Special Path - Liver Disease (viral, bacterial, toxins, etc.) Flashcards Preview

Anatomy > Special Path - Liver Disease (viral, bacterial, toxins, etc.) > Flashcards

Flashcards in Special Path - Liver Disease (viral, bacterial, toxins, etc.) Deck (66):
1

Infectious canine hepatitis virus

Centrilobular hepatic necrosis (may reflect ischemia) and random foci of necrosis (viral replication) and multifocal hemorrhage in other organs (tropism for endothelial cells)

2

Herpesvirus infections in nerborn or fetus (canine, equine, bovine)

Multifocal random foci of necrosis in variety of organs including liver

3

Feline infectious peritonitis virus may involve liver as manifestation of _____

systemic disease

4

Three routes bacteria can reach liver:

Blood, bile ducts, extension

5

Bacterial infections can cause formation of abscesses. This is common in cattle secondary to ____.

Rumenitis

6

How do abscesses form in cattle secondary to ruminitis in bacterial infection? How do they cause death? What is the most common bacteria?

Damage to ruminal mucosa allows bacteria (particularly Fusobacterium necrophorum) to enter portal circulation and produce focal areas of necrosis and hepatitis that develop in hepatic abscesses. If abscess encroaches on vena cava, it may result in thrombosis and passive congestion of liver, or thromboemboli in lungs. Rupture of abscess into vena cava can cause death.

7

What route do bacteria enter the liver when causing multifocal hepatic necrosis or multifocal necrotizing hepatitis?

Hematogenous route

8

Examples of bacteria that enter liver via hematogenous route, causing multifocal hepatic necrosis or multifocal necrotizing hepatitis

(1) Clostridium piliformis in foals
(2) Salmonella in many species (can enter via bile ducts)
(3) Trueperella pyogens in bovine fetus and newborn
(4) Campylobacter fetus in fetal and newborn sheep
(5) Francisella tularensis in number of animals

9

How can salmonella enter the liver besides hematogenous route?

Bile ducts

10

Liver involved in acute infection with Leptospira - ischemia to ____ areas, secondary to _____, and ____ necrosis of hepatocytes due to the presence of the organisms.

Ischemia to centrilobular areas secondary to hemolytic anemia and multifocal necrosis of hepatocytes due to presence of the organisms

11

Three species involved with Leptospira that involves liver?

Calves, lambs and pigs

12

Example of fungal disease that causes hepatitis?

Histoplasmosis

13

Parasitic diseases - nematode migration through the liver is common but usually not significant. what lesions form?

Necrosis, inflammation, and fibrosis in localized areas

14

Name a nematode that migrates through the liver in swine

Ascaris suum

15

What happens when cattle are infected with trematodes (liver flukes)? Sheep?

Flukes encyst in cattle and can cause chronic lesions but do not usually cause death. In sheep, the flukes can cause extensive liver damage and death.

16

Canine chronic hepatitis - Chronic "active" hepatitis

This is a progressive liver disease that features hepatocellular necrosis associated with infiltration of mononuclear cells and fibrosis.

17

Chronic "active" hepatitis is a relatively common disease entity among dogs, especially this breed.

Doberman pinschers

18

Advanced cases of chronic "active" hepatitis may have a _____ liver.

coarsely nodular (end-stage or cirrhotic)

19

Signs of chronic "active" hepatitis in dogs?

May see increase in liver enzymes, hypoalbuminemia, ascities, and coarsely nodular (cirrhotic) liver in advanced cases

20

Chronic lymphocytic cholangitis occurs in cats older than ___ years of age.

4

21

Chronic lymphocytic cholangitis is characterized by:

(1) Cats older than 4
(2) icterus
(3) intrahepatic cholestasis
(4) Inflammation (lymphocytes and plasma cells) in portal areas around small bile ducts
(5) Bile duct proliferation
(6) Portal fibrosis

22

Cause of chronic lymphocytic cholangitis:

Unknown (may have an immunologic basis)

23

How can chronic lymphocytic cholangitis be differentiated from ascending infection of the biliary system?

Absence of neutrophils in chronic lymphocytic cholangitis

24

What are the two principal mechanisms of toxic liver disease?

(1) direct toxicity
(2) conversion of a xenobiotic to a toxin

25

What function does the liver have in relation to xenobiotics (exogenous chemicals)?

Central role in detoxification and excretion of xenobiotics, but liver may undergo severe necrosis when exposed to them.

26

Biotransformation

process of liver to metabolize/detoxify and eliminate xenobiotics

27

Bioactivation

process of liver generating toxic intermediate metabolites (often free radicals)

28

Why may the liver undergo severe necrosis when exposed to xenobiotics?

Because of bioactivation - formation of free radicals - that are more damaging than the parent compound (xenobiotic)

29

Free radicals can react with?

DNA, RNA, and cell membranes and proteins, as well as produce oxidative stress within hepatocytes

30

What determines the site where a compound undergoes bioactivation?

the distribution of drug metabolizing enzymes within the hepatic lobule

31

What zone is the most common to injury via bioactivation? Why?

Centrilobular (zone III) since there is a relatively high concentration of mixed function oxidases (cytochrome P-450 system) responsible for biotransformation in zone III of the hepatic acinus.

