Biliary Tract Disorders and Gallstones

Biliary Tract Disorders

• Biliary atresia: A condition where the extrahepatic biliary tree fails to form or is destroyed early. This leads to biliary obstruction within the first two months of life, causing jaundice and progressing to cirrhosis.

Cholelithiasis (Gallstones)

• Composition: Gallstones are solid, round stones formed in the gallbladder. They are primarily composed of cholesterol (90% in Western populations) or bilirubin.
• Formation factors: Gallstone formation is linked to supersaturation of bile with cholesterol or bilirubin, reduced phospholipid or bile acid levels, or stasis.
• Cholesterol stones (most common): These stones are typically yellow and radiolucent. Risk factors include age (40s), estrogen exposure (females), obesity, multiple pregnancies, oral contraceptives, certain medications (clofibrate), Native American ethnicity, Crohn's disease, and cirrhosis.
• Bilirubin stones: Composed of bilirubin, these stones are usually radiopaque. Risk factors include extravascular hemolysis (increased bilirubin in bile) and biliary tract infection (bacteria like E. coli, or parasites like Ascaris lumbricoides and Clonorchis sinensis).

Complications of Gallstones

• Biliary colic: Pain from the gallbladder contracting against a stone lodged in the cystic duct.
• Acute cholecystitis: Inflammation of the gallbladder. Impacted stones lead to pressure ischemia, bacterial overgrowth, and inflammation typically causing pain in the right upper quadrant that may radiate to the right shoulder and scapula.
• Chronic cholecystitis: Chronic inflammation often caused by longstanding gallstones and characterized by herniation of the gallbladder mucosa (Rokitansky-Aschoff sinus).
• Gallstone ileus: When a gallstone passes into the small intestine, obstructing it.
• Gallbladder cancer: A rare but possible consequence, especially in cases with porcelain gallbladder (a dystrophic calcification)

Other Relevant Conditions

• Ascending cholangitis: A bacterial infection of the bile ducts, typically ascending from the enteric system. Characterized by sepsis (high fever and chills), jaundice, and abdominal pain, and is commonly associated with choledocholithiasis (stones in the common bile duct).
• Gallstone ileus: Occurs when a gallstone passes into the small bowel and obstructs it, typically due to a fistula (connection) between the gallbladder and the small bowel.
• Gallbladder adenocarcinoma: Cancer of the gallbladder, often associated with long-term gallstones particularly in elderly women. This often presents as cholecystitis. Poor prognosis.