Gall stones Flashcards
What are 3 different types of gallstone?
- cholesterol stones (20%)
- pigment stones (5%)
- mixed stones (75%)
What are the risk factors for cholelithiasis/gallstone disease?
- increasing age
- female sex
- hispanic + native-american ethnicity
- FHx of gallstones
- gene mutations
- pregnancy/exog oestrogen
- obesity, diabetes
- non-alcoholic liver disease
- TPN
What is the composition of bile?
- bilirubin - by-prod of haem degradation
- cholesterol - kept soluble by bile salts + lecithin
- bile salts/acids - mostly reabsorbed in terminal ileum
- lecithin - increases solubility of cholesterol
- inorganic salts - sodium bicarb to keep bile alkaline to neutralise gastric acid in duodenum
- water - makes up 97% of bile
What is the pathogenesis of cholesterol stones forming?
- imbalance between bile salts/lecithin and cholesterol
- allows cholesterol to precipitate out of solution and form stones
What is the pathogenesis of pigment stones forming?
- occur due to excess of circulating bile pigment
- eg. haemolytic anaemia
What other factors influence pathogenesis of gallstones?
- stasis (eg. pregnancy)
- ileal dysfunction (prevents re-absorption of bile salts)
- obesity and hypercholesterolaemia
What are the clinical features of biliary colic?
- intense RUQ/epigastric pain
- radiates to right side
- might radiate to tip of shoulder/back
- nausea and vomiting
- postprandial pain
What are complications of gallstones?
- biliary colic
- acute cholecystitis
- GB empyema, gangrene, perforation
- obstructive jaundice
- ascending cholangitis
- pancreatitis
- gallstone ileus
What are differential diagnoses for RUQ pain?
- gallstone disease (+ related complications)
- gastritis/duodenitis
- peptic ulcer disease/perforated peptic ulcer
- acute pancreatitis
- right lower lobe pneumonia
- MI
How would you differentiate between the gallstone complications?
What link does Crohn’s disease have to gallstones?
- Crohn’s predisposes to development of gallstones
- Due to malabsorption of bile salts from terminal ileum
- Affected individual becomes depleted in bile salts
- They do not have enough bile to maintain the cholesterol dissolved in bile
- Thus cholesterol stones form
What investigations can be done for gallstones?
- Ultrasound of gallbladder -> identify 90% of gallstones
- Liver function tests to assess liver fxn
What ducts meet to form the common bile duct?
- Cystic duct from gallbladder
- Common hepatic duct (from R + R hepatic ducts)
- Come together to form common bile duct (outside the liver)
Remember, most patients with gallstones are asymptomatic. How might patients with symptomatic gallstones present?
- Biliary colic or cholecystitis (>90% of symptomatic presentations)
- Jaundice +/- ascending cholangitis
- Acute pancreatitis
- Gallstone ‘ileus’
How does a biliary colic come about and how does this present?
- if a gallstone impacts in + obstructs the cystic duct
- the gallbladder will contract against the acutely obstructed duct
- resulting in symptoms of biliary colic:
- upper abdo/RUQ pain, may radiate to back/tip of scapula, often nausea + vomiting
If imaging shows gallstones + history compatible then laparoscopic cholecystectomy
How does acute cholecystitis develop from a gallstone?
- if the impacted stone occludes cystic duct for a prolonged period of time
- it will rub + damage the mucosal lining
- thereby inciting an acute inflammatory response in gallbladder wall
- there is development of acute cholecystitis
- presence of fever indicates acute cholecystitis (or cholangitis)
Imaging (USS) + cholecystectomy (ideally <48hrs of presentation)
What is acute acalculous cholecystitis?
- acute cholecystitis without gallstones
- thought to result from ischaemia
- the cystic artery is an end artery w/ no collateral circulation
- it occurs in pts who are hospitalised for conditions unrelated to gallbladder eg. hypotension + multiorgan failure; major trauma/burns; infections
- clinical symptoms tend to be insidious since they are obscured by underlying condition
- a high % of pts have no symptoms referable to gallbladder; diagnosis therefore rests on a high index of suspicion
- as a result of either delay in dx or disease itself, incidence of gangrene + perforation is much higher in acalculous cholecystitis than cholecystitis due to gallstones
Rx → if pt fit then cholecystectomy, if unfit then percutaneous cholecystectomy
What is chronic cholecystitis?
- repeated episodes of biliary colic + acute cholecystitis
- results in chronic inflammation w/ healing by fibrosis
- as a consequence, gallbladder wall becomes thickened + the gallbladder shrinks in size
How do gallstones cause jaundice?
- if a gallstone impacts + obstructs the common bile duct (choledocholithasis), it will cause obstructive jaundice
- the jaundice develops bc bile is unable to drain into the duodenum for excretion
A serious complication of a gallstone obstructing the common bile duct is the development of ascending cholangitis. What is this?
- inflammation of common bile duct
- the biliary obstruction causes stasis
- predisposes to superimposed infection: gut bacteria (usually gram negative eg. E coli, Klebsiella) gain entry to biliary tree via ampulla of Vater
Rx → fluids, broad-spectrum IV Abx, correct coagulopathy, early ERCP
How does ascending chlangitis typically present clinically?
- Charcot’s triad
- jaundice, fever (usually w rigors) + RUQ pain
What happens if ascending cholangitis is left untreated?
- infection may ascend up to the liver
- causing abscesses
- and/or cause sepsis
- serious condition if left untreated has a high mortality
Gallstones are the commonest cause of acute pancreatitis. How do gallstones cause acute pancreatitis?
- if gallstone passes down common bile duct
- obstructs Ampulla of Vater
- results in pancreatitis
- there is reflux of pancreatic secretions back up the pancreatic duct -> pancreatic autodigestion -> pancreatitis
What is gallstone ‘ileus’?
- When a large gallstone causes small bowel obstruction
- Stone erodes through gallbladder into duodenum; then obstructs terminal ileum
- Gallstone enters the small bowel via a fistula, which forms between the inflamed wall of GB and a loop of small bowel
Rx → laparotomy + removal of gallstone from small bowel: enterotomy must be made proximal to site of obstruction + not at site of obstruction. Fistula between gallbaldder + duodenum should not be interfered with