32

Cytochrome P-450 system

Resides in the smooth ER of hepatocytes and is the major enzyme system of the liver for drug metabolism.
Compounds that are hepatotoxic tend to be fat soluble as the microsomal enymes convert lipophilic substances to water soluble substances for clearance.

33

What zone of the liver is cytochrome P-450 system concentrated in?

Zone III - centrilobular

34

Compounds that are hepatotoxic tend to be ___ soluble.

Fat

35

Morphology of toxin induced hepatic injury varies considerable with:

type, dose, and duration of exposure to the toxin as well as other factors (species, age, sex, diet, hormonal status, genetic constitution, etc.)

36

Acute toxic injury is characterized by: (4)

(1) Cellular swelling
(2) Fatty degeneration
(3) +/- cholestasis
(4) +/- necrosis

37

Chronic toxic injury is characterized by: (3)

(1) Fibrosis
(2) Biliary hyperplasia
(3) Hepatocellular regeneration

38

Which anticonvulsant drugs may cause chronic hepatic disease and cirrhosis in dogs? (3)

Phenobarbital, phenytoin, and primidone

39

Phenobarbital stimulates ____ of the SER in hepatocytes by:

hyperplasia - increases activity of the microsomal enzyme system

40

What species are uniquely susceptible to acetominophen toxicity since they are less efficient in converting acetominophen into non-toxic intermediates?

Cats

41

Giving acetominophen to cats can lead to ____ damage in hepatocytes and cause ____

lead to oxidative damage in hepatocytes and cause hepatic necorisis

42

Which non-steroidal anti-inflammatory drug causes idiosyncratic hepatic disease in dogs?

NSAIDs - Carpofen

43

Exogenous and endogenous glucocorticoids increase hepatic storage of glycogen by inducing _____ activity.

glyocogen sythetase

44

With glucocorticoids in dogs, typical findings in glycogen accumulation are: (3)

vacuolated hepatocytes; hepatomegaly; and an increase in serum alkaline phosphatase activity

45

Is glyocgen accumulation reversible?

Yes, after withdrawal of exogenous steroids or correction of spontaneous hyperadrenocorticalism.

46

Drug toxicity is of principal concern in ____ animals.

Small

47

Plant toxicity is of principal concern in ____ animals.

Large

48

Pyrrolizidine alkaloids are found in:

Found in many plants - senecio, crotalaria, amskinkia

49

What happens to pyrrolizidine alkaloids in the liver?

Alkaloids must be metabolized to the active form, an ester, in the hepatic P-450 system

50

Esters are ____ agents that react with cytoplasmic and nuclear constituents in hepatocytes.

alkylating agents

51

Which species of animals are most susceptible to pyrrolizidine alkaloids (plant toxicity)? Which are least affected?

Swine are most susceptible, followed by cattle, and horses, with sheep being least affected

52

Typical microscopic lesions caused by toxic plants (pyrrolizidine alkaloids for example)

Enlarged hepatocytes (megalocytes); fibrosis; bile duct hyperplasia; chronic intoxication can lead to cirrhosis and liver failure

53

Mycotoxins are ____ of fungi.

secondary metabolites

54

Aflatoxins are produced by _____ during storage feed (corn, peanuts, cotton seed) and converted to toxic _____ in SER hepatocytes.

Aflatoxins are produced by Asperigillus flavus; converted to toxic intermediate in SER hepatocyte

55

What animals are sensitive to mycotoxins?

Pigs, dogs, horses, and cattle

56

Acute toxication of mycotoxins is rare except in ____

Dogs

57

Acute toxication of mycotoxins in dogs causes:

Hemorrhage, centrilobular to massive hepatic necrosis, lipidosis, and biliary proliferation

58

Blue-green Algae blooms usually occur during what seasons?

Late summer and early fall

59

How are blue-green algae toxic?

The algae contain preformed toxins that when ingested cause zonal or massive hepatic necrosis.

60

Consequences of excess accumulation of copper in lysosomes in liver are ____ dependent.

Species - dependent

61

Copper toxicity in sheep

Copper accumulates in the liver over a period of time (dietary excess, inadequate molybdenum); necrosis of hepatocytes (multifocal) results in release of copper which leads to severe intravascular hemolysis and hepatic necrosis (centrilobular and midzonal). Lysed hemoglobin products leads to dark colored kidneys and central lobular necrosis. Urine can also be dark red.

62

CASE: Centrolobular necrosis observed in sheep --> lamb is depressed, icterus, dark red urine 2 days duration then dead. Liver has diffuse centrilobular hepatic necrosis, kidney - tubular necrosis; kidney copper levels are elevated, liver copper levels are normal

Copper toxicity

63

What terriers are prone to hereditary (autosomal recessive) disorders of copper metabolism?

Bedlington terriers and WHW terriers

64

Hereditary disorder of copper metabolism results in

Continued copper accumulation in lysosomes (hepatic levels may be 5000ppm) --> leads to ongoing multifocal necrosis of hepatocytes, chronic inflammation, fibrosis, and end stage liver

65

Is hemolysis in copper toxicity a prominent feature in dogs?

No

66

Can copper be seen in hepatocytes via histochemical staining in dogs with copper toxicity?

Yes