Hepatology - liver pathology

Question 1

What appearance does a pig liver have?

Answer 1

Moroccan leather appearance - prominant interlobular connective tissue

Question 2

What animals have non lobulated livers?

Answer 2

Cows and sheep

Question 3

What is a hepatic lobule made up of?

Answer 3

Hepatic acinus - triangular region bounded by the ventral vein

Question 4

What are the 3 main circulatory disorders affecting the liver?

Answer 4

Congenital portosystemic shunts
Post hepatic OUTFLOW conditions
Intra-hepatic/pre-hepatic conditions associated with abnormal portal vein INFLOW

Question 5

What is a congenital portosystemic shunt?

Answer 5

Anomalous venous connection between the portal system and the venous systemic system - allows the portal blood to bypass the hepatic parenchymal sinusoids straight to the vena cava

Question 6

What are the two different types of congenital portosystemic shunt?

Answer 6

Extra hepatic
Intra hepatic

Question 7

What size dog gets an extra hepatic shunt? What size gets an intra-hepatic shunt?

Answer 7

Extra-hepatic - small (wEe) dogs breeds
Intra-hepatic - large (bIg) dogs breeds

Question 8

Where does an intrahepatic congenital portosystemic shunt originate from and end at?

Answer 8

Originates at right or left portal vein branch
Into hepatic vein or directly into caudal vena cava

Question 9

Where does an extrahepatic congenital portosystemic shunt originate from and end at?

Answer 9

Originates from left or right gastric vein or splenic vein
Into caudal vena cava or azygous vein

Question 10

What are the functional consequences of congenital portosystemic shunts?

Answer 10

Reduced hepatic perfusion
Small liver - microhepatica
Poor growth
Hepatic encephalopathy - due to toxins

Question 11

Will congenital portosystemic shunts result in increased blood pressure in the portal venous system (portal hypertension)?

Answer 11

No - lower resistance pathway so wont increase pressure in the portal venous system

Question 12

What post hepatic conditions affect outflow of blood from the liver?

Answer 12

Heart disease - right sided congestive heart failure
Obstruction of hepatic vein/caudal vena cava - thrombus, wall thickening, compression

Question 13

What are the consequences of impairment of post hepatic outflow?

Answer 13

Hepatic passive venous congestion - sinuses packed full of blood which enlarges liver - hepatomegaly
Nutmeg liver look

Question 14

Can post hepatic conditions causing passive congestion of the liver cause portal hypertension?

Answer 14

Yes - increased pressure from the blockage

Question 15

What conditions cause abnormal portal vein inflow?

Answer 15

Advanced chronic liver disease with fibrosis
Portal vein obstruction
Portal vein hypoplasia (smaller than normal)

Question 16

What signalment is associated with portal vein hypoplasia?

Answer 16

Dogs - small breeds

Question 17

Could intra/pre-hepatic conditions cause portal hypertension?

Answer 17

Yes - builds up pressure in portal system

Question 18

What hepatic conditions cause portal hypertension?

Answer 18

Post hepatic outflow conditions
Intra/pre-hepatic conditions affecting inflow

Question 19

What are the potential consequences of portal hypertension?

Answer 19

Ascites in peritoneal cavity
Acquired portosystemic shunts - make route of less resistance

Question 20

What causes of portal hypertension cause acquired portosystemic shunts?

Answer 20

Intra and pre hepatic conditions
Not usually seen in post hepatic conditions such as heart failure

Question 21

What is vacuolar hepatopathy?

Answer 21

Hepatocellular swelling and vacuolation

Question 22

What can the vacuoles contain in vacuolar hepatopathy?

Answer 22

Lipid
Water
Glycogen

Question 23

What are the gross changes associated with vacuolar hepatopathy?

Answer 23

Enlarged liver
Altered colour - pale yellow brown
Greasy - if lipid accumulation
More fragile

Question 24

What causes lipid accumulation in vacuoles in the liver?

Answer 24

Reduced hepatocellular capacity to metabolise fats
Or excess delivery

Question 25

What gross changes indicate lipid vacuolar hepatopathy?

Answer 25

Yellow/orange colour Rounder enlarged liver Floats in water rather than sinks

Question 26

What causes water accumulation in the vacuoles of vacuolar hepatopathy?

Answer 26

Cellular injury: Toxins Metabolic insults Hypoxia

Question 27

What causes glycogen accumulation in vacuoles of vacuolar hepatopathy?

Answer 27

Hyperadrenocorticism Or corticosteroid administration - steroid induced hepatopathy

Question 28

What are the 3 major patterns of necrosis in the liver?

Answer 28

Focal Zonal Massive

Question 29

What does focal necrosis of the liver look like?

Answer 29

White/grey foci randomly in the parenchyma

Question 30

What causes focal necrosis in the liver?

Answer 30

Infectious agents - bacteria, viruses, parasites etc. May be of little functional significance

Question 31

What is zonal necrosis of the liver? Where is usually affected?

Answer 31

Where a zone of the acini is affected - usually zone 3 as recieves blood last so prone to hypoxic injury Also called centrilobular or periacinar necrosis

Question 32

What causes zonal necrosis of the liver?

