Page 828 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 803

VetBooks.ir become less obstructive. In some cases, pelleted feed 4.129
may be required for the duration of a horse’s life.
Surgical treatment for bowel obstruction asso-
ciated with adhesions includes resection and anas-
tomosis or bypass of the affected bowel, with or
without adhesiolysis. Laparoscopic adhesiolysis has
been used successfully in a small number of equine
cases.

Prevention
Methods for preventing postoperative adhesion for-
mation that have been evaluated include periopera- Fig. 4.129 Mucosal surface of the small intestine
tive treatments with s/c administration of heparin or in a horse with intestinal lymphosarcoma. Note the
verapamil (a calcium channel blocker), i/v administra- markedly enlarged Peyer’s patches (arrow).
tion of a combination of antimicrobials and flunixin
meglumine or dimethylsulphoxide, intraperitoneal
administration of solutions of high-molecular weight 4.130
heparin, omentectomy and postoperative peritoneal
lavage. However, despite all the experimental and
clinical studies, no definitive method for adhesion
prevention in horses has been developed.

Prognosis
Horses with adhesions causing clinical signs have
a reported prognosis of between 0% and 20% for
long-term survival.

GASTROINTESTINAL NEOPLASIA
Fig. 4.130 Multiple large mesenteric lymph nodes are
Definition/overview evident in this horse with intestinal lymphosarcoma.
Neoplasia of the GI tract is a relatively rare occur-
rence in horses. Lymphosarcoma is the most com- 4.131
mon condition (Figs. 4.129, 4.130) and gastric
squamous cell carcinoma (SCC) is the second most
common (Fig. 4.131). Other, rarely encountered
neoplasias include gastric leiomyosarcoma, gastric
leiomyoma, gastric adenocarcinoma, intestinal
leiomyosarcoma, intestinal leiomyoma, intestinal
adenocarcinoma, intestinal myxosarcoma, dissem-
inated leiomyomatosis, omental fibrosarcoma and
mesothelioma.

Aetiology/pathophysiology
The aetiology is unknown. The pathophysiology is
variable. Clinical signs develop subsequent to intes-
tinal obstruction, maldigestion/malabsorption,
blood loss, peritoneal effusion and chronic inflam- Fig. 4.131 Gastric squamous cell carcinoma in a
matory response. 19-year-old horse that presented for weight loss.