Biliary Tract

Question 1

Enterohepatic circulation

Answer 1

bilirubin –> colon bacteria –> urobilinogen –>

1. Stercobilin - stool
2. reabsorbed into bile –> urobilinin - urine

Question 2

Bile composition

Answer 2

Cholesterol, bilirubin (conjugated), phospholipids, electrolytes

Bile salts:
Na+ + bile acid - oxidized cholesterol w/ CYP450

bile acid:
Cholic acid, deoxycholic acid, Chenodeoxycholic acid
conjugated to:
Taurine --> taurocholic acid
or Glycine --> glycocholic acid

Question 3

Function of bile

Answer 3

digestion and absorption of lipids
excretion of cholesterol and bilirubin
copper excretion
bactericidal activity - kill bacteria ingested w/ food

Question 4

Primary sclerosing cholangitis (PSC)

Answer 4

concentric fibrosis of bile ducts –> narrowing

ERCP: stricturing and dilated “Beads on a string”

Men, 40 yo
80% +pANCA

Assoc w/ UC and cholangiocarcinoma

Question 5

Primary biliary cholangitis (PBC)

Answer 5

Autoimmune

T cells attack bile ductules in liver parenchyma

Granulomas
Cirrhosis (late)

Middle aged women

+AMA (antimitochondrial Ab)

Tx: ursodiol (ursodeoxycholic acid)

• bile acid decreases synthesis of cholesterol
• -> change in bile composition
• delays progression of PBC, improves survival
• slows, not reparative

liver transplant

Question 6

Secondary biliary cirrhosis

Answer 6

cirrhosis from biliary obstruction
secondary to extrahepatic process blocking biliary outflow
-gall stones, biliary stricture, pancreatitis
–> stasis of bile, ascending cholangitis
–> cirrhosis and fibrosis

Question 7

Symptoms of biliary tree obstruction

Answer 7

Jaundice, pruritis
dark urine
light acholic stools
high alk phos
high direct bilirubin

Question 8

Differential diagnosis of unconjugated hyperbilirubinemias

Answer 8

Increased bilirubin production

• hemolytic anemia
• sickle cell disease
• hematoma breakdown

Impaired bilirubin uptake and storage

• viral hepatitis
• Drugs - rifampin

Decreased UDP-GT activity

• Gilbert syndrome
• Crigler Najjar 1 and 2
• Neonatal physiologic jaundice

Question 9

Differential diagnosis of conjugated hyperbilirubinemias

Answer 9

Impaired transport

• Dubin-Johnson Syndrome
• Rotor Syndrome

Biliary epithelial damage

• Hepatitis
• Cirrhosis
• Liver failure

Intrahepatic biliary obstruction

• PBC
• PSC
• Drugs - chlorpromazine, arsenic

Extrahepatic biliary obstruction

• pancreatic neoplasm
• pancreatitis
• cholangiocarcinoma
• Choledocholithiasis
• Biliary strictures

Question 10

Cholelithiasis

Answer 10

Risk: fat, fertile, females, over forty

Types: cholesterol stone, pigmented or mixed

• -> biliary colic - RUQ pain
• obstructs cystic duct or common bile duct
• CCK increased pressure in closed/obstructed system
• -> pain w/ eating
• -> pneumobilia - air in biliary tree
• fistula between gallbladder and SI
• -> gallstone ileus
• intermittent GI tract obstruction - ileum

Dx: RUQ U/S
HIDA scan

Question 11

Cholangitis

Answer 11

Inflammation, infeciton of biliary tree

Sx:
Charcot’s triad: jaundice, fever, RUQ pain
Reynald’s pentad: hypotension, altered mental status

Question 12

Cholecystitis

Answer 12

Infection and inflammation of gallbladder
+ Murphy sign

Causes: gallstones, ischemia, CMV

tx: Abx, cholecystectomy