Page 642 - Problem-Based Feline Medicine

634 PART 9 CAT WITH SIGNS OF GASTROINTESTINAL TRACT DISEASE

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● Non-steroidal anti-inflammatory drug (NSAID) toxicity (p 656)
Vomiting associated with non-steroidal anti-inflammatory drugs (aspirin, ibuprofen) is usually
associated with acute gastritis and erosions that occur secondary to the anti-prostaglandin effects
on the stomach. Ibuprofen will also cause acute renal failure. Acetaminophen does not induce gas-
tritis but vomiting has been observed in cats due to the hepatotoxicity. Other clinical signs that
occur more frequently and are more important include facial edema, pruritus, salivation, tachyp-
nea, depression and cyanosis (due to methemoglobinemia).

● Arsenic poisoning (p 659)
Arsenic is found in herbicides, insecticides, wood preservatives and blood parasiticides. Initial
clinical signs include vomiting, diarrhea, anorexia and depression. This is followed by hepatic and
renal failure.

INTRODUCTION WHERE?
Vomiting may result from gastrointestinal disease or
MECHANISM? extra-intestinal tract diseases.
Vomiting occurs when the vomiting center in the Acute vomiting associated with extra-intestinal dis-
medulla is stimulated, which can occur by several eases may be due to:
mechanisms: ● CNS disease (e.g. encephalitis or vestibular disease).
● Effect of blood-borne toxins or drugs. ● Pancreatitis.
● Afferent impulses from the cerebral cortex, ● Hepatobiliary disease.
chemoreceptor trigger zone (CRTZ), the ● Renal disease causing acute or chronic renal failure.
vestibular apparatus, or receptors in the phar- ● Metabolic or endocrine diseases including
ynx or abdominal viscera. ketoacidotic diabetes mellitus and hypercalcemia.
● Systemic illness or infection, e.g. septicemia,
The chemoreceptor trigger zone (CRTZ) is stimulated
pyometra.
by:
● Blood-borne toxins, including uremic toxins or Primary gastrointestinal diseases that cause acute
drugs. vomiting involve the stomach or small intestine:
● Parasites, e.g. Physaloptera, Ollulanus, etc.
Vomiting is an active process that must be distin-
● Infectious diseases, e.g. Salmonella, Helicobacter.
guished from regurgitation.
● Inflammatory diseases, e.g. IBD.
Vomiting in cats is associated with abdominal muscle ● Neoplasia.
contraction, and signs of considerable muscular ● Mechanical, e.g. foreign body obstruction, intus-
effort and anxiety prior to the event. susception, motility disturbances.
● Dietary disturbances, e.g. indiscretion or food
Vomitus may consist of undigested food material (if
intolerance.
swallowed whole), partly digested or even liquid, and
may be clear, yellow (bile stained) or brown (food col- Vomiting is rarely associated with colonic disease,
ored). except when toxins associated with fecal retention affect
the vomiting center and chemoreceptor trigger zone.
Vomitus is not typically tubular in form, nor does it
contain large amounts of white frothy material.
WHAT?
The pH of vomitus is usually acidic (pH < 4), but may
be neutral (pH 7) if duodenal content is present (bile The most common causes of acute vomiting are:
reflux). mechanical obstructions (including foreign bodies),