Page 739 - Problem-Based Feline Medicine

32 – THE CAT WITH SIGNS OF ACUTE SMALL BOWEL DIARRHEA 731

Classical signs—Cont’d Vomiting and anorexia are also occasionally
reported.
● Fecal characteristics may be normal, soft
and voluminous or watery diarrhea. The feces are typically pale, loose, voluminous, and
● Poor haircoat and greasy, flaky seborrhea they may be quite malodorous.
are also common. Cats often have a greasy, flaky haircoat due to the fat
malabsorption.

Pathogenesis Deficiencies of fat-soluble vitamins can result in a
bleeding disorder (vitamin K-responsive coagulopa-
Exocrine pancreatic insufficiency (EPI) is very rare in thy), which may present as excessive bleeding from
the cat compared to the dog. venepuncture sites or spontaneous hemorrhage
(nose bleeds, hematuria, melena, etc.).
The most common cause of EPI in the cat is chronic
pancreatitis.

A less common cause of EPI is infestation with the Diagnosis
feline pancreatic fluke, Eurytrema procyonis.
Results from routine hematology and chemistry pro-
Other, possible causes of EPI in cats include pancre- files will be normal in most cats. Occasionally, ele-
atic adenocarcinoma and congenital pancreatic acinar vations in hepatic enzymes or neutrophilia will be
hypoplasia or aplasia. observed.

Idiopathic pancreatic acinar atrophy, the most com- Routine abdominal radiography and ultrasonogra-
mon cause of EPI in dogs, has not been reported in cats. phy is usually normal, and is not diagnostic.
In humans with EPI caused by chronic pancreatitis, dia- Fecal proteolytic activity testing will reveal unde-
betes mellitus occurs concurrently. It is unknown tectable levels of enzymes, which is diagnostic for
whether cats with chronic pancreatitis and EPI will EPI, but the test is very labile, so false-positive tests
also progress to develop diabetes mellitus as well. occur to improper sample handling.
EPI is believed to develop when > 90% of the enzymes A recently validated radioimmunoassay for feline
of the exocrine pancreas are destroyed. These trypin-like immunoreactivity (fTLI) is available,
enzymes play an integral role in assimilating the major much like the TLI test available for use in dogs.
food components: proteins, lipids and carbohydrates.
Severely decreased fTLI concentrations are diag-
Pancreatic enzymes increase the efficiency of breakdown nostic for EPI in cats.
of macromolecules in the digestive tract and enhance the
All cats with EPI should have a serum cobalamin
transport mechanisms for sugars, amino acids and fatty
and folate assay, since many cats with EPI are cobal-
acids. Thus, food substances are inefficiently broken
amin deficient or have concurrent small bowel disease,
down and cannot be readily transported across the
causing folate levels to be low.
intestinal lumen without pancreatic enzymes.
Diarrhea occurs due to the presence of large quantities
of fats, protein and carbohydrates, which are osmotic. Differential diagnosis
Maldigestion of these important nutrients leads to The clinical signs are so non-specific that many other
weight loss and may also cause deficiencies of vita- diseases that cause polyphagia, weight loss and diar-
mins, fatty acids or other essential nutrients. rhea must be considered: hyperthyroidism, diabetes
mellitus, corticosteroid treatment or hyperadrenocorti-
cism, chronic renal failure, heart failure, liver disease,
Clinical signs
dental disease, neoplasia, and chronic intestinal dis-
The most common clinical signs are polyphagia, eases such as inflammatory bowel disease and ali-
diarrhea and weight loss. mentary lymphoma.