Exam 3 - Biliary Disease Flashcards
what are the functions of bile?
bile acids are essential for digestion/absorption of fats
elimination of lipophilic metabolic products & xenobiotics
what makes up the flow of bile through the biliary tract?
hepatocytes secrete bile & this drains into bile ductules/caniculi
intralobular ducts
interlobular ducts
hepatic ducts
common bile ducts
cystic duct
gallbladder
what is the function of the gallbladder?
stores & concentrates bile
bile is released after a meal in response to CCK, motilin, & vagal stimulation
what is the main anatomical difference in the biliary system between dogs & cats?
cats - major bile duct is a combo of the pancreatic duct & bile duct into the duodenum
dogs - separate openings for bile duct & pancreatic duct
cats more at risk for biliary tract infections/triaditis/etc
where are bile acids excreted from?
excreted in the bile
what is the cycle of bile acids?
bile acids are excreted in the bile - go through bacterial degradation & secondary bile acids
bile acids are reabsorbed from the ileum & enter portal circulation
bile acids are extracted by the liver for storage into the gallbladder & then re-excreted
cholesterol is used in hepatic bile acid synthesis in the liver where it is conjugated by the liver & then stored in the gallbladder
what are some common biliary disorders seen in dogs?
- gallbladder mucocele
- cholecystitis/cholangitis
- extrahepatic bile duct obstruction
- bile peritonitis
what is the common signalment of dogs affected by gallbladder mucoceles?
middle aged to older dogs
breeds - shelties, cocker spaniels, mini schnauzers, & border terriers
what are some risk factors for gallbladder mucocele formation in dogs?
hypothyroidism, hyperadrenocorticism
hyperlipidemia
gallbladder inflammation & hypomotility
imidacloprid?
what is the pathogenesis of gallbladder mucoceles?
cystic mucosal hyperplasia
progressive accumulation of mucus containing bile
post-hepatic icterus may occur if the mucocele extends into the common bile duct
secondary bacterial infections
distension of the gallbladder can lead to ischemic necrosis
GB rupture & bile peritonitis can occur
what biliary disease is this breed known for?
gallbladder mucocele - shelties
what clinical signs are associated with gallbladder mucoceles in dogs?
inconsistent clinical signs - some dogs may have none
anorexia, lethargy, vomiting, icterus, & some present acutely due to GB rupture
what is seen on serum biochemistry that is supportive of a gallbladder mucocele in a dog?
often increased ALP/ALT
sometimes increased bilirubin
how are gallbladder mucoceles diagnosed?
serum biochemistry
abdominal ultrasound - stellate pattern with non-gravity dependent bile, gallbladder wall thickening
T/F: an abdominal ultrasound is sensitive for detecting a ruptured gallbladder in a dog
false - not sensitive
you’re doing an abdominal ultrasound on an older dog with non-specific clinical signs and see this - what are you diagnosing?
gallbladder mucocele
when is medical management appropriate to use for a dog with a gallbladder mucocele?
dogs with no clinical signs or concerning lab/imaging findings
how is medical management used for a dog with a gallbladder mucocele?
treat any underlying disorders
low-fat diet
ursodeoxycholic acid & SAMe for cholestasis
+/- abx
repeat ultrasound every 1-3 months - may need to treat patient for months
T/F: surgical outcomes for gallbladder mucoceles are better for elective/prophylactic surgery than emergent surgery
true
what is the surgical correction used for gallbladder mucoceles? what should be done during this surgery?
cholecystectomy
ensure the patency of the biliary system by cannulating the duodenal papilla & flush it
histopathology of the liver & gallbladder
culture the bile, GB, & liver
T/F: cholecystitis/cholangitis is less common in dogs than cats
true
why may we see cholecystitis/cholangitis in a dog?
may be due to ascending bacteria from the gi tract
what clinical signs are seen in a dog with cholecystitis/cholangitis?
similar clinical signs to cats with neutrophilic cholangitis - often acute onset, icterus, & vomiting
what may be seen on lab findings of a dog with cholecystitis/cholangitis?
ALP/ALT commonly increased
bilirubin may be increased
+/- inflammatory leukogram
how is ultrasound used for diagnosing a dog with cholecystitis/cholangitis?
rule out physical obstruction of the biliary tract - from mucocele or pancreatitis
consider a cholecystocentesis for cytology & culture - risk of bile peritonitis if you do this
how is surgery used to diagnose a dog with cholecystitis/cholangitis?
abdominal exploratory - consider a cholecystectomy
check patency of the biliary tract
histopathology of the liver & gallbladder - required for definitive diagnosis!!!!
culture of liver, GB, bile, & any cholecystoliths
you do cytology of a cholecystocentesis from a dog with suspected cholecystitis/cholangitis and see this - what do you think?
septic bile
when is surgery indicated for cholecystitis/cholangitis in a dog?
cholecystectomy in addition to medical management
indicated when there is bile peritonitis, questionable GB wall integrity, or recurrent cases
what is the medical management used for a dog with cholecystitis/cholangitis?
4-6 weeks of antibiotics ideally based on c/s - amoxi/clav is a reasonable empiric choice
ursodeoxycholic acid
hard to clear a bacterial infection of the GB with antibiotics alone!!!
what are some common causes of extrahepatic bile duct obstructions in dogs?
- pancreatitis
- neoplasia of the biliary tract or pancreas
- obstructive gallbladder mucocele
what are some less common causes of extrahepatic bile duct obstructions in dogs?
