liver lobe
and the dorsal body wall.
Management
Surgical correction is required. At surgery, the incar-
ceration is reduced followed by a resection and anas- 4.154
tomosis of the compromised intestine. Often the 4
mesodiverticular band contains a vitelline artery and
the potential role of that artery in the blood supply
to the jejunum should be evaluated prior to resection.

Prognosis 1
The prognosis is fair when resection is needed. The
prognosis is worse if small-intestinal volvulus is
present concurrently.

EPIPLOIC FORAMEN ENTRAPMENT 2 3

Definition/overview Fig. 4.154 Laparoscopic view of the opening of the
The epiploic foramen is a virtual space on the vis- epiploic foramen (1), the pancreas (2), the duodenum
ceral surface of the liver, where small intestine can (3) and the liver (4).
become incarcerated (Fig. 4.154). It is an uncom-
mon condition. Thoroughbreds and crosses, and 4.155
male animals appear to be predisposed.

Aetiology/pathophysiology
The epiploic foramen lies on the visceral surface of the
liver near the portal fissure. It is a narrow opening of
approximately 4–10 cm in diameter, limited cranially
by the hepatoduodenal ligament and caudally by the
junction between the pancreas and the mesoduode-
num. The structures bordering the epiploic foramen
are the caudate process of the liver, the caudal vena cava
dorsally, the right lobe of the pancreas and the portal Fig. 4.155 Post-mortem view of a right-to-left epiploic
vein ventrally. It has been hypothesised that the caudate foramen entrapment. Note the typical appearance of
process of the liver atrophies with age and the potential small-intestine haemorrhagic strangulation.