gallstones
DESCRIPTION
BIOCHEMISTRYTRANSCRIPT
LEARNING OUTCOMES
Definition of gallstonesTypes of gallstonesFactors causing gallstonesFeatures of gallstonesInvestigations of gallstonesTreatment of gallstones
DEFINITION
Gallstone formation is most common disorder of biliary tree
Presence of stone in biliary tract is called gallstone or cholelithiasis
Commonly associated with 5 F’s : female, forty, fertile, fair and fat
Either cholesterol gallstones or pigment stones
PATHOPHYSIOLOGY
Cholesterol gallstones- Cholesterol is held in solution in bile - By its association with bile acids and
phospholipids in form of micelles and vesicles- Biliary lipoproteins have a role in solubilizing
cholesterol- In gallstone disease, liver produces bile- Contains an excess of cholesterol- Either a relative deficiency of bile salts or
relative excess of cholesterol
- Bile which is supersaturated with cholesterol is termed “lithogenic”
Factors leading to production of lithogenic bile
1) Defective bile salt synthesis
2) Excessive intestinal loss of bile salts
3) Over-sensitive bile salt feedback
4) Excessive cholesterol secretion
5) Abnormal gallbladder function
- Nucleation factors are factors initiating crystallization of cholesterol in lithogenic bile
- Patients with cholesterol gallstones have gallbladder bile which forms cholesterol crystals
- rapidly than equally saturated bile from patients who do not form gallstones
- Nucleation factors include mucus, calcium, fatty acids
- Anti-nucleation factors are apolipoproteins
RISK FACTORS FOR CHOLESTROL GALLSTONES
Increase cholesterol secretion
Impaired gallbladder emptying
Decrease bile salt secretion
1) Old age 1) Pregnancy 1) Pregnancy
2) Female 2) Gallbladder stasis
3) Pregnancy 3) Fasting
4) Obesity 4) Total parenteral nutrition
5) Rapid weight loss
5) Spinal cord injury
Pigment stones- Brown crumbly pigment stones usually
caused due to consequence of bacterial or parasitic infection in biliary tree
- Infection of biliary tree allows bacterial beta-glucuronidase to hydrolyse conjugated bilirubin to its free form
- Then precipitates as calcium bilirubinate
COMPOSITION OF PIGMENT STONES
Black BrownComposition 1)Polymerised
calcium2)Bilirubinates3)Mucin
glycoprotein4)Calcium
phosphate5)Calcium
carbonate6)Cholesterol
1)Calcium bilirubinate
2)Crystals3)Mucin
glycoprotein4)Cholesterol5)Calcium
palmitate/stearate
RISK FACTORS OF PIGMENT STONES
Black BrownRisk factors 1)Haemolysis
2)Age3)Hepatic
cirrhosis4)Ileal
resection
1)Infected bile2)stasis
CLINICAL FEATURES
Majority of gallstones are asymptomaticSymptomatic stones within the gallbladder
manifest as either biliary pain or cholecystitisIf gallstone becomes acutely impacted in cystic
duct, patient will experience painTypically the pain occurs suddenly and persists
up to 2 hoursUp to 6 hours, cholecystitis or pancreatitis may
be presentPain usually felt in epigastrium (70%) or right
upper quadrant (30%)
Medical dissolution of gallstone can be attempted
Long-term oral administration of bile acid ursodeoxycholic acid
Should consider in those with :1) Radiolucent gallstones2) Stones smaller than 15mm diameter3) Moderate obesity4) No or at most mild symptoms
MANAGEMENT
Gallbladder stones Bile duct stones1)Cholecystectomy :
Open or laparoscopic
2)Oral bile acids : chenodeoxycholic
1)Lithotripsy (endoscopic)
2)Endoscopic sphincterotomy and balloon trawl
3)Surgical bile duct
COMPLICATIONS OF GALLSTONES
1) Empyema of gallbladder2) Choledolithiasis3) Acute pancreatitis4) Cancer of gallbladder5) Mirizzi’s syndrome
REFERENCE
G.K Pal, Textbook of Medical Physiology 2th Edition
Davidson’s Principles And Practice Of Medicine 21st Edition