Page 653 - Problem-Based Feline Medicine

30 – THE CAT WITH SIGNS OF ACUTE VOMITING 645

Vomiting, diarrhea, hypersalivation and agitation Renal failure is a rare cause of acute vomiting in the
are the most common signs seen with exposure to per- cat.
methrins in cats. This is currently the most commonly
In cats that do vomit, the signs are generally chronic
reported toxicity in cats in the United States due to the
and associated with the effects of increased uremic tox-
accidental or inadvertent exposure of cats to the over-
ins causing nausea by their effects on the CRTZ and
the-counter flea products available for dogs.
also by associated hypergastrinemia and the direct
Severely affected cats may develop muscle tremors, effects on the stomach.
ataxia, excitation or seizures.
Cats with pyelonephritis may only have vague signs of
Organophosphate insecticides cause a combination of inappetence, fever or abdominal discomfort.
signs that include salivation, lacrimation, increased
defecation and urination due to the stimulation of
the parasympathetic nervous system. Other clinical Diagnosis
signs that may occur are vomiting, tremors, ataxia,
hyperthermia, dyspnea and seizures. Severely poisoned Palpation of the abdomen may reveal enlarged or
cats may die from the systemic effects of the toxin. painful kidneys (acute renal disease, pyelonephritis,
FIP, renal neoplasia or polycystic kidney disease), or
Diagnosis small, misshapen kidneys (chronic renal disease).

History of exposure to or ingestion of products con- Marked azotemia (elevated BUN and creatinine),
taining permethrin (most common) or pyrethroids. hyperphosphatemia, hyperkalemia and metabolic aci-
dosis in conjunction with isosthenuria (or impaired
There is generally no need for further diagnostic testing
urine-concentrating ability, e.g. urine specific gravity
since signs will abate with removal of pyrethrins or per-
< 1.030) and oliguria/anuria are classically associated
methrins from the skin or GI tract and supportive care.
with acute renal failure, while mild azotemia, hypo-
With organophosphates, if there is no known expo- kalemia, hyperphosphatemia, and metabolic acidosis
sure, but the toxicity is suspected based on clinical with isosthenuria and polyuria/polydipsia are found
signs, measurement of serum cholinesterase activity with chronic renal diseases.
levels may aid diagnosis. Levels less than 25% of nor-
Pyelonephritis and other inflammatory diseases of
mal are highly suggestive of OP toxicity.
the kidneys have fewer hematologic or biochemical
changes. Some cats may have an inflammatory leuko-
ACUTE RENAL gram (neutrophilia with or without a left shift), but
FAILURE/PYELONEPHRITIS* azotemia does not occur until late (renal failure
develops).
Classical signs
Urinalysis is very helpful in distinguishing infectious,
● Anorexia or decreased appetite. or inflammatory, renal diseases from other problems.
● Polyuria/polydipsia, and weight loss.
Pyelonephritis is difficult to diagnose definitively and
Occasional chronic vomiting, in advanced
is only confirmed by culture of organisms directly from
cats.
the kidney, either via ultrasound-guided pyelocentesis
● Cats with pyelonephritis may only have
or during a surgical exploratory.
vague signs of inappetence, fever or
abdominal discomfort. Other tests of renal function include intravenous pyelo-
grams or scintigraphic assessment of GFR, but these
See main reference on page 278 for details. are not universally available.

Clinical signs Ultrasound is also a useful tool for assessing renal
size and infrastructure, and is helping to assess the
Anorexia or decreased appetite, polyuria/polydipsia, patency of the ureters, presence of calculi, neoplasms,
and weight loss are the classic signs of renal disease. cysts or other abnormalities.