Page 838 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 813

VetBooks.ir Differential diagnosis be normal in some cases, particularly if rupture has
occurred very recently or if gastric contents have been
Septic peritonitis of other causes, severe enterocoli-
tis, septicaemia and pleuritis should be considered.
sequestered initially by omentum. Definitive diagno-
sis is obtained at surgery or necropsy.
Diagnosis
The presence of gastric reflux does not rule out the Management
presence of a gastric rupture. Haematology may be Once the stomach has ruptured, severe septic peri-
normal initially; however, neutropenia with a left shift tonitis develops rapidly. There are limited reports of
and degenerative changes in neutrophils will develop. successful surgical repair of seromuscular tears, and
Total plasma protein levels will decrease as peritoni- one report of successful repair of a tear that involved
tis progresses, while the PCV will increase. Excessive all but the serosal layer. Once there is gross contami-
flocculent peritoneal fluid will be evident ultrasono- nation of the abdomen, there are no viable treatment
graphically. Fibrin may be apparent. Abdominocentesis options.
should be performed. The fluid may have a gross
appearance of ingesta in some cases. In others, variable Prognosis
elevations in WBC count and degenerative changes Gastric rupture with abdominal contamination is
in neutrophils may be present. Peritoneal fluid may invariably fatal.

DISORDERS OF THE SMALL INTESTINE

DUODENAL ULCERATION Clinical presentation
Clinical signs from duodenal ulceration are the same
Definition/overview as those from severe EGUS, in part because EGUS
Duodenal ulceration is less common than EGUS, is often present concurrently. In foals, bruxism,
but it is more difficult to diagnose and can be more excessive salivation, rolling on the back and anorexia
serious. Typically, EGUS is present concurrently. may be observed. Diarrhoea may also be present.
Duodenal ulcers are most common in horses less Foals with duodenal ulcers may be more likely to be
than 2 years of age, and foals only a few days old may pyrexic or depressed. In older horses, mild to mod-
be affected. Perforating ulcers are more common in erate colic signs may be present. Decreased appetite
the first 2 months of life. (particularly for grain), weight loss and ill-thrift may
also occur. If duodenal stricture is present, poor
Aetiology/pathophysiology growth, intermittent colic, bruxism, excessive sali-
The aetiology of duodenal ulceration is not well vation, depression and fever may be observed.
understood. In basic terms, duodenal ulceration
develops when protective mechanisms are over- Differential diagnosis
whelmed. The most important protective mecha- EGUS is the main differential diagnosis. A variety
nism in horses is the presence of bicarbonate- rich of other causes of intermittent colic and diarrhoea
secretions. Factors affecting protective mech- should be considered.
anisms have not been adequately identified.
Segmental ulceration, often in the area of the Diagnosis
entrance of the bile duct, is most common. In Duodenoscopy (Fig. 4.141) is the standard for diag-
some cases, inflammation associated with ulcer- nosis and should be performed in all animals with
ation can result in duodenal stricture, which can consistent clinical signs, particularly those with
subsequently affect gastric emptying. Perforation severe EGUS or evidence of decreased gastric out-
of duodenal ulcers can occur, often with few pro- flow. Contrast radiography (barium series) is used
dromal signs. to identify delayed gastric emptying (>2 hours) and
duodenal strictures.