Page 326 - Problem-Based Feline Medicine

318 PART 6 CAT WITH WEIGHT LOSS OR CHRONIC ILLNESS

Diffuse lymphosarcoma are best treated with com- Pathogenesis
bination chemotherapy.
Pancreatitis develops when there is activation of
● Lymphoblastic lymphosarcoma and lymphosarcoma
digestive enzymes within the pancreas, which results
affecting more than just the GI tract are best treated
in some degree of auto-digestion. While there are many
with combinations of cyclophosphamide, vincristine
possible causes of pancreatitis in cats, over 90% are
and prednisolone, ± doxorubicin, ± l-asparaginase
idiopathic.
(see page 676, for protocols and doses).
● Lymphocytic lymphosarcoma may respond more In cats, the most common forms of pancreatic disease
favorably to a combination of only prednisolone are chronic non-suppurative (lymphocytic/plasma-
(10 mg/cat/day PO) and chlorambucil (2–5 mg/m 2 cytic or, occasionally, eosinophilic) pancreatitis and
2
PO up to once every 48 h or 15 mg/m /day for 4 suppurative (neutrophilic) pancreatitis, while acute
days PO, every 3 weeks). septicemic pancreatitis and exocrine pancreatic insuffi-
ciency (EPI) are seen less frequently.
Prognosis It is the presence of exocrine pancreatic insuffi-
ciency that results in weight loss with a good, often
The prognosis is guarded. The best prognostic indica-
ravenous, appetite.
tors are response to therapy and the duration of the first
● Primary exocrine pancreatic insufficiency is
remission.
uncommon in cats. However, exocrine pancreatic
Response rates to chemotherapy range from 30–70%, insufficiency secondary to chronic, often episodic,
with median remissions of 4–23 months. pancreatitis is being recognized more frequently.
● In exocrine pancreatic insufficiency the lack of pan-
Being FeLV positive or having lymphoblastic lym-
creatic digestive enzymes leads to maldigestion and
phosarcoma are negative indicators, while having
malabsorption.
lymphocytic lymphosarcoma is a positive indicator.
● Lymphoblastic lymphosarcoma has a complete In cats, pancreatitis is often seen in association with
remission rate of 18%, and median survival time of idiopathic inflammatory bowel disease (IBD),
2.7 months. cholangitis/cholangiohepatitis complex, or both
● Lymphocytic lymphosarcoma has a complete remis- (termed “triaditis”).
sion rate 69%, median survival time 22.8 months. ● This association may occur because the pancreatic
duct in some cats enters the common bile duct
Prevention before it opens into the duodenum. In other cats, the
pancreatic and bile ducts enter the duodenum sepa-
Since it is not known what triggers lymphosarcoma to rately.
develop, it is not currently possible to prevent its ● When disease occurs in the small bowel it may
onset. However, since lymphocytic IBD has been seen ascend the common bile duct and from there affect
to progress to lymphosarcoma, it would appear sensible the pancreas and the rest of the biliary tree, or it may
to try to control lymphocytic IBD as well as possible, to ascend both ducts from their opening in the duode-
try to prevent its progression. num. For the same reason, disease of the biliary tree
or pancreas may affect the other two regions.
CHRONIC PANCREATITIS/EXOCRINE ● Regardless of which organ is affected first, the
PANCREATIC INSUFFICIENCY* other two organs tend to become involved as
inflammatory mediators, infectious agents, bile
and/or pancreatic secretions pass from one area to
Classical signs
another.
● Typically seen in middle-aged to older cats.
● History of episodic anorexia, lethargy, Clinical signs
vomiting and/or diarrhea.
● If also diabetic; polyuria and polydipsia. Chronic pancreatitis can occur in any sex or breed of
cat, and is typically seen in middle-aged or older cats.