Page 848 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 823

VetBooks.ir to relieve obstruction is noted initially, followed by prior to induction of anaesthesia. At surgery, the
bowel is untwisted, and any compromised intestine
a decrease and eventually absence of motility (ileus).
Venous and luminal occlusion will result in fluid
accumulation in the affected segment of small intes- is resected. Often, so much of the ileum is compro-
mised that it is impossible to carry out an end-to-end
tine and increased intraluminal pressure. anastomosis. In these cases, a jejunocaecal anasto-
The condition is worsened by secretion of more mosis (end-to-side or side-to-side) is performed. If
fluid by the intestinal wall. Arterial blood usually >60% of small intestine is involved, euthanasia is
continues to enter the affected segment, furthering usually recommended because of the potential for
development of oedema. Eventually, the intestine maldigestion and malabsorption.
orad to the volvulus becomes distended and gastric
distension will eventually develop. Sequestration of Prognosis
fluid in the small intestine may produce dehydration. The prognosis is generally poor to fair, due to the
Necrosis of the intestine creates leakage of protein, large amount of small intestine that can be involved
red blood cells and bacteria, which can result in peri- and the frequency of complications associated with
tonitis and endotoxic shock. small-intestinal resection. Intestinal adhesions,
abscessation of the anastomosis site and func-
Clinical presentation tional obstruction of the anastomosis are common
An acute onset of typically violent colic is observed. complications.
The severity of pain may decrease in some cases con-
current with intestinal necrosis. Moderate abdomi- MUSCULAR HYPERTROPHY
nal distension can be evident. A marked elevation OF THE ILEUM
in heart rate is common and respiratory rate can be
concurrently elevated. Body temperature is usually Definition/overview
normal but may be decreased in advanced stages of Hypertrophy of the muscular layers of the ileum, with
disease. Spontaneous NG reflux is uncommon. accompanying reduction of the lumen, can result in
obstruction of the intestinal lumen (Fig. 4.151).
Differential diagnosis
Other causes of small-intestinal strangulation
including pedunculated lipoma, intussusception,
epiploic entrapment and herniation. 4.151

Diagnosis
Small-intestinal distension is usually palpable p/r.
Thickening of the intestinal wall may be appreci-
ated in some cases. Passage of the gastric tube will
often yield spontaneous or provoked reflux fluid,
but gastric decompression may not result in any
improvement in clinical signs. Hypovolaemia devel-
ops rapidly. Abdominocentesis usually yields a sero-
sanguineous fluid with an increased nucleated cell
count and total protein level. On ultrasonographic
examination, distension of small-intestinal loops (>5
cm) with absence of motility can be appreciated. An Fig. 4.151 A case of severe ileal hypertrophy
increase in intestinal-wall thickness may be present. (arrow). This horse experienced several episodes
of medical colic before requiring an exploratory
Management laparotomy. Massive distension of the entire small
Surgical intervention is required. Cardiovascular intestine was found, reflecting the chronic nature of
compromise is common, and stabilisation is required the ileal hypertrophy.