A 44-year-old woman reports frequent episodes of severe pain in the mid and upper right-side of her abdomen that usually occurs shortly after her evening meal and sometimes at night. She is obese, but otherwise healthy. The pain lasts for several hours and is steady and often causes vomiting. On physical examination she complains of slight tenderness in the right upper quadrant (RUQ). An ultrasound confirms the presence of gallstones (Figure 62-1).
Ultrasound showing two echogenic gallstones in the gallbladder. Note the absence of echoes posterior to the gallstone called “shadowing” (arrowheads). (From Schwartz's Principles of Surgery, Ninth Edition, New York, NY: McGraw-Hill; 2010:1141, Fig. 32-6. Copyright 2010, McGraw-Hill.)
Gallstones are concretions (inorganic masses), usually composed of cholesterol, that form in the gallbladder or bile duct. They are formed by concretion (joining together of adjacent parts and hardening) or accretion (growth by addition or adherence of parts normally separated) of normal and/or abnormal bile constituents.
- Based on autopsy data, 20% of women and 8% of men have gallstones.1
- Approximately 20 million people in the United States are affected, with 1 million new cases each year.1
- In a Swedish incidence study of 621 randomly selected individuals ages 35 to 85 years, 42 (8.3%) of the 503 subjects available at 5 years developed gallstones; this yielded an incidence for newly developed gallstones of 1.39 per 100 person-years.2
- Among pregnant women, 5% to 12% have gallstones and 20% to 30% have gallbladder sludge (thick mucous material containing cholesterol crystals and mucin thread or mucous gels). Gallbladder sludge is a possible precursor form of gallstone disease.1
- Patients with asymptomatic gallstones have a 1% to 2% risk per year of developing symptoms or complications of gallstones. Based on data primarily for men, this will occur in 10% by 5 years, 15% by 10 years, and 18% by 15 years following diagnosis.1
- Gallstone disease is responsible for approximately 10,000 deaths per year in the United States. Most (7000) of these deaths are attributable to acute gallstone complications (e.g., cholecystitis, pancreatitis, cholangitis).3
- Although gallbladder cancers most often occur in the setting of stones (91% of 34 patients with gallbladder cancer in one study),4 gallbladder cancer is rare. An incidence rate of 0.28% for incidental gallbladder carcinoma was reported in a Swiss database study of a population of more than 30,000 patients undergoing laparoscopic cholecystectomy.5
- There are two types of gallstones: cholesterol stones (80%) and pigmented stones (primarily calcium bilirubinate, 20%).
- The solute components of bile include bile acids (80%), lecithin and other phospholipids (16%), and unesterified cholesterol (4%).1 Cholesterol gallstones form when there is excess cholesterol or an abnormal ratio of cholesterol, bile acids, and lecithin.
- Excess biliary cholesterol can occur from a secondary increase in secretion of cholesterol caused by obesity, high cholesterol diet, clofibrate ...