Answer 32

Hypoxia/ischaemia Exposure to toxins Viral infection - canine adenovirus 1

Question 33

What gross changes does zonal necrosis cause?

Answer 33

Mottles pattern to the liver

Question 34

What is massive necrosis in the liver?

Answer 34

Necrosis affecting all/majority of hepatocytes within the lobules

Question 35

What can cause massive necrosis in the liver?

Answer 35

Severe toxic injury Vitamin E/selenium deficiency in pigs

Question 36

How does hepatocellular regeneration occur if there is a focal area of necrosis but the stromal framework is retained?

Answer 36

Surviving hepatocytes proliferate within the lobule to replace lost hepatocytes

Question 37

How does hepatocellular regeneration occur if there is a focal area of necrosis AND the stromal framework collapses?

Answer 37

Fibrosis and distortion of the lobule - cant restore function Proliferation of hepatocytes in OTHER LOBULES restores hepatic mass

Question 38

How does hepatocellular regeneration occur if there is repeated episodes of necrosis?

Answer 38

Nodular regeneration with fibrosis Causes distortion of hepatic architecture

Question 39

What forms due to fibrosis in the liver? What does this cause?

Answer 39

Fibrotic tracts which contain small blood vessels Blood flows around lobules - reduced hepatic functional capacity

Question 40

What is the term for inflammation of the biliary tree?

Answer 40

Cholangitis

Question 41

What is the term for inflammation of the gall bladder?

Answer 41

Cholecystitis

Question 42

What is the term for inflammation of the biliary tree and hepatic parenchyma?

Answer 42

Cholangiohepatitis

Question 43

What are the gross features of acute hepatitis?

Answer 43

Multiple coalescing whiteish foci Multiple areas of necrosis and acute inflammation

Question 44

What can cause acute hepatitis?

Answer 44

Infectious agents Toxins/drugs

Question 45

What are some sequelae to acute bacterial hepatitis?

Answer 45

Healing and scarring - depressions in surface Chronic inflammation Abscess Septic emboli in caudal vena cava

Question 46

What is the key difference in features between acute and chronic hepatitis?

Answer 46

Fibrosis There is still inflammation and necrosis

Question 47

Where does fibrosis tend to be laid down in the liver?

Answer 47

Space of Disse - space between the hepatocytes and blood vessel endothelium Interrupts blood flow to hepatocytes

Question 48

What are some specific causes of chronic hepatitis?

Answer 48

Ragwort toxicity Copper toxicosis Idiopathic Pathogens - mycobacterium

Question 49

What are the key features of acute cholangitis on pathology?

Answer 49

Acute inflammation around bile ducts - neutrophils

Question 50

What are the key features of chronic cholangitis on pathology?

Answer 50

Chronic inflammation and fibrosis around bile ducts - lymphocytes and plasma cells Thickened bile duct walls

Question 51

What are the main causes of cholangitis/cholangiohepatitis/cholecystitis?

Answer 51

Parasites - liver fluke Bacteria - ascending infection up biliary tract Idiopathic - lymphocytic cholangitis

Question 52

What is the word for end stage liver?

Answer 52

Cirrhosis

Question 53

What are the key features of end stage liver (cirrhosis)?

Answer 53

DIFFUSE chronic changes Disturbed lobular architecture, fibrosis Disturbed hepatic vasculature - bridging

Question 54

What are two hyperplastic changes that can occur in the liver in dogs?

Answer 54

Gall bladder mucocoele Hepatic nodular hyperplasia

Question 55

What is a gall bladder mucocoele? What does it cause?

Answer 55

Hyperplastic gall bladder mucosa with extreme mucin production Can be incidental but can cause biliary obstruction/thrombi/rupture

Question 56

What is hepatic nodular hyperplasia? What does it cause?

Answer 56

Common incidental finding in older dogs - well differentiated hepatocytes in modified lobules No clinical significance

Question 57

What are the 3 potential cells of origin for primary neoplasms in the liver?

Answer 57

Hepatocellular origin Bile duct epithelium origin Mesenchymal origin

Question 58

What neoplasms are of hepatocellular origin?

Answer 58

Hepatocellular adenoma or carcinoma

Question 59

What neoplasms are of bile duct epithelium origin?

Answer 59

Cholangiocellular adenoma or carcinoma

Question 60

What neoplasms are of mesenchymal origin in the liver?

Answer 60

Haemangiosarcoma

Question 61

What do hepatocellular adenomas look like?

Answer 61

Single spherical tumour - grow by expansion

Question 62

What does hepatocellular carcinoma look like?

Answer 62

Multiple massive whitish nodules scattered through the liver

Question 63

What does a cholangiocellular carcinoma look like?

Answer 63

Single or multiple tumours where surface has a dip in it - from the bile ducts

Question 64

What are some secondary hepatic neoplasms?

Answer 64

Metastasis from: Lymphoma Pancreatic tumours Mammary tumours Haemangiosarcoma - splenic Histiocytic sarcoma

Question 65

What does lymphoma look like?

Answer 65

Can be nodular - smooth raised whitish foci over whole liver Or diffuse - mottled