Page 863 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

838 CHAPTER 4

VetBooks.ir 4.162 Clinical presentation
General
The clinical presentation can be highly variable and
depends on a number of factors. The spectrum of
disease can range from soft faeces with no other
clinical abnormalities, to peracute, fatal, necrohaem-
orrhagic enterocolitis. Diarrhoea is usually pres-
ent; however, clinical signs may develop before the
onset of diarrhoea. Varying degrees of dehydration
(Fig. 4.162), toxaemia, depression, abdominal pain,
cardiovascular compromise and abdominal disten-
sion may be present. DIC can occur (Fig. 4.163).
Fig. 4.162 Prolonged skin tent in the neck of a horse Non-strangulating infarction of the colon from DIC
estimated to be 10–12% dehydrated. should be considered in horses with colitis that dete-
riorate suddenly.
4.163
Salmonellosis
The ‘classical’ presentation of salmonellosis includes
fever, depression, diarrhoea and severe toxaemia;
however, this combination occurs in 50% or less of
affected horses. Fever of unknown origin may be
the only presenting sign. Diarrhoea may be mild,
of short duration or not evident in some cases.
Septicaemia and extraintestinal infection are of most
concern in foals. Sloughing of the intestinal mucosa
(Fig. 4.164) may be evident as the passing of casts in
the faeces.

Fig. 4.163 Small intestine and mesentery of a Clostridial diarrhoea
horse with disseminated intravascular coagulation The clinical presentation of CDI and C. perfringens-
secondary to colitis. associated diarrhoea is highly variable and non-
specific. Clinical presentation can range from mild
4.164 disease with only soft faeces, to peracute necrohaem-
orrhagic colitis with rapid progression to death.

Potomac horse fever
PHF can have a somewhat different clinical pro-
gression. Fever can be very high (up to 41.7°C
[107°F]). Usually, an initial episode of mild depres-
sion, anorexia and fever is produced. Moderate to
severe diarrhoea may ensue; however, diarrhoea only
occurs in approximately 60% of cases. Severe toxae-
mia and depression may accompany colic. Laminitis
may develop in 25–40% of cases and may be more
severe than would have been expected based on
Fig. 4.164 Intestinal mucosa of a horse with the severity of the intestinal and systemic disease.
salmonellosis. Note the mucosal casts detaching from Abortion may occur several months after resolution
the mucosal surface. of disease because of fetal infection.