Diseases of the Gallbladder and Extrahepatic Biliary System

Question 1

What’s the major difference between dogs and cats regarding bile duct entrance into the duodenum?

Answer 1

In dogs: the common bile duct joins with the minor pancreatic duct but exits separately
In cats: the common bile duct fuses with the major pancreatic duct and enters the duodenum together

Question 2

Which breeds are predisposed to gallbladder stone (cholelithiasis)?

Answer 2

mini Schnauzer and mini Poodle

Question 3

What’s a difference in gallbladder stone composition between dogs and cats?

Answer 3

Calcium stone are rare in dogs as they can absorb free calcium in the bile.
Cats can have calcium based stones

Question 4

What’s the cause of gallbladder stones?

Answer 4

May be due to increased viscosity of the bile

Question 5

What’s the clinical signs of gallbladder stone?

Answer 5

most patients are asymptomatic; the stones can lead to rupture –> bile peritonitis
- vomiting
- anorexia
- icterus
- abdominal pain

Question 6

What are some common bloodwork abnormalities for gallbladder stone?

Answer 6

CBC:
- anemia of chronic disease
- neutrophilia, left shift with rupture
Biochem
- mild to moderate elevation in ALP, GGT, bilirubin
- hyperbilirubinemia precedes jaundice
- any ALP elevation in the cat = significant
- hypercholesterolemia becomes significant with obstruction
- hypoalbuminemia and hypoglycemia may be noted with sepsis and endotoxemia

Question 7

What’s the imaging modality of choice for diagnosing gallbladder stones?

Answer 7

ultrasound!
- can assess for wall thickening and fluids
- cats: common bile duct >5mm = extrahepatic biliary obstruction

Question 8

What’s the treatment for gallbladder stone?

Answer 8

medical dissolution rarely work – supportive therapy until it passes or surgery for more severe cases
cholecystectomies and choledochotomies

Question 9

Which type of biliary stenting is more permanent?

Answer 9

self-expanding metallic stents.
- plastic ones are only good for weeks to months

Question 10

What’s the role of bacteria in feline cholecystitis?

Answer 10

often considered secondary to inflammation

Question 11

What are some clinical signs associated with cholecystitis?

Answer 11

mild cases = asymptomatic
moderate-severe case = abdominal pain, anorexia, vomiting, pyrexia
-jaundice = variable
- chronic cases = more difficult to detect as c/s are intermittent

Question 12

How is cholecystitis diagnosed?

Answer 12

Ultrasound = gold standard
- bloodwork would be consistent with cholestasis: elevation in ALP, ALT, total bilirubin (esp in cats)

Question 13

What’s the characteristic of biliary effusion?

Answer 13

should be greenish fluid - bile
- if the bilirubin is >2x serum, then the GB has ruptured
- extra- and intra-cellular bacteria is common

Question 14

How is cholecystitis treated?

Answer 14

Medical: analgesics, IV fluids, antibiotics
- E coli, enterococcus spp, bacteroides, streptococcus, clostridium, helicobacter = most common
- ciprofloxacin and aminoglycosides
- need to be on antibiotics min 1month
- Severe cases or with peritonitis - cholecystectomy is preferred

Question 15

How is emphysematous cholecystitis treated?

Answer 15

Surgery! high risk of rupture
antibiotic choice: fluoroquinolone, metronidazole, or chloramphenicol

Question 16

In which species (cats or dogs) is biliary cystadenoma more common? where?

Answer 16

cats! mostly intrahepatic. rare in the dog
malignant transformation possible.

Question 17

How is biliary cystadenoma treated?

Answer 17

They are typically incidental findings in older male cats
- surgery can be done if causing spacy occupying issues

Question 18

Which tumour is the most common hepatobiliary carcinoma in the cat?

Answer 18

biliary carcinoma! it’s the 2nd most common in the dog

Question 19

What are the most common clinical signs associated with parasites of the biliary system?

Answer 19

weight loss, vomiting, anorexia

Question 20

What’s the most reliable method of confirming parasitic infection in the biliary system?

Answer 20

fecal sedimentation

Question 21

What’s the treatment for parasitic infection in the biliary system?

Answer 21

usually praziquantel
- should consider pretreatment with prednisone and anti-histamine in case of high parasitic load to minimize inflammatory response
- surgery may be indicated for obstructive cases

Question 22

What’s the pathophysiology for gallbladder mucocele?

Answer 22

persistent bile-laden semisolid to immobile sediment in the gallbladder leading to stretching and pressure necrosis of the gallbladder wall
- shelties and mini Schnauzer

Question 23

What endocrine diseases could lead to increased risk of gallbladder mucocele?

Answer 23

Hyperadrenocorticism
- increased steroids –> increases unconjugated bile acids –> hydrophobic –> injury of biliary epithelium
Hypothyroidism
- inability for the sphincter of Oddi to relax, altered hepatic cholesterol metabolism, diminished bile secretion –> mucin solidification

Question 24

What’s the predominate cause of gallbladder mucocele in the cat?

Answer 24

biliary stasis

Question 25

what are some clinical signs of gallbladder mucocele?

Answer 25

lethargy, anorexia, vomiting, abdominal pain
- fever if there is peritonitis or bacterial cholecystitis
- 40% = icterus

Question 26

What’s the gold standard for diagnosing gallbladder mucocele?

Answer 26

ultrasound! mucin = hypoechoic
blood work changes would be of typical cholestasis –> ALP. Can also have increased in ALT, GGT, and bilirubin
- marked elevation in cholesterol = biliary obstruction