disorders of the gallbladder and biliary tract Flashcards
Which way does blood flow in the liver? Bile?
Blood flows from portal veins–>central vein
Bile flows from the central vein–>bile ducts
Which zone is first affected by toxic injury? ischemia?
Zone I: portal area = toxic injury
Zone 3: central vein = ischemia
What are sinusoids?
fenestrated capillaries allowing macromolecules in blood to contact hepatocytes through the space of Disse
What prevents bile from exiting the bile canaliculus in between the hepatocytes and accessing the sinusoids?
tight gap junctions
Bile secretion i an active process. What does it depend on?
- microvilli
- cytoskeleton
- interaction of bile with secretory apparatus
- Permeability of bile canaliculus
What is the only mechanism for cholesterol excretion?
bile
What is in bile?
bile salts phospholipids cholesterol bilirubin ions
What is a conjugated bile acid?
Adding an AA (glycine or taurine) to a bile acid which makes is amphiphilic
Where does bilirubin come from? How is it conjugated?
80% of bilirubin comes from erythrocytes. Glucoronyl transferase adds a glucoronic acid to conjugate it.
What do the ducts and ductules do?
Modify the bile by adding HCO3 and water
What is the purpose of the gallbladder?
Concentrates the bile
What elements are concentrated in the gallbladder?
Na
Bile acid
pH
Why do you need an acidic pH for the gallbladder?
Otherwise, CaCO3 will precipitate
What do the bile salts form? Why is this essential?
Micelles. These are essential for digestion, transport, and absorption of fat soluble vitamins (ADEK)
What is contained in micelles? Vesicles?
Micelles: bile acid+cholesterol+phospholipids
Vesicles: cholesterol+phospholipids
What factors can cause gallstone formation?
- Increased cholesterol, with decreased bile acids and phospholipids in the gallbladder
- Decreased contractility of the gallbladder
- High pH
What are the actions of cholescystokinin on the gallbladder?
- Gb contraction
- Sphincter relaxation
- Release of pancreatic enzymes
- Inhibition of gastric emptying
What is the total bile flow/day?
600 ml/day.
450mL=bile salts
150mL=water/salts from the ducts
What are the main functions of bile?
Fat digestion
Absorption of fat soluble vitamins
Cholesterol waste elimination
Which portion of the digestive system has lots of micelles?
jejunum/ileum
Where are most of the bile acids resorbed back into the blood?
Within the ileum (95%)
What are the names of the secondary bile acids? What produces them?
deoxycholate
lithocholate
How much of bile acids arrive in the colon?
1%
What would cause a rise in unconjugated bili (indirect), generally?
- Overproduction of bili
- Defective uptake
- Defective conjugation
What would cause a rise in conjugated (direct) bili?
defective excretion of bilirubin (extrahepatic)
Gilbert’s syndrome
Low levels of glucuronyl transferase (High indirect bili)
Crigler-Najar (type I/type II)
Type I: no GT
Type II: Very low GT
–>In both cases, high indirect bili
Which hereditary condition results in high direct bili?
Dubin Johnson and Rotor syndrome
What is cholestasis?
Blockage in bile flow
What are the clinical criteria for cholestasis?
Jaundice, gray stool, dark urine, pruritis
What labs would you see in cholestasis?
High bili High ALP High GGT High cholesterol Low levels of fat soluble vitamins
What are causes of extrahepatic obsturction?
Gallstones
strictures
neoplasias
parasites
What is a fancy name for gallstones?
cholelithiasis
What are the two types of gallstones? which can you see on an xray?
cholesterol (majority) calcium carbonate (radiopaque)
What are causes of calcium stones?
hemolysis
cirrhosis
biliary infection
What are the physical manifestations of gallstone disease?
70-80% are asymptomatic
If symptomatic, risk of complications
What are complications of gallsotnes?
cholecystitis
-empyema/perforation
choledocholithiasis(stone stuck in duct) -obstructive jaundice -ascending cholangitis -gangrenous GB Pancreatitis (acute mostly)
What are the less common complications of gallstones?
