Page 778 - Problem-Based Feline Medicine

770 PART 9 CAT WITH SIGNS OF GASTROINTESTINAL TRACT DISEASE

commercial diets are recommended because they are Pathogenesis
nutritionally complete and balanced.
Disease is induced by changes in the diet, antibiotic
Low-residue diets are usually more appropriate for therapy, ingestion of carrion or contaminated
cats with small bowel IBD, but in some cases, provid- food, or stress that results in alteration of the nor-
ing a diet that will result in reduced colonic residue is mal colonic bacterial flora and changes in colonic
more effective. motility.

The key to choosing a diet is recognizing that not all These changes allow pathogens normally present
cats respond the same and a willingness to try a differ- (Clostridia, Campylobacter, E. coli, etc.) to overgrow
ent approach is necessary. or begin to secrete toxins that change permeability,
● Initial pharmacologic therapy includes pred- increase secretions, or cause release of inflammatory
nisolone (2–4 mg/kg q 12 h) and metronidazole mediators.
(10–15 mg/kg q 12 h).
Campylobacter is much more common in young cats,
● In cases that do not respond to these drugs,
while clostridial overgrowth is more commonly seen
tylosin (5–100 mg/kg q 12 h), sulfasalazine (11–22
in adults.
mg/kg q 12–24 h) or olsalazine (no dose established
in cats, but 5–10 mg/kg may be reasonable), may be
added.
● Chlorambucil and azathioprine have been used in Clinical signs
refractory cases of small bowel IBD, but usually
Hematochezia and large bowel diarrhea that is
are not required in colonic IBD. Cats are particu-
mucoid, soft and self-limiting is common.
larly sensitive to the myelosuppressive side effects
of azathioprine. Diarrhea may become more liquid with time and
severity, and is more common with E. coli infections.
Most cats will respond to a combination of dietary
and prednisolone or metronidazole therapy and Vomiting may occur, but is uncommon.
eventually can be maintained with dietary management
Anorexia or lethargy are variably present, depend-
alone.
ing on the severity.
Prognosis Fever and other signs of infectious disease rarely
occur with infectious colonic diseases.
The prognosis for complete remission is only guarded
Weight loss is uncommon due to the acute nature of
to fair.
the condition.
However, most cats with colonic IBD can be success-
Historical information is very important in estab-
fully managed with a combination of dietary and
lishing the presumptive diagnosis.
pharmacologic therapy, and thus, the prognosis for
control is very good.

INFECTIOUS COLITIS* (CLOSTRIDIUM Diagnosis
SPP., E. COLI, CAMPYLOBACTER SPP.) A definitive diagnosis is difficult, because identification
of these organisms in feces is not necessarily abnormal.
Classical signs ● Clostridium perfringens enterotoxicosis is best
diagnosed by positively identifying the presence
● Diarrhea ranges from soft, mucoid blood-
of enterotoxin in the feces (ELISA or RPLA
streaked feces to liquid diarrhea (more
assays are commercially available). Note: these
characteristic of small bowel disease).
assays have not been evaluated in cats, but the
● Other signs may include vomiting, anorexia
ELISA assay appears to be more specific in dogs.
and lethargy.
A positive enterotoxin test determined by ELISA