Biliary tract

Question 1

What are the most important diseases of the biliary tract?

Answer 1

• Gallstones
• Inflammation (acute and chronic cholecystitis and cholangitis)
• Malignant tumors

Question 2

List the most important facts about gallstones.

Answer 2

• It is the most common biliary tract disease: high prevalence: 10% to 20% of adult males and 30% to 40% of adult females are affected.
• Two types can be recognized macroscopically and by biochemical analysis:
  
  • Cholesterol stones (80%)
  • Pigmentary bilirubin stones (20%)
• It shows geographic variation and is more common in Native Americans than other ethnic groups.

Question 3

What are the risk factors for cholesterol gallstones?

Answer 3

Risk factors include the six Fs:

1. Female
2. Forty and above
3. Fertile (multiparous)
4. Fat
5. Flatulent (intestinal disease or malabsorption)
6. Familial, including high prevalence in some ethnic groups (e.g., Native Americans)

Question 4

What are the features of cholesterol stones?

Answer 4

Cholesterol stones by definition contain more than 50% cholesterol. These are the typical stones found in obese people. Their incidence increases with age. They occur in two forms:

• Pure cholesterol stones are rare. They are usually large, solitary, and spherical, resembling a bird’s egg. They are hard, and if cracked into pieces, they show a yellow crystalline internal structure.
• Mixed cholesterol stones, accounting for the majority of stones found clinically, are composed predominantly of cholesterol but also contain variable amounts of bilirubin and calcium salts. Most often, these stones are multiple, and 85% of them are radiolucent and cannot be seen on regular x-ray films.

Question 5

Describe the features of pigmentary stones.

Answer 5

Pigmentary stones are either black or brown:

• Black stones are composed of calcium bilirubinate, phosphate, carbonate, and very little cholesterol. They are usually multiple, small, and friable. These stones form in the course of chronic hemolytic anemias, such as sickle cell anemia or thalassemia.
• Brown stones are composed of calcium bilirubinate, fatty acids, and cholesterol but do not contain calcium phosphate or carbonate. These stones form in the course of bacterial infections causing deconjugation of bilirubin and in prolonged biliary stasis.

Question 6

What are the features of acute cholecystitis?

Answer 6

Acute cholecystitis is a common disease. Typically, it has the following characteristics:

• Females are affected more often than males.
• It is associated with gallstones in 90% cases, but they may be acalculous (10%).
• Secondary bacterial infection follows the obstruction in some cases; Escherichia coli is the most common pathogen.
• Typical symptoms include acute onset of pain in the right upper quadrant, fever, and leukocytosis, usually after a heavy meal.
• Mild jaundice is present in 20% of cases because of the impaction of small stones in the common bile duct.
• Pathologically, the gallbladder is dilatated because of cystic duct obstruction; its wall is swollen, and there may be fibrinous exudates on the serosa (if the inflammation is transmural).
• There are microscopic signs of purulent inflammation (neutrophils) in the mucosa or deeper layers of the wall.
• Recovery is 90% if the obstruction of bile flow is relieved.

Question 7

What is chronic cholecystitis?

Answer 7

This common inflammatory disease affects females more than males. It is the result of repeated attacks of acute cholecystitis or chronic irritation with gallstones. Clinically it presents with indistinct pain in the right upper quadrant 1 or 2 hours after meals.

It is associated with gallstones in 90% of cases. Bacteria (usually E. coli) are found in 30% of cases but are considered to be a form of secondary infection of previously damaged gallbladder.

Pathologic features include the following:

• Gallstones in the lumen
• Biliary gravel (thick viscous bile with microconcretions)
• Edematous mucosa, focally ulcerated or indurated
• Wall of gallbladder may be thickened and fibrotic (firm)
• Microscopic examination reveals chronic inflammatory infiltrates and extension of mucosal sinuses into the muscularis (so-called Rokitansky-Aschoff sinuses)

Question 8

Describe the ‘‘porcelain gallbladder.’’

Answer 8

This term is used for gallbladders that have a thick, calcium-encrusted wall. Typically such gallbladders are expanded and have a rigid, thick, white wall. This pathologic change is a consequence of transmural chronic inflammation, evoking extensive fibrosis during the repair phase of the disease. Scarring of the wall, combined with dystrophic calcification, transforms the gallbladder into a porcelain-like vessel. The calcium-encrusted gallbladder can be seen on standard x-ray films.

Question 9

List the features of gallbladder carcinoma

Answer 9

• Uncommon form of cancer (It accounts for only 5% of all gastrointestinal cancers.)
• More common in females than in males & Affects older persons (average age, 65 years)
• Associated with gallstones in 90% of cases
• Porcelain gallbladder (encrusted fibrotic chronic cholecystitis) is a high-risk condition
• Ethnic distribution (the same as for gallbladder stones): More common in some Native Americans, such as the Pima Indians
• Adenocarcinoma (90%) and squamous cell carcinoma (10%) (Squamous cell carcinoma arises from squamous metaplasia in chronic cholecystitis and cholelithiasis.)
• Poor prognosis (5% 5-year survival rate

Question 10

List the features of carcinoma of the common bile duct.

Answer 10

• Uncommon form of cancer
• Male-to-female ratio is 1:1
• No comorbidity with gallstones
• Jaundice is an early sign of disease (even small tumors cause obstruction)
• Adenocarcinomas in 100% of cases
• Poor prognosis (35% 5-year survival rate)