- stricture of the bile duct
- diaphragmatic hernia
- obstructive cholelithiasis
- intestinal foreign body
what consequences are seen in dogs with an extrahepatic bile duct obstruction?
hydrophobic bile acids damage hepatocytes & cholangiocytes
progressive distension of the bile ducts
fat malabsorption - vitamin K deficiency
secondary infections
after 6 weeks or more, biliary cirrhosis may develop - portal hypertension & acquired portosystemic shunts
how are extrahepatic bile duct obstructions diagnosed?
usually ALP»_space; ALT with GGT often increased
cholesterol & bilirubin increased
abdominal ultrasound - distension of biliary tree & gallbladder, may need to be repeated
surgical explore may be needed for confirmation
what are you looking for on ultrasound in a dog you think has an extrahepatic bile duct obstruction?
distension of the biliary tree & gallbladder
what pathology is seen in this dog?
dilated common bile duct
what is the only condition that causes extrahepatic bile duct obstruction in dogs that you can appropriately manage medically?
pancreatitis
what conditions causing extrahepatic bile duct obstructions in dogs require surgical management?
obstructive gallbladder mucocele
stricture
diaphragmatic hernia
obstructive cholelithiasis
intestinal foreign body
how is bile peritonitis in dogs diagnosed?
exudate sometimes has bile crystals
effusion bilirubin»_space;»» serum bilirubin
^ it can be 1:1 ratio in dogs & still be a ruptured gallbladder
if you see gas present in the gallbladder, will you still poke it for a culture? why?
no!!!!! emphysematous cystitis, very bad no poke
if you diagnose a dog with bile peritonitis, what are you going to do in a very urgent manner?
surgery - especially if the bile is septic
what are some common biliary disorders seen in cats?
- feline cholangitis syndrome - neutrophilic, lymphocytic, & fluke-associated
- cholelithiasis
- cholecystitis
- ductal plate abnormalities - biliary cystadenomas & polycystic liver disease
is this a normal gallbladder in a cat?
yup - bilobed gallbladder
how is a dog definitively diagnosed with cholecystitis/cholangitis?
histopathology of the liver & gallbladder - done during surgery or other way I guess
what trematodes are involved in causing fluke-associated feline cholangitis? where do cats get them?
metorchis conjuctus & parametorhis complexus
cats get them from secondary hosts (reptiles & fish)
T/F: some cats with fluke-associated feline cholangitis may have no clinical signs
true
what is seen on this liver biopsy of a cat?
fluke!!!
what clinical signs may be seen in a cat with fluke-associated feline cholangitis?
weight loss, anorexia, vomiting, diarrhea, & icterus
how is fluke-associated feline cholangitis diagnosed?
fecals are hard because shedding of eggs is sporadic
diagnose on bile cytology or histology of the liver
how is fluke-associated feline cholangitis treated?
trial treatment with praziquantel (20 mg/kg PO every 8 hours for 3-5 days)
supportive care - short course of prednisolone, +/- ursodeoxycholic acid & prophylactic abx
when is a cholecystectomy indicated for a cat with cholecystitis?
bile peritonitis, question gallbladder wall integrity, or recurrent cases
T/F: clinical signs, diagnosis, & treatment for cholecystitis are similar to those for neutrophilic cholangitis
true
T/F: cholecystitis can be seen in conjunction with neutrophilic cholangitis or in isolation
true
what is seen on ultrasound in a cat with cholecystitis?
thickened gallbladder wall
what is the treatment of choice for biliary cystadenomas? what is it?
surgical excision
initially thought to be a benign growth - know we think of it more as a developmental/hereditary disease disease
are biliary cystoadenomas an incidental finding?
may be an incidental ultrasound finding in older cats - usually no clinical findings or lab changes
but you may notice a mass effect on abdominal palpation
why surgically remove biliary cystadenomas?
they can cause blockage of intrahepatic ducts
this is seen on an abdominal ultrasound of an older cat - what is this?
biliary cystadenoma
what cat breed is associated with the pictured pathology? what is it?
persians - polycystic liver disease
dilated common bile duct in a cat with extrahepatic bile duct obstruction
T/F: polycystic kidney disease is more common than polycystic liver disease in cats
true - sometimes the liver is infected in isolation or in conjunction with other organs
what is the range of clinical signs seen with polycystic liver disease in cats?
variable severity
mild lesions may not cause any signs
severe lesions - severe hepatomegaly, portal hypertension, & acquired shunts
why is percutaneous drainage not too useful for a cat with polycystic liver disease?
you can use it in severe cases but the fluid will come back
what pathology is seen on this dog’s gallbladder?
severe cholecystitis
T/F: surgery may be an option for clinically affected cats with polycystic liver disease
true
what are the goals of surgery of the biliary tract? what are the disadvantages of these surgeries?
- confirm the underlying disease process
- establish a patent biliary system
- minimize perioperative complications
relatively high morbidity/mortality rates - complex surgeries, so usually have to be referred
what is a cholecystectomy?
removing the gallbladder
what is likely the most common surgery performed on the biliary tract?
cholecystectomy
when is a choledochotomy used?
performed to remove a stone
what is the purpose of a cholecystotomy tube?
percutaneous drainage to provide temporary decompression - rarely done
what is a choledochoduodenostomy?
reattachment of the bile duct to a new location in the duodenum
what is a biliary-enteric anastomosis?
attaching the gallbladder to the small intestine for permanent drainage
what is the purpose of choledochal stenting?
provides temporary decompression for the gallbladder
