Page 598 - Small Animal Internal Medicine, 6th Edition

570 PART IV Hepatobiliary and Exocrine Pancreatic Disorders

The cat should be monitored carefully for any leakage of bile of clinical and histologic presentations suggests more than
after the procedure; any suspicion of leakage and bile peri- one cause. Some researchers have suggested an immune-
VetBooks.ir tonitis warrants surgery. Cytology of bile usually shows bac- mediated etiology, but the disease does not resolve with
immunosuppressive medication. Other studies have sug-
teria and neutrophils, and culture and sensitivity tests should
gested possible infectious etiologies, such as Helicobacter or
be performed.
Bartonella spp. (Boomkens et al., 2004; Greiter-Wilke et al.,
Treatment and Prognosis 2006; Kordick et al., 1999), although recent work has not
Cats should be treated for 4 to 6 weeks with an appropriate supported infectious causes (Warren et al., 2011). However,
antibiotic on the basis of the results of culture and sensitiv- the use of immunosuppressive medication in all these cases
ity tests. Amoxicillin is a good initial choice at a dose of 15 is subject to question.
to 20 mg/kg PO q8h. Ursodeoxycholic acid may be given
as an additional choleretic and antiinflammatory agent at Clinical Features
a dose of 15 mg/kg PO q24h, although there are no studies Cats with lymphocytic cholangitis were previously reported
demonstrating its benefit in cats with neutrophilic cholan- to be typically young to middle-aged, and Persians appeared
gitis. Septic or extremely sick cats may require hospitaliza- to be overrepresented, but recent studies report it in older
tion for IV fluid and IV antibiotic administration during the cats with no obvious breed predisposition (Callahan Clark
initial stages of therapy. Careful attention should be paid to et al., 2011; Warren et al., 2011). Affected cats tend to have
feeding anorexic cats to prevent the concurrent develop- a long history (months to years) of waxing and waning low-
ment of hepatic lipidosis, which was found in one third of grade illness. Many become jaundiced, and they often lose
the cats with cholangitis in a recent study (Callahan Clark weight and have intermittent anorexia and lethargy, but they
et al., 2011); a high-protein diet designed for critical care are less likely to be pyrexic than cats with neutrophilic chol-
use, as outlined in the lipidosis section, is more appropriate angitis. About one third of cats may also present with a high-
for these animals than a protein-restricted liver diet. The protein ascites, reportedly most commonly in the United
prognosis is generally good, and these cats usually recover Kingdom. This makes differentiation from feline infectious
completely provided they are treated early and appropri- peritonitis (FIP) important. Ultimately, the differentiation in
ately. It is thought that some cases of the more chronic form these cats can be made only on histopathology.
of neutrophilic cholangitis may represent long-term persis-
tence of a low-grade infection in untreated or only partially Diagnosis
treated cats. Diagnosis in these cases relies ultimately on hepatic histopa-
thology, although ultrasonographic and clinicopathologic
Lymphocytic Cholangitis findings can support a presumptive clinical diagnosis.
Lymphocytic cholangitis is also termed lymphocytic cholan- Increases in liver enzyme levels are mild to moderate and
giohepatitis, lymphocytic portal hepatitis, and nonsuppurative tend to be less marked than in cats with neutrophilic chol-
cholangitis. Some cases of chronic neutrophilic cholangitis as angitis. Peripheral blood neutrophilia is less common than
defined by the WSAVA may also overlap with lymphocytic in cats with the acute disease but may be present. A particu-
cholangitis. lar feature of most cats with lymphocytic cholangitis is an
increase in γ-globulin concentration, which again may cause
Pathogenesis and Etiology confusion with FIP. However, some cats have normal white
Lymphocytic cholangitis is a slowly progressive chronic blood cell counts and liver enzyme levels, so these findings
disease characterized by infiltration of the portal areas of the are neither sensitive nor specific (Callahan Clark et al.,
liver with small lymphocytes. Occasionally, plasma cells and 2011). Radiographic signs are also nonspecific; there may be
eosinophils can be seen. The presence of neutrophils might hepatomegaly (which is often caused by enlargement of the
change the name of the disease to chronic neutrophilic chol- larger bile ducts) and in some cases abdominal effusion but
angitis, but some authors include a predominantly lympho- radiographs are often normal (Fig. 35.6). Ultrasonography is
cytic disease with a small number of neutrophils in the more helpful and reveals dilation of the biliary tract in some
lymphocytic chronic cholangitis category. Histologic changes patients (see Fig. 34.11). The common bile duct typically
vary among cases, probably reflecting a variety of as yet appears dilated, and there may be dilation of the gallbladder
unknown etiologies. In the largest study on the histology of and sludge in it. The main differential diagnosis for these cats
the disease (Warren et al., 2011), many cats had biliary is EBDO; the ultrasonographer should attempt to rule this
hyperplasia and peribiliary fibrosis, but a small number of out by carefully imaging the surrounding pancreas, small
cases showed ductopenia (loss of bile ducts). The lymphocyte intestine, and mesentery, although it can be difficult to rule
infiltrate was predominantly of T cells, but portal B-cell out EBDO completely particularly if it is caused by an echo-
aggregates seemed to be a particular feature of the disease. lucent lesion or sphincter of Oddi spasm.
Bile duct targeting by inflammatory cells was common. In It is very important to evaluate a hemostasis profile before
severe cases the main differential diagnosis on histology is performing a liver biopsy in view of how commonly coagula-
lymphoma, and in some cases, differentiating the two dis- tion times are prolonged in cats with liver disease. Vitamin
eases can be difficult. The cause is unknown, and the variety K should be given before the biopsy (0.5 mg/kg of vitamin