Page 666 - Problem-Based Feline Medicine

658 PART 9 CAT WITH SIGNS OF GASTROINTESTINAL TRACT DISEASE

acute renal failure has developed before the cat presents Diagnosis
to the hospital.
A history of cancer chemotherapy and appropriate clin-
ical signs are often sufficient to make a presumptive
Prevention diagnosis. However, it is always important to bear in
mind that the vomiting could be unrelated to the
NSAIDs should be used cautiously in cats and cats that
drugs, and represent an additional problem associated
receive these drugs require frequent careful evaluation.
with the disease or a new problem that is unrelated to
Accidental exposure to medications not intended for the disease.
cats should be prevented.
Misoprostil (a prostaglandin agonist) has not been eval-
Differential diagnosis
uated in cats as a gastric protectant.
Vomiting may be due to the neoplastic disease itself.

TOXICITY (CHEMOTHERAPY DRUG-
INDUCED VOMITING) Treatment
Vomiting associated with cancer chemotherapy can be
Classical signs difficult to manage in some situations. The most effec-
tive anti-emetic drugs for this purpose are the drugs
● Anorexia.
that block the effects on the CRTZ, such as metoclo-
● Vomiting, with or without hematemesis.
pramide. In very severe cases, ondansetron or
● Abdominal pain.
dolasetron are other alternatives.
● Diarrhea, with or without melena.
In animals that have uncontrollable vomiting, the treat-
ment regimen may have to be altered to allow the cat to
Pathogenesis have reasonable quality of life.

Nausea and vomiting are frequent complications of
Prognosis
cancer chemotherapy drugs. There are many different
chemotherapeutic agents and they all vary in their Guarded, primarily because of the presence of cancer
effects; however, cisplatin, doxorubricin, vincristine requiring chemotherapy for treatment or control.
and methotrexate commonly cause gastrointestinal
side effects.
The cause of the vomiting may be due to direct stimu- ANESTHETIC AGENT (XYLAZINE)
lation of the CRTZ or toxicity to the gastrointestinal
tract by inhibiting the rapidly dividing stem cells that Classical signs
populate the GI epithelium. Vincristine does not have
● Lethargy, sedation.
direct cellular toxicity, but may induce ileus, which can
● Vomiting.
result in vomiting, diarrhea or both.
● Bradycardia.
● Hypotension.
Clinical signs

The most common GI signs observed with cancer
Pathogenesis
chemotherapy drugs are non-specific, and include
anorexia, vomiting, with or without hematemesis, Xylazine is an alpha-2 adrenergic antagonist seda-
abdominal pain due to bloating from ileus, diarrhea, tive-anesthetic that will induce emesis in cats within
pyrexia due to development of secondary infections, or minutes of administration due to direct effects on the
lethargy. CRTZ.