Page 818 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 793

VetBooks.ir Clinical presentation 4.120
Two discrete clinical presentations have been
reported; acute colic and chronic low-grade
colic. The length of the intussusception partially
explains the difference in clinical presentation,
with short intussusceptions causing a partial intes-
tinal obstruction and a low-grade chronic colic,
and longer intussusceptions resulting in marked
luminal obstruction with more acute, severe signs
of discomfort.
Poor physical condition with varying degrees of
intermittent or continual abdominal pain is char-
acteristic of the chronic presentation. Affected
horses also are frequently anorexic and depressed.
With the acute presentation, signs of acute colic are
present. Affected horses may be in great pain, with
concurrent elevations in heart rate. Signs of toxae-
mia may be present if there is significant intestinal
compromise. Fig. 4.120 Typical cross-sectional appearance of
the ultrasonographic image of a small-intestinal
Differential diagnosis intussusception. In this image the intussusception
Differential diagnoses may include causes of chronic wall appears as concentric rings and is frequently
ill-thrift including heavy parasite burdens, intes- described as a bullseye or target lesion.
tinal neoplasia and inflammatory intestinal infil-
trates. Acute colic may be difficult to differentiate
from other causes of small-intestinal entrapment/ with a jejuno(ileo) caecostomy or a jejuno(ileo) caecal
obstruction. bypass. For caecocaecal and caecocolic intussuscep-
tions, reduction may be combined with a partial
Diagnosis typhlectomy if the caecum is considered to be of
Diagnostic evaluation is frequently consistent with questionable viability, and for jejunojejunal anasto-
luminal obstruction of varying degrees. Findings moses the affected segment may be resected and the
may include palpation of distended small intes- remaining bowel anastomosed.
tine p/r and NG reflux. Abnormalities found on Irreducible ileocaecal anastomosis has been
abdominocentesis are inconsistent. Palpating an treated by transecting the ileal stump and perform-
ileocaecal intussusception (right dorsal quadrant) ing an ileo/jejunocaecal anastomosis. However, this
has been a consistent rectal finding in some stud- method may leave a considerable amount of ileum
ies. An ultrasonographic ‘target’ or ‘bullseye’ lesion in the caecum, which may obstruct the caecocolic
consisting of concentric rings of intestine may be orifice or the newly created ileo/jejunocaecostomy.
seen (Fig. 4.120). A definitive diagnosis is made on Therefore, a technique has been described to resect
exploratory laparotomy. the ileum within the caecal lumen. Irreducible cae-
cocolic intussusception also presents a therapeutic
Management challenge and many cases are euthanased intraop-
Surgical correction is required. The details of the eratively. Surgical options include colostomy to assist
surgical intervention are dependent on the site, chro- correction and, failing that, intraluminal amputation
nicity and ability to reduce the lesion. For reducible of the intussusceptum. More recently, jejuno or ileal
intussusceptions, reduction may be used alone. For colostomy has been described for the treatment of
ileocaecal intussusceptions, this may be combined irreducible caecocolic lesions, with favourable results.