Page 832 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 807

VetBooks.ir winter, this may not be a particularly useful activity. reducing EGGD risk. Although it is widely believed
that NSAID administration is associated with ulcer-
T. axei is susceptible to most anthelmintics.
Prognosis ation of the glandular mucosa in adults and both the
glandular and non-glandular mucosa in foals, there
Excellent. is no epidemiological evidence to support this belief
when NSAIDs are used at label doses. The use of
EQUINE GASTRIC ULCER SYNDROME high-dose NSAID therapy is associated with the
development of EGGD lesions. Similarly, extended
Definition/overview duration therapy may be associated with increased
EGUS is a common problem affecting a wide range risk of EGGD. There is no evidence that Helicobacter
of horse types and usages. The equine stomach com- pylori plays a role in EGUS. The relatively linear
prises two distinct areas: the glandular and the non- relationship between exercise and ESGD is not seen
glandular (squamous) regions. Equine squamous in EGGD, and EGGD affects a wide range of horses
gastric disease (ESGD) refers to disease of the squa- not typically considered at high risk of ESGD.
mous mucosa, while equine glandular gastric disease
(EGGD) refers to disease of the glandular mucosa. It Clinical presentation
has been demonstrated that the risk factors, preva- In adult horses, decreased appetite (particularly for
lence and response to treatment of ESGD and EGGD concentrates), decreased performance, weight loss
are different. and changes in behaviour or rideability are com-
The glandular mucosa is protected primarily by mon complaints. Intermittent, low-grade colic, poor
mucus and bicarbonate secretion and prostaglandin- haircoat and lethargy may also be observed. In foals,
mediated mucosal blood flow. The non-glandular anorexia, intermittent colic, bruxism, salivation and
mucosa has fewer protective mechanisms and is more diarrhoea are most common. Some horses may have
prone to damage by hydrochloric acid and pepsin. severe lesions without any clinical signs. Gastric
ESGD is most common in high performance horses, rupture secondary to ulceration is very rare in adults
particularly close to the margo plicatus, which is the and uncommon in foals, but it can occur without
most acidic non-glandular area. In contrast, EGGD preceding signs. In adults and foals, clinical exami-
is most common in sport horses with Warmbloods nation is typically unremarkable with the possible
predisposed. exception of decreased body condition.

Aetiology/pathophysiology Differential diagnosis
EGUS is a multifactorial condition that results when A variety of causes of mild colic, partial anorexia or
the protective mechanisms of the gastric mucosa are ill-thrift must be considered. EGUS can occur con-
overwhelmed. Recognised risk factors for ESGD currently with other diseases, therefore a full clini-
include high carbohydrate diets, infrequent feed- cal evaluation is required.
ing, decreased roughage in the diet and intense exer-
cise. A relatively linear relationship exists between Diagnosis
increasing intensity of exercise and grain feeding Clinical signs may be suggestive but are not diag-
and increased risk of ESGD. nostic. Haematology is typically unremarkable, as
The causes of EGGD are not know at this point anaemia and hypoproteinaemia are uncommon even
in time, but it is believed that ‘stress’ may play a with severe ulceration. Faecal occult blood testing is
central role in its pathophysiology. This includes unreliable. Sucrose permeability testing is not use-
breed disposition and management factors related ful in adult horses. Gastroscopy provides a defini-
to behavioural stress such as multiple handlers and tive diagnosis. Full examination of the stomach
riders. Recently, exercising >4 and >5 days per week is essential and the absence of ESGD lesions can-
has been shown to increase the risk of EGGD in not be used to predict the presence, or absence, of
racehorses and show horses, respectively. This find- EGGD lesions. A grading system can be used to
ing suggests that rest days may be important in evaluate ESGD (Table 4.6, Figs. 4.134–4.138) while