Unit 4 - Liver 2

Question 1

What does Fusobacterium necrophorum do to the liver?

Answer 1

it causes liver necrosis

Question 2

What is the pathogenesis of liver necrosis caused by Fusobacterium necrophorum?

Answer 2

1. Fusobacterium necrophorum is present in the rumen 2. Ruminal acidosis 3. Loss of ruminal mucosal integrity 4. Fusobacterium necrophorum enters portal circulation 5. Liver becomes infected 6. liver necrosis

Question 3

What microscopic pattern is observed in a liver with an ascending bacterial infection via the biliary tree?

Answer 3

there is inflammation involving the bile ducts and adjacent liver with neutrophils as an infiltrate (+/- lymphocytes and plasma cells)

Question 4

What two liver flukes are the cause of hepatic trematodosis in the United States?

Answer 4

Fasciola hepatica and Fascioloides magna

Question 5

How can liver flukes cause liver damage?

Answer 5

1. the larvae wonder through the liver for more than a month causing necrosis with eosinophils and fibrous tracts or 2. adults in the bile ducts or in cysts in the liver causing cholangiohepatitis

Question 6

What liver lesion is associated with ascarid larval migration in the pig?

Answer 6

milk spot liver - randomly scattered irregular, slightly depressed, firm, white lesions

Question 7

What typically causes hepatic necrosis?

Answer 7

hypoxia and hepatotoxins

Question 8

What gross lesions are associated with hepatic necrosis?

Answer 8

diffuse injury to a specific region of the hepatic lobule leads to an accentuated lobular pattern

Question 9

Microscopically, what does centrilobular necrosis indicate as the potential differential?

Answer 9

hypoxia or metabolized hepatotoxins

Question 10

Microscopically, what does mid-zonal necrosis indicate as the potential differential?

Answer 10

hexachlorophene or alphatoxins

Question 11

Microscopically, what does periportal necrosis indicate as the potential differential?

Answer 11

direct-acting hepatotoxins

Question 12

Microscopically, what does massive neccrosis indicate as a potential differential?

Answer 12

specific toxins or specific infectious agents

Question 13

What are some special attributes of the centrilobular region?

Answer 13

part of the lobule with the lowest oxygen tension and part of the lobule with the greatest concentration of cytochrome P-450 mixed function oxidases

Question 14

What is the most common cause of centrilobular necrosis?

Answer 14

hypoxia

Question 15

What can cause hypoxia?

Answer 15

anemia, pneumonia/pulmonary edema, passive congestion due to heart failure, or shock

Question 16

Where is the highest concentration of mixed function oxidases found?

Answer 16

in centrilobular hepatocytes

Question 17

What gross changes are seen with centrilobular necrosis?

Answer 17

you will see an accentuated lobular pattern +/- hepatomegaly

Question 18

What microscopic changes do you see with centrilobular necrosis?

Answer 18

dgeneration and loss of centrilobular hepatocytes

Question 19

What are the two major types of hepatotoxins?

Answer 19

toxins that cause direct hepatocellular injury or toxins that are transformed by liver to toxic metabolies

Question 20

Where is the expected pattern of injury to occur with toxins that cause direct hepatocellular injury?

Answer 20

periportal

Question 21

Where is the expected pattern of injury to occur with toxins transformed by the liver into toxic metabolites?

Answer 21

centrilobular

Question 22

What does carbon tetrachloride metabolize into and what does it do to the liver?

Answer 22

trihalomethane leads to oxygen free radical formation and centrilobular hepatocyte necrosis

Question 23

Where does periportal necrosis occur?

Answer 23

around vessels in portal triads

Question 24

What is periportal necrosis seen most commonly with?

Answer 24

direct-acting hepatotoxins

Question 25

Midzonal necrosis is uncommon. What species is it seen in and why?

Answer 25

it is seen in pigs and horses with aflatoxicosis and cats with hexachlorophene

Question 26

What can cause massive hepatic necrosis?

Answer 26

toxins, infectious agents, and nutrition

Question 27

What are some examples of causes of massive hepatic necrosis?

Answer 27

hepatosis dietetica (swine), blue-green algae, poisonous mushrooms

Question 28

Can the liver regenerate itself?

Answer 28

yes, when needed it has remarkable regenerative abilities by replicating mature hepatocytes and progenitor cells

Question 29

What are some consequences of severe and/or chronic injury to the liver?

Answer 29

fibrosis, biliary proliferation, or nodular regeneration

Question 30

What does fibrosis result from?

Answer 30

repetitive injury or massive necrosis with damage to ECM scaffold

Question 31

What is the process of fibrosis in the liver?

Answer 31

the activated hepatic stellate cells proliferate and produce increased extracellular matrix

Question 32

What does hepatic fibrosis represent?

Answer 32

a wound healing response to liver injury from a wide variety of etiologies

Question 33

What gross changes are associated with hepatic fibrosis?

Answer 33

irregular surface, shrunken/smaller in size, firm (fibrotic), and pale

Question 34

How does injury lead to bile duct proliferation?

Answer 34

the release of cytokines at injured limiting plates causes the bile duct to proliferate

Question 35

What can cause biliary hyperplasia?

Answer 35

biliary obstruction, periportal inflammation and fibrosis, sustained attempts at regeneration, and toxins (phomopsin, pyrrolizidine alkaloids, and aflatoxin)

Question 36

What is nodular regeneration due to?

Answer 36

the loss of the extracellular matrix and the presence of fibrosis, regeneration is typically nodular

Question 37

Why does nodular regeneration lead to diminished functional capacity?

Answer 37

regenerative nodules + fibrosis leads to an abnormal blood flow in and abnormal bile flow out

Question 38

What is cirrhosis?

