Page 857 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

832 CHAPTER 4

VetBooks.ir CAECAL INFARCTION Management
Surgical resection of all infarcted tissue is required.
Definition/overview
extent of the infarction. The underlying cause must
Caecal infarction is an uncommon cause of colic. This may not always be possible, depending on the
also be addressed. If parasitism is thought to be the
Aetiology/pathophysiology cause, farm management should be evaluated.
Prior to the availability of avermectin anthelmin-
tics, Strongylus vulgaris infestation was the most Prognosis
likely cause of caecal infarction. Cyathostominosis The prognosis is fair as long as the infarction is not
may also be associated with caecal infarction. so large as to preclude resection. Prompt interven-
Disseminated intravascular coagulation (DIC) can tion is required to avoid the onset of peritonitis.
result in thrombus development in blood vessels,
including major vessels in the caecum. CAECAL TORSION
The pathophysiology is dependent on the
inciting cause. Extensive collateral circulation is Definition/overview
present in the caecum, therefore large thrombi Caecal torsion is a rare condition.
are required to cause caecal infarction. If a large
thrombus lodges in certain locations, blood sup- Aetiology/pathophysiology
ply to the caecum is compromised and ischaemic In most cases the aetiology of caecal torsion is
necrosis ensues. unknown. There is a report of caecal torsion in an
animal with anatomical abnormalities of the caeco-
Clinical presentation colic fold and in another case with multiple mesen-
Unless caecal rupture has occurred, most affected teric defects. Large-colon volvulus may predispose
horses present initially with mild to moderate to caecal displacement or volvulus. When this
abdominal pain. Tachycardia is present consistent occurs, the axis of rotation involves the dorsal mes-
with the degree of pain and underlying disease. Signs enteric attachment of the caecum.
of concurrent disease, particularly in cases thought
to be associated with DIC, may obscure signs of cae- Clinical presentation
cal infarction. Caecal torsion is accompanied by severe, acute pain
and metabolic derangements consistent with stran-
Differential diagnosis gulation of a large organ. Characteristic signs of
A variety of causes of colic must be considered. In colic are displayed.
addition, caecal infarction must be differentiated
from the underlying condition in cases associated Differential diagnosis
with DIC. Any form of strangulating intestinal accident would
be a differential diagnosis, particularly a large-colon
Diagnosis volvulus.
Clinical examination and palpation p/r are non-
specific. A thickened caecal wall may be evident on Diagnosis
ultrasonographic examination, but this is often dif- Physical examination findings are consistent with
ficult to interpret. A firm mass may be palpable in colic, but not specific for caecal torsion. Caecal
the right caudal abdomen; however, this finding is tympany may occur with caecal torsion as outflow
not pathognomonic for caecal infarction. Increases obstruction develops, in which case distension and
in peritoneal WBC count and protein level will be tympany of the right flank may be noted. Gaseous
present. Peritoneal fluid colour will be abnormal and distension of the caecum is often palpable p/r.
will worsen over time. Definitive diagnosis is made If caecal tympany does not develop, rectal find-
during surgery or necropsy. ings are unrewarding for a specific diagnosis of