- biliary enteric fistula (can cause a gallstone ileus)
- Gallstone ileus (impaction of a gallstone within the lumen of the small intestine.)
- Porcelain gallbladder (calcification of the gallbladder)
What is a common presentation of cholecystitis?
Epigastric/RUQ pain
Crescendo-plateau-decrescendo pain over a few hours without resolution
N/V
What sign is positive in cholecystitis?
Murphy’s sign
Which labs will be elevated in acute cholecystitis with obstruction?
bilirubin, AST, ALT
What might you see on histology of chronic cholecystitis?
Rokitansky-Aschoff sinus (i.e. infiltration of muscle layer into the mucosa. important to distinguish this from cancer
What is a complication of porcelain gallbladder?
carcinoma of the gallbladder in 20% of patients
n which patients would you see a strawberry gallbladder?
In chronic cholecystitis or cholesterol rich stones. Pathologists will see cholesterol esters in the lamina propria and foamy lipid laden macrophages
Choledocholithiasis
Stones in the duct
What are the lab findings of choledocholithiasis?
Bili
ALP
GGT (AST, ALT)
What imaging do you want if you suspect choledocholithiasis?
Ultrasound will show a dilated CBD
Would you see murphy’s sign in a pt with choledocholithiasis?
NO. the gallbladder is not inflammed.
What are the complications of choledocholithiasis?
cholangitis
pancreatitis
cirrhosis
Is ascending cholangitis a life threatening episode?
YES
What are the Sx of cholangitis?
Charcot’s triad
Reynold’s pentad
What are the components of charcot’s triad?
RUQ pain, jaundice, fever
What are the components of reynold’s pentad?
Charcot + MS changes + shock
What are the risk factors for forming gallstones?
Female Obesity Forty Family history Fertile (or pregnant) -->also, a fatty diet RAPID WEIGHT LOSS Diabetes
If you see cholecystitis in a pregnant woman, what should you do?
perform a cholecystectomy. Safest in 2nd trimester
What is different about cholecystitis in a pregnant woman?
Absent murphy’s sign and AP is less helpful
What is the most sensitive imaging test for gallstones?
US, endoscopic
95% sensitivity
What are the ultrasound findings in choecystitis?
- pericholecystic fluid
2. thickened wall
What is the gold standard diagnostic procedure for choledocholithiasis?
ERCP. Only for therapy–>pull out stone. This is because we have lots of safer diagnostic techniques out there.
Also, There is a 5% risk of pancreatitis
What is a non-invasive way to detect CB
MRCP
It’s also very sensitive and specific
If someone has asymptomatic gallstones, what should you do?
Watch and wait
What is the risk of ERCp?
5% chance of causing pancreatitis
What is an oral therapy for gallstones?
ursodeoxycholic acid. But only for small cholesterol stones with high recurrence rates
What is a definitive treatment for symptomatic gallstones?
cholecystectomy
What is the cause of acute acalculous cholecystitits?
In patients with severe systemic illnesses (ICU) likely cause of ischemia
If you see gallbladder polyps, should you resect?
Yes, if over 1 cm b/c the bigger it is, the greater the risk of becoming cancerous
What is the prognosis for gallbladder carcinoma?
Poor
What are the risk factors for GB carcinoma?
gallstones, chronic cholecystitis, choledochal cysts
Primary sclerosing cholangitis
chronic, fibrosing, inflammatory process of the bile ducts, destroying the biliary tree and causing cirrhosis
What is secondary sclerosing cholangitis?
Chronic biliary obstruction causing secondary fibrosis
What are the different types of choledochal cysts?
Type I: segmental dilations of CBD
Type II: diverticular cysts
Type III: intra and extra hepatic cysts
Type IV: intrahelpatic cysts
Cholangiocarcinoma
Tumor of cholangiocytes in the ducts. Poor survival
Klatskin tumor
Cholangiocarcinoma of the bifurcation