Answer 38

the combination of fibrosis, biliary proliferation, and nodular regeneration

Question 39

What do the changes in a cirrhotic liver lead to?

Answer 39

distortion of the liver parenchyma, altered blood flow, and the potential development of liver failure

Question 40

What clinical issues are associated with cirrhosis?

Answer 40

ascites and hypoproteinemia

Question 41

What gross changes are seen with cirrhosis?

Answer 41

livers are smaller than normal with an irregular surface, pale in color, firm and fibrotic, and numerous nodules throughout the parenchyma

Question 42

What microscopic changes are associated with cirrhosis?

Answer 42

bridging fibrosis, nodular regeneration, biliary proliferation, +/- chronic inflammation

Question 43

What can cause cirrhosis?

Answer 43

chronic toxicity, chronic cholangitis and/or obstruction, chronic congestion, chronic inherited disorders of copper or iron metabolism, chronic hepatitis

Question 44

What agents are potentially associated with cirrhosis?

Answer 44

toxins, drugs, copper, infectious agents

Question 45

What canine breeds are predisposed to chronic hepatitis?

Answer 45

American and English cocker spaniel, West Highland white terrier, Laborador retriever, doberman pinscher, and scottish terriers

Question 46

What age dog is cirrhosis commonly found in?

Answer 46

8 year old dogs

Question 47

What are some lesions that can happen to the gall bladder?

Answer 47

cystic hyperplasia, mucocele, cholelithiasis, cholecystitis, and gall bladder distention

Question 48

What is cystic hyperplasia of the gall bladder?

Answer 48

hyperplasia of the mucosal epithelium in the gall bladder with multilobular gelatinous mucosal cysts due to the dilation of deep invaginations of surface epithelium

Question 49

What is a mucocele?

Answer 49

an abnormal, intraluminal accumulation of inspissated bile and/or mucous within the gallbladder

Question 50

What is cholelithiasis?

Answer 50

formation of stones from inspissated bile

Question 51

What is cholecystitis?

Answer 51

inflammation of gall bladder (mucosa/wall)

Question 52

What species does gallbladder cystic mucosal hyperplasia occur in?

Answer 52

dogs and sheep

Question 53

True or False: Gallbladder cystic mucosal hyperplasia is a commoon incidental aging change in dogs

Answer 53

TRUE

Question 54

Is gallbladder cystic mucosal hyperplasia a significant finding in dogs?

Answer 54

no

Question 55

What dogs seem to be predisposed to gallbladder mucoceles?

Answer 55

older, small to medium breed dogs

Question 56

What clinical signs are associated with gallbladder mucoceles?

Answer 56

vomiting, lethargy, anorexia, abdominal pain, icterus, and polyuria-polydipsia

Question 57

In the case of a gallbladder mucocele, what does serum biochemistry usually reveal?

Answer 57

increased liver enzymes

Question 58

What are some predisposing factors to mucoceles?

Answer 58

hyperlipidemias, hypothyroidism, hyperadrenocorticism, and poor gallbladder motility

Question 59

What can rupture of a gallbladder mucocele lead to?

Answer 59

peritonitis

Question 60

What is the pathogenesis of cholelithiasis?

Answer 60

bile causing supersaturation leading to precipitate leading to stones

Question 61

What is the clinical significance of cholelithiasis?

Answer 61

stones may migrate down the biliary tree and obstruct the bile duct causuing post-hepatic jaundice

Question 62

What may bile stones be made up of?

Answer 62

cholesterol, bilirubin, CaPO4, or CaCO3

Question 63

What can cause cholecystitis?

Answer 63

ascending infection from duodenum or bacteremia

Question 64

What is cholecystitis a sequela to?

Answer 64

cholelithiasis

Question 65

How does cholecystitis benefit bacteria residing in the gall bladder?

Answer 65

they allow the bacterium to escape the host immune system and allow them to be released into the intestine in bile

Question 66

What is biliary obstruction due to?

Answer 66

cholangitis, gall stones, stenosis due to scarring of the dugs, and space occupying masses compressing the common bile duct

Question 67

What is a frequent gall bladder lesion associated with anorexia?

Answer 67

distended gallbladders with viscous bile

Question 68

What are tumors and tumor like lesions are associated with the liver and biliary system?

Answer 68

nodular hyperplasia, primary neoplasms, and secondary neoplasia

Question 69

What are the more frequent/common tumors of the liver?

Answer 69

metastatic neoplasias - 2.5 times more frequent

Question 70

What primary neoplasms affect the liver and biliary systems?

Answer 70

hepatocellular neoplasms, biliary tract neoplasms, and hemangiosarcomas

Question 71

What are some primary hepatocellular neoplasms?

Answer 71

adenomas and carcinomas

Question 72

What are some primary biliary tract neoplasms?

Answer 72

adenoma (cystadenoma), and carcinoma

Question 73

What are some metastatic neoplasias of the liver and biliary system?

Answer 73

intestinal carcinoma, exocrine pancreatic carcinoma, islet cell carcinoma, splenic hemangiosarcoma, lymphosarcoma, and leukemia

Question 74

What species is nodular hyperplasia common in?

Answer 74

the dog

Question 75

What is the consistency of nodules in nodular hyperplasia?

Answer 75

they feel the same as the adjacent liver

Question 76

What do nodules from nodular hyperplasia that are lighter in color indicate?

Answer 76

they are made up of fat and glycogen

Question 77

What do nodules from nodular hyperplasia that are darker in color indicate?

Answer 77

congestion

Question 78

True or False: Nodular hyperplasia causes livers to be reduced in size

Answer 78

FALSE