Chapter 289: Diseases of the Gallbladder and Extrahepatic Biliary System

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Questions and Answers

Where is the gallbladder located?

Between the right medial and quadrate liver lobes (correct)

Between the left medial and quadrate liver lobes

Under the right kidney

Above the pancreas

What is the function of bile in the digestive system?

To break down proteins

To increase stomach acid production

To emulsify fats (correct)

To absorb carbohydrates

Which breed of dog is predisposed to cholelithiasis?

Miniature Schnauzer (correct)

German Shepherd

Labrador Retriever

Golden Retriever

What is the term for stones in the common bile duct?

Choledocholithiasis Signup and view all the answers

What is the diagnostic modality of choice for bile duct obstruction?

Ultrasound Signup and view all the answers

What is the term for the muscle that controls the flow of bile into the duodenum?

Sphincter of Oddi Signup and view all the answers

In cats, what is the indication of bile duct obstruction based on ultrasound?

Dilated common bile duct > 5 mm Signup and view all the answers

What is often asymptomatic in animals with choleliths or choledocholiths?

Clinical symptoms Signup and view all the answers

What is the order of dilatation of the bile ducts in cases of bile duct obstruction?

Common bile duct, then extrahepatic ducts, then intrahepatic ducts Signup and view all the answers

What is the primary goal of biliary stenting?

To facilitate patency and drainage of the biliary tree Signup and view all the answers

What is the most common malignant, primary feline hepatobiliary tumor?

Biliary carcinomas (cholangiocarcinomas) Signup and view all the answers

What is the typical duration of antibiotic treatment for cholecystitis?

A minimum of one month Signup and view all the answers

What is the best diagnostic tool for emphysematous cholecystitis?

CT scan Signup and view all the answers

What is the most common organism isolated in cases of cholecystitis?

E. coli Signup and view all the answers

What is the indication for surgical intervention in cases of emphysematous cholecystitis?

To prevent gallbladder rupture and septic peritonitis Signup and view all the answers

What is the most common location of biliary cystadenomas?

Intrahepatic bile ducts Signup and view all the answers

What is the significance of a gallbladder wall thickness > 1.0 mm in cats?

It represents gallbladder pathology Signup and view all the answers

What is the role of cholecystocentesis in the diagnosis and treatment of cholecystitis?

It is used to diagnose and treat cholecystitis Signup and view all the answers

What is the characteristic echographic finding in a mature gallbladder mucocele?

A hypoechoic to anechoic rim Signup and view all the answers

What is often located centrally and is immobile in a gallbladder mucocele?

Biliary sludge Signup and view all the answers

What is the primary treatment for many patients with a gallbladder mucocele?

Surgical correction with cholecystectomy Signup and view all the answers

What type of bacterial infections are common in patients with gallbladder mucoceles?

Both aerobic and anaerobic bacterial infections Signup and view all the answers

What medication is used to alter the microenvironment of the gallbladder and increase bile flow?

Ursodiol Signup and view all the answers

What is the ideal duration of antibiotic therapy for gallbladder mucoceles?

4 to 8 weeks Signup and view all the answers

What type of diet is likely beneficial for patients with gallbladder mucoceles?

Low-fat diet Signup and view all the answers

What is characterized by cystic mucinous hyperplasia of the gallbladder mucosa?

Gallbladder mucocele Signup and view all the answers

Which breed is at increased risk for developing a specific type of tumor?

Labradors Signup and view all the answers

What is the primary mechanism by which platynosomum species cause disease in cats?

Induction of bacterial cholangitis Signup and view all the answers

What is the term for the semisolid to immobile mucoid material that accumulates within the gallbladder?

Gallbladder mucocele Signup and view all the answers

Which factor is known to increase the risk of developing a gallbladder mucocele?

All of the above Signup and view all the answers

What is the typical appearance of an immature mucocele on ultrasound?

Hyperechoic biliary sludge with fracture lines Signup and view all the answers

What is the most common enzyme elevation seen in patients with gallbladder mucoceles?

ALP Signup and view all the answers

What is the typical clinical presentation of patients with gallbladder mucoceles?

Any of the above Signup and view all the answers

What is the primary complication of gallbladder mucoceles?

All of the above Signup and view all the answers

What is the treatment for platynosomum species in cats?

