PATHOLOGY - Patterns of Liver Disease

Question 1

What are the three zones of a hepatic lobule?

Answer 1

• Periportal
• Midzonal
• Centrilobular

Question 2

Which zone of the hepatic lobule is most vulnerable to hypoxic and toxic injury?

Answer 2

Centrilobular region

Question 3

List the six functions of the liver

Answer 3

• Bilirubin metabolism
• Bile acid metabolism
• Lipid metabolism
• Xenobiotic (foreign substance) metabolism
• Protein synthesis
• Immune function

Question 4

List the eight different methods of liver disease/injury

Answer 4

• Vascular
• Inflammatory (infectious, immune-mediated)
• Trauma
• Anomaly
• Metabolic
• Idiopathic
• Neoplastic
• Degenerative

Question 5

What is icterus?

Answer 5

Another term for jaundice

Question 6

Where in the body is it easiest to see jaundice/icterus? Why is this?

Answer 6

The oropharynx and the sclera of the eye as bilirubin has a higher affinity for elastic tissue

Question 7

How much bilirubin is required to classify hyperbilirubinaemia?

Answer 7

0.5mg/dl

Question 8

How much bilirubin is required to see icterus/jaundice?

Answer 8

2mg/dl

Question 9

How long does it take for there to be maximum accumulation of bilirubin in the body?

Answer 9

2 days

Question 10

What are the classifications of hyperbilirubinaemia?

Answer 10

• Pre-hepatic hyperbilirubinaemia
• Hepatic hyperbilirubinaemia
• Post-hepatic hyperbilirubinaemia

Question 11

What is the cause of pre-hepatic hyperbilirubinaemia?

Answer 11

Haemolysis

Question 12

What are the potential causes of hepatic hyperbilirubinaemia?

Answer 12

• Decreased functional hepatic mass
• Intra-hepatic cholestasis
• Anorexia/fasting (especially in horses)

Question 13

What are the potential causes of post-hepatic hyperbilirubinaemia?

Answer 13

• Obstructive extra-hepatic cholestasis
• Biliary adenoma or cholangiocellular carcinoma (biliary tumours)
• Cholelithiasis (gall stones)

Question 14

What is cholestasis?

Answer 14

The impairment or stop of bile flow

Question 15

What are the possible causes of cholestasis?

Answer 15

• Impaired bile secretion from hepatocytes
• Obstruction of the intra- or extra-hepatic bile ducts

Question 16

What is hepatic regeneration?

Answer 16

Replication of mature hepatocytes and an increase in the size of pre-existing hepatic lobules

Question 17

What is required during hepatic regeneration to prevent fibrosis and the formation of hepatic nodules?

Answer 17

The basement membranes supporting hepatocyte arrangement within hepatic lobules

Question 18

What does centrilobular fibrosis indicate about the aetiology of the injury?

Answer 18

Centrilobular fibrosis indicates chronic toxicity or anaemia

Question 19

What does periportal fibrosis indicate about the aetiology of the injury?

Answer 19

Periportal fibrosis indicates chronic inflammation

Question 20

Describe the appearance of cirrhosis

Answer 20

• Nodulated due to attempted hepatic regeneration
• Scarring and firm due to fibrosis

Question 21

List five possible causes of cirrhosis

Answer 21

• Chronic toxicity
• Chronic cholingitis
• Chronic cholestasis
• Chronic hepatitis
• Idiopathic

Question 22

What is cholangitis?

Answer 22

Inflammation of the bile duct system

Question 23

What is hepatitis?

Answer 23

Inflammation of the liver

Question 24

What is the main consequence of cirrhosis?

Answer 24

Liver failure

Question 25

List five of the other consequences of cirrhosis

Answer 25

- Hepatic encephalopathy - Hyperbilirubinaemia - Coagulation disorders - Panhypoproteinaemia - Portosystemic shunting

Question 26

List the three main ways disease inducing agents enter the liver

Answer 26

- Direct entry - Haematogenous (carried by the blood) - Retrograde biliary transport

Question 27

List the six hepatic defences against disease

Answer 27

- Skin - Ribcage - Omentum - Kupffer cells - IgA antibodies in the billary tree - Terminal sphincter of the billary tree

Question 28

Which disease causes are indicated by focal hepatic lesions?

Answer 28

- Neoplasia - Vascular - Trauma

Question 29

Which disease aetiologies are indicated by random, multifocal hepatic lesions?

Answer 29

- Metastatic neoplasia - Infection - Hyperplasia

Question 30

Which disease aetiologies are indicated by diffuse hepatic lesions?

Answer 30

- Toxins - Hypoxia - Metabolic disease - Degenerative disease

Question 31

Give examples of neoplastic focal liver disease

Answer 31

- Hepatocellular adenoma - Hepatocellular carcinoma - Billary adenoma - Cholangiocellular carcinoma - Carcinoid

Question 32

Why is infarction of the liver very rare?

Answer 32

Due to the dual blood supply from the hepatic portal vein and the hepatic artery

Question 33

What is most likely to cause vascular damage to the liver?

Answer 33

Torsion of the liver lobes

Question 34

In which species is hepatic nodular hyperplasia most common?

Answer 34

Dogs

Question 35

Which metastatic neoplasia is most commonly found on the liver?

Answer 35

Metastatic lymphoma

Question 36

List three examples of viruses which directly attack the liver

Answer 36

- Herpesviruses - Infectious canine hepatitis - Rabbit haemorrhagic disease virus

Question 37

Which disease directly attacks the liver causing haemorrhage and hepatocyte displacement?

Answer 37

Leptospirosis

Question 38

List the two main haematogenous causes of liver abscesses in cattle

Answer 38

- Secondary to rumenitis - Secondary to omphalitis

Question 39

Give a specific example of a trematode parasite which causes disease within the liver

Answer 39

Fasciola hepatica (liver fluke)

Question 40

How long does it take the liver to look histologically normal after a single non-lethal insult?

Answer 40

1 week

Question 41

What is the result of single/multiple lethal hepatotoxic insults?

Answer 41

Hepatic necrosis

Question 42

What is the result of chronic hepatotoxic insult?

Answer 42

Fibrosis and eventual cirrhosis

Question 43

What are the possible causes of hypoxic damage to the liver?

Answer 43

- Anaemia - Congestive heart failure

Question 44

On gross examination, what would be the early sign of hepatic hypoxia?

Answer 44

Yellow centrilobular areas

Question 45

On gross examination, what would be the signs of severe/chronic hypoxia of the liver?

Answer 45

Red centrilobular areas (haemorrhage and necrosis) and yellow periportal areas

Question 46

On gross examination, what would be the appearance of a liver with hepatic amyloidosis?

Answer 46

- Yellow - Waxy

Question 47

Why should you not take a biopsy of a liver that is suspected to have hepatic amyloidosis?

Answer 47

Because livers suffering from hepatic amyloidosis are prone to rupture and haemorrhage