Page 597 - Small Animal Internal Medicine, 6th Edition

CHAPTER 35 Hepatobiliary Diseases in the Cat 569

Neutrophilic Cholangitis Clinical Features
Neutrophilic cholangitis is also known as suppurative chol- Cats of all ages and breeds can be affected, but acute cholangi-
VetBooks.ir angitis, exudative cholangitis-cholangiohepatitis, and acute presents acutely (less than 1 month’s history), although it
tis is most often seen in young to middle-aged cats. It usually
cholangitis-cholangiohepatitis.
Pathogenesis and Etiology may be present longer. Cats typically have signs of biliary
stasis and sepsis with lethargy, pyrexia, and jaundice.
This process is believed to be caused by an ascending bacte-
rial infection originating in the small intestine. The most Diagnosis
common organism isolated is Escherichia coli, although Strep- Clinicopathologic and imaging findings overlap with those
tococcus spp., Klebsiella spp., Pseudomonas spp., Enterococ- in other diseases of the biliary tract, so a definitive diagno-
cus spp., Clostridium spp., and even occasionally Salmonella sis of neutrophilic cholangitis cannot be made simply from
spp. may be involved. Concurrent pancreatic and intestinal a characteristic history and clinicopathologic findings.
disease is common (see earlier). The result is a neutrophilic However, cats with this acute disease tend to have higher seg-
infiltrate in the lumen of the bile duct and often infiltra- mented and band neutrophil counts, ALT activities, and total
tion of the bile duct walls with neutrophils, and edema and bilirubin concentrations than cats with lymphocytic cholan-
neutrophils within the portal areas (Fig. 35.5). Occasion- gitis. Rather surprisingly, a recent study documented that
ally, an associated hepatic abscess may develop. Cholecystitis some cats with acute neutrophilic cholangitis had normal
(inflammation of the gallbladder) may occur concurrently, white blood cell counts and liver enzyme levels, and there
or the two conditions may occur separately. A more chronic was significant overlap in clinicopathologic values among
stage of neutrophilic cholangitis is also recognized; in these cats with acute neutrophilic cholangitis, chronic neutrophilic
cases there is a mixed inflammatory infiltrate in the portal cholangitis, and lymphocytic cholangitis. Therefore clinico-
areas consisting of neutrophils, lymphocytes, and plasma pathologic findings were neither sensitive nor specific for the
cells. Some of these cases are thought to represent more disease (Callahan Clark et al., 2011). Also, hepatic ultraso-
chronic, persistent infection of the biliary tract, although a nography is neither sensitive nor specific. Affected cats may
recent study using fluorescence in situ hybridization failed have an enlarged hyperechoic liver on ultrasonography and
to find more bacteria in these cases than in control cats may develop dilated biliary tracts more chronically, but cats
(Warren et al., 2011). There is significant overlap between with the acute disease usually have no dilation of the biliary
cats with chronic neutrophilic cholangitis and cats with lym- tract on ultrasonography, and the hepatic parenchyma may
phocytic cholangitis; the rest of this section describes only appear normal (Callahan Clark et al., 2011; Marolf et al.,
acute neutrophilic cholangitis. 2012). Pancreatic abnormalities are also commonly seen on
ultrasound in cats with neutrophilic cholangitis, supporting
the presence of triaditis in some affected cats.
An accurate diagnosis of neutrophilic cholangitis caused
by acute ascending infection requires cytology and culture
of bile. Histopathology of the liver alone is not enough in
this particular disease because in many cases the disease is
confined to the biliary tract, and changes on liver pathology
are mild and nonspecific. Samples of bile for bacterial culture
can be taken carefully from the gallbladder during laparot-
omy or laparoscopy or under ultrasonographic guidance.
There is a small but definite risk of bile leakage, particularly
if the gallbladder wall is devitalized and/or there is increased
intravesical pressure. In a study of six cats with neutrophilic
cholecystitis, one cat developed gallbladder rupture and bile
peritonitis after ultrasound-guided cholecystocentesis (Brain
et al., 2006). However, in one study of transcutaneous gall-
bladder aspiration in 12 normal cats (Savary-Bataille et al.,
2003) and in another study of 83 cats (Byfield et al., 2017),
there were no cases of gallbladder rupture. If the clinician
has a concern about the integrity of the gallbladder wall, it
FIG 35.5 might be safer to obtain a sample at laparotomy or laparos-
Photomicrograph of liver specimen from a cat with copy rather than under ultrasonographic guidance. In the
neutrophilic cholangitis. Note the neutrophilic and histiocytic latter case, a general anesthetic is strongly recommended to
inflammation in and around the bile ducts (large arrow).
Biliary ductular hyperplasia is also present (small arrow) prevent patient movement while the needle is in the gallblad-
(H&E stain Bar = 100·m). (Courtesy Pathology Department, der, which greatly increases the risk of bile leakage. Some
Queen's Veterinary School Hospital, University of clinicians place the needle in the gallbladder through the
Cambridge, Cambridge, England.) hepatic parenchyma to further reduce the risk of leakage.