Praziquantel and ursodiol Signup and view all the answers

What is the breed most commonly associated with the development of gallbladder mucoceles?

Shetland Sheepdogs Signup and view all the answers

Study Notes

Gallbladder Anatomy

Gallbladder sits between right medial and quadrate liver lobes
Bile formed in hepatocyte and actively secreted into bile canaliculi
Bile flows into intralobular ducts, then lobar ducts, then left and right hepatic ducts
Hepatic ducts give rise to cystic duct, which travels toward the gallbladder
Cystic duct separates hepatic ducts from more distal common bile duct

Bile Composition and Function

Bile composed of cholesterol, lecithin, phospholipids, bile salts
Bile emulsifies fats
Gallbladder contraction releases bile into common bile duct, which enters duodenum through sphincter of Oddi
In dogs, common bile duct joins minor pancreatic duct and both empty at major duodenal papilla
In cats, common bile duct fuses with major pancreatic duct before entering duodenum

Cholelithiasis and Choledocholithiasis

Older female dogs predisposed, especially Miniature Schnauzer and Miniature Poodle breeds
Cholesterol, bilirubin, and mixed stones common in dogs
Feline choleliths composed of cholesterol, bilirubin, or calcium salts
Abnormalities promoting cholelith formation include gallbladder dyskinesia, hypercholesterolemia, hypertriglyceridemia, hyperbilirubinemia, endocrine disease
Choledocholiths are stones in common bile duct specifically
Often animals are asymptomatic; in other cases, there may be obstruction of common bile duct and/or biliary rupture with bile peritonitis

Biliary Stenting

Choledochal stenting for treatment of extrahepatic biliary duct obstruction
Plastic (polyurethane) stents facilitate patency and drainage of biliary tree; dislodge on their own or can be removed endoscopically
Self-expanding metallic stents more permanent, for treatment of recurrent disease or malignancy
Endoscopic retrograde cholangiopancreatography uses combo of endoscopy and fluoroscopy to evaluate biliary tree

Cholecystitis

Inflammatory conditions of the gallbladder
Predisposing factors include bile stasis, gallbladder mucocele, ascending bacterial or parasitic infection, neoplasia
In cats, bacterial infection thought to be secondary to inflammation rather than inciting cause
May be acute or chronic, mild or severe
Most clinicopathologic changes consistent with cholestasis or posthepatic biliary disease
Ultrasound reliably demonstrates gallbladder sediment, thickened gallbladder wall, choleliths, and evidence of extrahepatic bile duct obstruction

Emphysematous Cholecystitis

Rare manifestation of acute cholecystitis complicated by gas-producing organisms
Gas accumulates in lumen, wall, or pericholecystic tissues
Radiographically, disease characterized by spherical to ovoid gas opacity superimposed over hepatic silhouette
Anaerobes are most commonly isolated, including E. coli and Clostridium perfringens

Biliary Neoplasia

Biliary cystadenomas occur regularly in older cats and rarely in dogs
Most commonly from intrahepatic bile ducts
Biliary carcinomas (cholangiocarcinomas) most common malignant, primary feline hepatobiliary tumor, second most common in dogs
Labradors at increased risk
Locally invasive tumors with high likelihood of metastasis at time of diagnosis

Parasitic Disease of the Biliary System

Some species of flukes infect the hepatobiliary tree of cats (Platynosomum species)
Causes bacterial cholangitis, cholangiohepatitis, ductal fibrosis, EHBDO, and liver failure
Elevated liver enzymes and hyperbilirubinemia common
Ultrasound may show ductal dilation, hepatic cysts, biliary obstruction

Gallbladder Mucocele

Defined as presence of bile-laden semisolid to immobile mucoid material within the gallbladder
Predisposing factors include dyslipidemias, dysmotility of the gallbladder, endocrine disease, and exogenous steroid administration
Breed predispositions include Shetland Sheepdogs, Cocker Spaniels, and Miniature Schnauzers
Complications include extrahepatic bile duct obstruction, cholecystitis, necrotizing cholecystitis, bile peritonitis, and pancreatitis
Proposed etiologies include hyperadrenocorticism, exogenous steroids, and hypothyroidism

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Description

This quiz covers the anatomy and function of the gallbladder and extrahepatic biliary system, including the liver, bile ducts, and gallbladder. It includes questions on the structure and function of these organs and their relationship to the digestive system.