Page 755 - Problem-Based Feline Medicine

33 – THE CAT WITH SIGNS OF CHRONIC SMALL BOWEL DIARRHEA 747

The diarrhea may be mild, with soft to unformed feces In addition to liver histopathology, samples of hepatic
in cats with lymphocytic cholangitis, to severe, liquid tissue should also be submitted for aerobic and anaer-
diarrhea in cats with neutrophilic cholangitis. obic culture.

Differential diagnosis
Diagnosis
Cats that have vomiting, diarrhea, and weight loss in
The presence of icterus helps to narrow the differen-
addition to icterus, the list of differentials is narrowed
tials list to hepatic, pre-hepatic and post-hepatic
to pre-hepatic causes (hemolysis), hepatic causes
diseases.
(hepatic lipidosis, hepatic necrosis, hepatic failure,
The hemogram in cats with hepatic disease is often etc.), and post-hepatic causes (pancreatitis, neoplasia
abnormal (e.g. mild, non-regenerative anemia, with of stomach, pancreas, duodenum or bile duct, and com-
RBC morphology having schistocytes, leptocytes or mon bile duct obstruction).
target cells present), but the changes are not specific
In cats that are not icteric, the list of potential causes
for liver disease. However, it does help rule out pre-
broadens extensively to include the spectrum of meta-
hepatic causes of icterus.
bolic, neoplastic, toxic and infectious causes of both
Serum chemistry abnormalities may include elevated systemic and primary gastrointestinal origin.
liver enzyme activities (sometimes dramatically),
hyperbilirubinemia, hypocholesterolemia, hypoal-
buminemia, decreased BUN, and electrolyte alter-
Treatment
ations consistent with vomiting or dehydration, e.g.
hypokalemia, hypernatremia. Therapy for cats with cholangitis is largely support-
ive, but the histopathologic findings are crucial in
Bilirubinemia and bilirubinuria are both common.
determining severity, the type of inflammatory infil-
Serum bile acid assay (pre- and 2 hours post-prandial) trate (which is essential to choosing appropriate ther-
may show mild to moderate elevations. apy), and the overall prognosis for the disease.
Urine sulfated bile acids is a new test of hepatic func- Most cats with severe liver disease will require fluid
tion that may also become useful in the diagnosis of therapy to replace deficits, provide maintenance fluid
liver disease. support during the recovery period, and induce diuresis
to assist removal of hepatotoxins and prevent tubular
Coagulation function (platelet numbers and function,
sludging from bilirubinuria and casts.
and coagulation factors) should be evaluated since liver
disease often adversely affects these functions. The fluids should be isotonic, balanced electrolyte
solutions, but preferably not containing lactate which
Ultrasonography is the most useful imaging modal-
is not converted to bicarbonate in cats with liver failure
ity, because it can also be used to obtain fine-needle
and thus serves as an additional source of acid
aspirates or biopsies. However, needle biopsies are
(Ringers solution and Normosol-R are replacement
only accurate for diagnosis of cholangitis < 40% of
electrolyte solutions without lactate).
the time. In cats with cholangitis, the liver may be
normal, decreased or increased in size, but typically Vomiting should be controlled with a combination
will have a hyperechoic pattern due to the presence of of anti-emetic therapy (e.g. metoclopramide or
inflammatory infiltrates. dolasetron) and acid-blocking therapy (H antago-
2
nists such as famotidine, ranitidine or cimetidine),
Liver biopsies taken via surgical exploratory or
since cats with liver disease are prone to the develop-
laparoscopy are more accurate, and will also allow
ment of hypergastrinemic gastritis.
placement of a feeding tube (gastrostomy or jejunos-
tomy tube) during the procedure, which is essential for Diarrhea is rarely severe enough to require therapy and
any cat that has not eaten for 3–5 days. often resolves as the anorexia worsens.