Biliary Tree and Gallstones

Question 1

Describe the biliary tree.

Answer 1

Biliary canaliculi to
interlobular bile ducts to
septal bile ducts to
intrahepatic ducts to
right and left hepatic ducts to 
common hepatic duct to
common bile duct

Question 2

Where does the bile duct pass?

Answer 2

Passes behind the duodenum, through the head of the pancreas to join the main pancreatic duct, becoming the bile duct.
This then enters the duodenum at the major/minor duodenal papilla

Question 3

Where is the gallbladder located?

Answer 3

In the gallbladder fossa on the inferior surface of the right lobe of the liver

Question 4

What is the epithelial lining and function of the gallbladder?

Answer 4

Columnar epithelium

- concentrates bile by absorbing water and electrolytes

Question 5

What is bile composed of?

Answer 5

Water
Bile acids
Bile pigments 
Phospholipids
Cholesterol
Electrolytes

Question 6

Describe the bile acid synthesis.

Answer 6

Derived from cholesterol in the hepatocyte. Cholic acid is the primary bile acid

Question 7

Describe bile salt synthesis.

Answer 7

Cholic acid is conjugated to bile salts by the addition of an amino acid group (taurine or glycine) before active export. These are primary bile salts.

Question 8

What forms secondary bile salts.

Answer 8

The action of intestinal bacteria (de-hydroxylation) of primary bile salts

Question 9

What causes gallbladder contraction?

Answer 9

Vagal stimulation
CCK release into the duodenum
- causes by detection of luminal fat
- sphincter of Oddi relaxation

Question 10

What causes gallbladder relaxation?

Answer 10

Sympathetic nerves
Gut hormones
- somatostatin
- VIP

Question 11

What do the following and and prefixes mean?
Chol
Lith
Docho
Ang 
itis
iasis

Answer 11

Chol = bile
Lith = stone
Docho = duct
Ang = vessel
itis = inflammation
iasis = process

Question 12

What is the function of bile salts?

Answer 12

Promote emulsification and formation of micelles to help fat absorption
- fat soluble vitamins are absorbed
- facilitates cholesterol excretion by solubilising it in bile
Influences the intestinal metabolic pathways

Question 13

What is the entero-hepatic circulation?

Answer 13

95% of bile salts are reabsorbed from the gut (6-8 times a day)
- they are reabsorbed by the terminal ilium by active transport into the portal vein

Question 14

How do bile salts travel in the blood?

Answer 14

Bound to albumin because it’s hydrophobic

Question 15

What are the risk factors for gallstones?

Answer 15

The six F's
- female
- forty
- fat
- fertile
- family history
Caucasian
Low fibre diet
Inflammatory bowel disease

Question 16

Name the three types of gallstones.

Answer 16

Cholesterol stones
Bile pigment stones
Mixed

Question 17

Describe cholesterol stones.

Answer 17

Usually solitary

Oval and large (up to 3cm)

Question 18

Describe bile pigment stones.

Answer 18

Usually multiple
Hard and irregular
Can be associated with chronic heamolysis (sick cell)

Question 19

Describe mixed stones.

Answer 19

The most common (80%)
Multiple and multi-faceted
Has a laminated structure with layers of bile pigment, cholesterol and calcium salts

Question 20

In gallstone pathogenesis there are three main events (that often occur toegther). What are they?

Answer 20

Cholesterol supersaturation
Biliary stasis
Increased bilirubin secretion

Question 21

Describe the process of cholesterol supersaturation.

Answer 21

Cholesterol is normally solubilised in bile, but very high levels cause supersaturation.
This can be due to increased oestrogen or decreased bile salt levels.

Question 22

When does biliary stasis occur?

Answer 22

Occurs during periods of fasting, starvation or prolonged enteral feeding

Question 23

Describe what happens in increased bilirubin secretion.

Answer 23

Pigmented stones can develop in increased heamolysis or a failure in hepatic conjugation

Question 24

What complications can gallstones in the gallbladder cause?

Answer 24

Acute cholecystitis 
- can cause  jaundice and abnormal LFTs
Empyema
Mucocele
Cancer
Biliary colic
- stone impacted in gallbladder
- pain when eating

Question 25

What complications can gallstones in the common bile duct cause?

Answer 25

Obstructive jaundice
Cholangitits
Pancreatitis

Question 26

What complications can gallstones in the small intestine cause?

Answer 26

Gallstone ileus

Question 27

What are some of the casues of obstructive jaundice?

Answer 27

Choldocholithiasis
Pancreatic cancer
Pancreatitis
Cholangiocarcinoma
Benign bile duct stricture

Question 28

What are the signs and symptoms of obstructive jaundice?

Answer 28

Pale stools and dark urine
Yellow sclera
Hepatomegaly
Itch
S/S of chronic liver disease
Palpable gallbladder

Question 29

Where do gallstones commonly impact in the bile duct?

Answer 29

The ampulla of Vater

Question 30

How do you diagnose a gallstone in the bile duct (choledocholithiasis)?

Answer 30

Ultrasound with or without EUS and MRCP to confirm

Question 31

Treatment of gallstones in the bile duct?

Answer 31

• antibiotics if cholangitis
• ECRP to attempt stone removal (incision in the sphincter of Oddi to increase the diameter)
• cholecystectomy to prevent recurrence

Question 32

What happens to the LFTs in obstructive jaundice?

Answer 32

• ALP increases early (with a GGP increase)
• bilirubin rises steadily (level suggests the duration of disease)
• coagulopathy is common in prolonged obstructive jaundice