Page 327 - Problem-Based Feline Medicine

17 – THE CAT WITH WEIGHT LOSS AND A GOOD APPETITE 319

Burmese cats in Great Britain may be predisposed to demonstrate undigested fat (Sudan III or IV stain) and
pancreatitis. starch (iodine stain), and fat absorption tests.
History and clinical signs of chronic pancreatitis tend Abdominal radiographs are usually unremarkable.
to be very variable and non-specific.
Ultrasound examination may reveal pancreatic
They usually include episodes of anorexia or variable enlargement, irregularity or heterogeneity, evidence of
appetite, with or without vomiting and/or diarrhea, peripancreatic fat necrosis, enlargement of mesenteric
weight loss and/or possible abdominal pain. lymph nodes, and/or evidence of post-hepatic biliary
obstruction (enlarged gall bladder, thickened bile or
Once exocrine pancreatic insufficiency develops the
tortuous common bile duct).
cat is usually thin, has a greasy coat and produces
large quantities of voluminous, fatty, foul-smelling Evaluation of serum trypsin-like immunoreactivity
feces or has severe diarrhea. (TLI) may be helpful.
● The species-specific assay must be performed on a
Cats with chronic pancreatitis may also develop
fasted serum sample.
episodic or persistent diabetes mellitus, which is seen
● Serum TLI may be increase with pancreatitis and
as polyuria and polydipsia.
decrease with exocrine pancreatic insufficiency.
When both exocrine pancreatic insufficiency and dia- ● While it consistently diagnoses exocrine pancreatic
betes occur concurrently the polyphagia can be pro- insufficiency, it often fails to confirm pancreatitis,
found. possibly because chronic inflammation has reduced
Physical examination is often unremarkable, but may the overall ability of the pancreas to produce TLI.
reveal anterior abdominal discomfort, a palpably irreg- Evaluation of serum pancreatic lipase immunoreac-
ular and enlarged pancreas, or hepatomegaly associated tivity (PLI) may be helpful.
with cholangitis/cholangiohepatitis complex. ● The species-specific assay must be performed on a
fasted serum sample.
Diagnosis
● Serum PLI may increase with pancreatitis and
Chronic pancreatitis is very difficult to diagnose. appears to be more sensitive than TLI.
Hematology and serum biochemistry may reveal non- A therapeutic trial with replacement pancreatic
specific changes. enzymes may be considered (see under treatment).
● Hematology may show neutrophilia, neutropenia ● Providing that any associated IBD and/or cholangi-
(associated with sequestration during acute exacer- tis/cholangiohepatitis complex has been addressed,
bation), monocytosis and/or a mild non-regenera- the response to treatment may be dramatic. However,
tive anemia. a positive response is not diagnostic of chronic pan-
● Serum biochemistry may show hyperglobuline- creatitis and/or exocrine pancreatic insufficiency.
mia, bilirubinemia and raised liver enzymes
(depending on the degree of associated cholangi- Pancreatic biopsy is required to confirm a diagnosis
tis/cholangiohepatitis complex), and/or hyper- of pancreatitis.
cholesterolemia, hypertriglyceridemia and ● Because triaditis is common, it is advisable to col-
hyperglycemia (often associated with concurrent lect liver and intestinal biopsies at the same time,
diabetes). Hypocalcemia may be associated with and send part of the liver biopsy and a sample of
severe disease. bile for culture.
● Serum amylase and lipase tests are rarely useful
in the diagnosis of pancreatitis in cats, although a Differential diagnosis
raised lipase level may be seen occasionally.
These include most of the other causes of weight loss
Serum cobalamin and folate levels are usually
with a good appetite. However, since cats with chronic
decreased.
pancreatitis and exocrine pancreatic insufficiency usu-
A number of older tests are very unreliable and are now ally develop diarrhea and/or vomiting, other causes of
rarely used. These include staining fecal smears to enteropathy, IBD, cholangiohepatitis, alimentary