Fiser Chapter 32 BILIARY SYSTEM Flashcards
Gallbladder function
Stores bile
Concentrates bile by active resorption of NaCl and water (has more sodium, bile salts, and cholesterol than hepatic bile; hepatic bile has more chloride)
Postprandial emptying (maximum at 2 hours)
Cholecystectomy -> decreased total bile salt pools
45yo man with UC presents with jaundice, fatigue, pruritis, weight loss, and RUQ pain
Primary sclerosing cholangitis: associated with UC, pancreatitis, DM
Multiple strictures throughout hepatic ducts (string of beads)
Leads to portal HTN, hepatic failure (progressive fibrosis of intrahepatic and extrahepatic ducts) -> cirrhosis, cholangiocarcinoma
Tx: PTC tube drainage, choledochojejunostomy or balloon dilatation of dominant strictures may provide symptomatic relief, cholestyramine to decrease bile acids and pruritis, UDCA (ursodiol) to decrease bile acids and improve liver enzyms; LIVER TXP EVENTUALLY NEEDED FOR MOST; Colon resection does NOT help PSC
Cholangitis dx
Elevated AST/ALT, bilirubin, alk phos, WBC
US shows dilated CBD (> 8 mm, > 10 mm after cholecystectomy) if d/t biliary obstruction
GB wall normal size
< 4 mm
Pigmentes stones
Most common worldwide
- Calcium bilirubinate stones: from increased bilirubin load, decreased hepatic function, and bile stasis -> solubilization of unconjugated bilirubin with precipitation; dissolution agents (monooctanoin) do NOT work
- Black stones: Hemolytic disorders, cirrhosis, ileal resection (loss of bile salts), chronic TPN; tx cholecystectomy if symptomatic
Cholecystitis most common organisms
E coli (#1), Klebsiella, Enterocococcus
Biliary colic
Transient cystic duct obstruction caused by passage of gallstone
RESOLVES IN 4-6 HOURS
Patient with sepsis following lap chole
- Fluid resuscitation, stabilize
- US to look for dilated intrahepatic ducts or fluid collection (cystic duct leak versus transection)
- Could also be cholangitis
Charcot’s triad
RUQ pain, fever, jaundice
Reynaud’s pentad: altered mental status and shock
Diabetic with severe rapid-onset abdominal pain, nausea, vomiting, sepsis, gas in gallbladder wall on plain film
Emphysematous gallbladder disease: risk of perforation
Usually d/t clostridium perfringens
Tx: emergent cholecystectomy, percutaneous drainage if unstable
Enterohepatic circulation
- Bile secreted by hepatocytes (80%) and bile canalicular cells (20%); broken down in gut to stercobilin (makes stool brown); reabsorbed
- Terminal ileum: active resorption of conjugated bile salts; Small intestine (45%) and colon (5%): passive resorption of non-conjugated bile salts
- Absorbed bile gets converted to urobilinogen and eventually urobilin, which is released in urine (yellow color)
Drugs that affect sphincter of Oddi
Morphine: contracts (why meperidine used to be used)
Glucagon: relaxes
Cholesterol and bile acid synthesis
HMG CoA -> (HMG CoA reductase) -> cholesterol -> (7-alpha-hydroxylase) -> bile salts (acids)
HMG CoA reductase is rate limiting step in cholesterol synthesis
Shock after lap chole causes
First 24 hours: hemorrhagic shock from clip that fell off cystic artery
After 24 hours: septic shock from accidental clip on CBD with subsequent cholangitis
Gallstone risk factors
> 40yo
Female
Obesity
Pregnancy
Rapid weight loss
Vagotomy
TPN (pigmented stones)
Ileal resection (pigmented stones)
Most sensitive test for cholecystitis
CCK-CS test (cholecystokinin cholescintigraphy), also uses HIDA scan (technetium taken up by liver and excreted in biliary tract)
Indications for cholecystectomy afterward:
- GB not seen (stone in cystic duct)
- Take >60 min to empty (chronic cholecystitis)
- EF < 40% (biliary dyskinesia)
Cystic vein
Drain into R branch of portal vein
Best treatment for late CBD stone
ERCP (sphincterotomy allows for removal of stone)
Risks: bleeding, pancreatitis, perforation
Most common cause of positive bile cultures
Postoperative strictures, usually E coli, or polymicrobial
Longitudinal blood supply of hepatic and common bile ducts
Right hepatic artery (9 oclock on ERCP), gastroduodenal artery retroduodenal branches (3 oclock on ERCP)
Pancreatic duct normal size
< 4 mm
Rokitansky-Aschoff sinuses
Epithelial invaginations in GB wall, formed from increased gallbladder pressure
Patient with sepsis, cholangitis, and jaundice
Bile duct stricture: cancer until proven otherwise (unless history of pancreatitis or biliary surgery)
Dx: MRCP to define anatomy, look for mass -> ERCP with brush biopies
Tx: if d/t ischemia or chronic pancreatitis -> choledochojejunostomy (best long-term solution), otherwise if cancer then appropriate workup
Todani classification of choledochal cysts
I: saccular or fusiform dilatation of a portion or whole CBD
II: isolated diverticulum from CBD
III: right by duodenum
IV: multiple (extrehepatic +/- intrahepatic)
V: intrahepatic (if multiple intrahepatic, is Carroli’s disease)
Cystic artery anatomy
Branches off right hepatic artery
Found in triangle of Calot (cystic duct latera, CBD medial, liver superior)
Most common route of bacterial infection of bile
Dissemination from portal system (NOT retrograde through sphincter of ODD)
Benign neuroectoderm tumor of gallbladder
Granular cell myoblastoma: can occur in biliary tract with signs of cholecystitis
Tx: cholecystectomy