Page 856 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 831

VetBooks.ir reduce it back into the abdomen because of the Prognosis
The prognosis is excellent in foals. In adults, if
location of the intestinal segment that is involved.
A unilateral or bilateral castration is performed to
tion is avoided, the prognosis is good. However,
prevent future herniation, followed by closure of the condition is diagnosed rapidly and a resec-
the vaginal tunic and the superficial ring. if strangulation has occurred, the prognosis is fair
to poor.

DISORDERS OF THE CAECUM

CAECAL RUPTURE Diagnosis
Haematology may be normal shortly after rup-
Definition/overview ture; however, neutropenia with a left shift and
Caecal rupture is a rare and invariably fatal condi- degenerative changes in neutrophils will develop.
tion because of the rapid onset of septic peritonitis. Total plasma protein levels will decrease as
peritonitis progresses, while PCV will increase.
Aetiology/pathophysiology Excessive flocculent peritoneal fluid will be evident
Rupture may occur due to marked distension or ultrasonographically. Fibrin may be apparent.
devitalisation of the caecal wall. Caecal rupture Abdominocentesis should be performed. Dark,
can occur secondary to caecal tympany, impaction foul-smelling peritoneal fluid will often be recov-
or infarction. Idiopathic caecal rupture can occur ered. A gritty feel to the serosal surface may be
in mares following parturition (see Fig. 2.59), in detected p/r. None of these findings can be used
hospitalised horses treated with NSAIDs and in to differentiate caecal rupture from rupture of
the absence of any history of disease. It has also another intestinal viscus. Definitive diagnosis is
been suggested that severe tapeworm infection obtained at surgery or necropsy.
may be associated with caecal rupture. It is not
uncommon for caecal rupture to occur without Management
any prodromal signs. The gross contamination There are no viable treatment options.
of the abdomen that occurs with caecal ruptures
results in the rapid development of severe septic Prognosis
peritonitis. Caecal rupture is invariably fatal (Fig. 4.158).

Clinical presentation
There may be a short period following caecal rupture
when the horse appears to have improved because of 4.158
the immediate relief of severe distension. Shortly
afterwards, progressive signs of depression, colic,
toxaemia, dehydration, cardiovascular compromise,
sweating and shaking will develop. Heart rate will
increase and can be severely elevated. Mucous mem-
branes may be dark red, purple or blue and CRT
may be markedly prolonged. Borborygmi will be
decreased or absent.
Fig. 4.158 A post-mortem view of a large caecal
Differential diagnosis rupture secondary to a long-term caecal impaction.
Septic peritonitis of other causes, severe enterocoli- Note the very severe acute peritonitis and serosal
tis, septicaemia and pleuritis should be considered. inflammation. (Photo courtesy Graham Munroe)