What are Gallbladder Calculi?
Gallbladder calculi, commonly known as gallstones, are solid crystalline deposits that form within the gallbladder, affecting 10-15% of the general population. 1
Definition and Composition
Gallbladder calculi are pathological formations composed primarily of:
- Cholesterol stones: Made of cholesterol monohydrate crystals, forming in sterile gallbladder bile 2
- Pigment stones: Composed of calcium salts of bilirubin, phosphate, carbonate, and other anions 3
Pathophysiology
The formation of gallstones follows a specific sequence 2:
- Biliary supersaturation (hepatic origin): Excessive secretion of cholesterol or bilirubin conjugates, and/or deficient secretion of bile salts and lecithin
- Nucleation: Imbalance in pro- and antinucleating biliary proteins, hypersecretion of gallbladder mucin, and gallbladder dysmotility
- Crystallization: Results in "biliary sludge" - suspension of cholesterol crystals or bilirubinate salts in gallbladder mucin gel 5
- Stone formation: Sludge contains particles 1-3 mm called microliths, which are obligatory intermediate steps in all gallstone development 5
Clinical Significance
Between 20-40% of patients with gallstones will develop gallstone-related complications, with an annual incidence of 1-3%. 1 Acute calculus cholecystitis (ACC) is the first clinical presentation in 10-15% of cases.
Common Complications Include:
- Biliary colic
- Acute cholecystitis
- Choledocholithiasis (common bile duct stones)
- Acute pancreatitis
- Cholangitis 6
Diagnostic Approach
Abdominal ultrasound is the preferred initial imaging technique for suspected gallstone disease due to its cost-effectiveness, wide availability, reduced invasiveness, and good accuracy. 1 Approximately 50% of pigment stones are radioopaque and account for two-thirds of all opaque stones 3.
Important Caveat:
While ultrasound is excellent for detecting gallstones, it has limited utility for definitively ruling in or ruling out acute calculus cholecystitis according to adopted diagnostic criteria 1.