Page 853 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

828 CHAPTER 4

VetBooks.ir Clinical presentation intestinal contents. In most cases the intestine is
non-viable and requires resection. It is possible to
Clinical signs are inconsistent, which may ham-
per diagnosis. Some horses may display acute vio-
to reduce the entrapment, especially if the condi-
lent onset of colic, which subsides and is followed rupture the vena cava or portal vein while trying
by depression. Other cases may show no signs of tion has resulted in compromise of the vascular wall.
abdominal pain and/or gastric reflux. Despite the This is a fatal complication.
presence of a necrotic bowel, some horses may have
normal vital parameters. Absence of clinical signs of Prognosis
shock may be explained by the fact that the infarcted The prognosis is guarded to fair depending on
bowel is in an enclosed area, which may slow down whether resection is necessary or not. Reported
the absorption of endotoxin. Severe hypovolaemic long-term survival rates vary from around 35% to
shock or even sudden collapse is possible if the portal 70% and are often poorer than for other small-intes-
vein or vena cava ruptures. tinal surgical conditions. The most common com-
plication postoperatively is ileus.
Differential diagnosis
Any other small-intestinal obstructive disease such INGUINAL RUPTURE
as strangulated lipoma, volvulus, intussusception
and entrapment in a mesenteric rent can cause simi- Definition/overview
lar signs. Inguinal ruptures result from herniation of intestine
through the inguinal canal followed by rupture of
Diagnosis the peritoneum or, less commonly, the vaginal tunic,
Diagnosis may be difficult. The small intestine is resulting in the presence of intestinal loops in the
incarcerated very cranially in the abdomen, there- subcutaneous tissues of the scrotal region. It is often
fore small-intestinal distension may not be palpable referred to as a direct inguinal hernia.
p/r. NG reflux may not be present until late in the
disease because of the typical involvement of dis- Aetiology/pathophysiology
tal portions of the small intestine. In most cases an Inguinal rupture is most commonly seen in foals
increase in peritoneal fluid protein level is noted. after parturition, secondary to a traumatic rupture
Peritoneal fluid WBC count may also be increased, of the vaginal tunic or peritoneum, probably caused
but this is not consistent. Free blood in the abdo- by compression during parturition. The intestine
men may be present if rupture of one of the main passes through a rent in the parietal tunic and scro-
vessels has occurred. While performing ultrasono- tal fascia. Inguinal rupture may also be caused by a
graphic examination of the abdomen, the right mid- fall or a jump in the adult horse and can be associated
dle body wall region should receive special attention. with a considerable length of intestinal herniation.
If non-motile and oedematous small-intestinal loops
are detected in this region, an epiploic entrapment Clinical presentation
should be suspected. Definitive diagnosis is achieved Foals are usually presented for depression or mild
at surgery. colic signs and a pendulous swelling extending from
the inguinal region to the cranial aspect of the pre-
Management puce. If strangulation is present, the colic signs will
Surgery is required, and reduction of the entrapped be more severe. Friction between the swelling and
loop is performed. In some cases of severe distension the inner thigh may result in cold, oedematous or
and oedema of the affected intestine, resection of necrotic skin locally. Loops of bowel can usually be
one of the branches involved in the entrapment may palpated subcutaneously and in some cases, there is
be necessary to successfully reduce the entrapment. evidence of peristalsis underneath the skin. The her-
Alternatively, an enterotomy can be performed nia is usually difficult or impossible to reduce com-
1 metre proximal to the obstruction to empty the pared with a non-ruptured inguinal hernia. Inguinal