Page 460 - Concise Pathology for Exam Preparation ( PDFDrive )

15 Diseases of the Hepatobiliary System and Pancreas 445

Q. Write briefly on the clinicopathological features of pyogenic liver
abscess.
Ans. Clinicopathological features of pyogenic liver abscess
• Bacteria reach the liver by:
• Vascular seeding (via portal blood in appendicitis, diverticulitis and perforated bowel
and via hepatic artery in systemic bacteraemia).
• Ascending cholangitis
• Direct extension from a contiguous focus of infection, like subphrenic abscess
• Penetrating injury
• Solitary abscess is usually located in the right lobe of liver and results from direct exten-
sion of infection and trauma.
• Multiple abscesses are seen in elderly patients, and are usually due to ascending chol-
angitis.
• E. coli, Klebsiella species, anaerobic streptococci and Bacteroides are the common caus-
ative organisms.
• Clinical features include fever, right upper quadrant pain and tender hepatomegaly.
• Small lesions respond to antibiotics whereas larger lesions need surgical drainage.

BILIARY TRACT

Q. Write briefly on the aetiopathogenesis, clinicopathological features
and complications of gallstones.

Ans. Gallstones affect 10–20% of adult males and 30–40% of adult females.

Types
1. Cholesterol (contain more than 50% of crystalline cholesterol monohydrate); more
common in the west
2. Pigment (main constituents are bilirubin and calcium); more common in Asians

Cholesterol Stones
Risk Factors
• Demography: Western more than Asians
• Advancing age
• Female gender, oral contraceptives, pregnancy, obesity and rapid weight reduction
• Reduced gallbladder motility
• Inborn disorders of bile acid metabolism
• Hyperlipidaemia syndromes
Salient Features
• They occur in two forms:
• Pure cholesterol stones: Rare, large, solitary, spherical and finely granular, with a
yellow glistening radiating crystalline internal structure.
• Mixed cholesterol stones: They account for the majority of stones found clinically
and 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.
Pathogenesis (Flowchart 15.4)
• Cholesterol which is normally water insoluble becomes water soluble when it complexes
with bile salts and lecithins secreted into bile.
• When excess cholesterol accumulates in the bile, it supersaturates (does not remain dis-
solved anymore and precipitates out). This results in its nucleation into solid cholesterol
monohydrate crystals.

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