C13 Hepatobiliary Pathology II

Question 1

Hepatitis definition
- pattern depends on what

Answer 1

Hepatitis: presence of inflammatory cells and/or infectious agents in the parenchyma, focal or diffuse
o Pattern of inflammation depends on the cause, but most infectious agents produce patchy lesions that don’t cause hepatic insufficiency

Question 2

Acute hepatitis: usually a mix of

Answer 2

inflammation, apoptosis/necrosis, regeneration

Question 3

Chronic hepatitis:
- consistent feature
- definition
- causes
- progression
- signs

Answer 3

• Chronic hepatitis: fibrosis is a consistent feature
  o Chronic necroinflammatory disease lasting more than 6 months
  o Idiopathic most common but also bile obstruction, infection, toxins, etc
  o Does not progress to cirrhosis or severe fibrosis unless protracted damage
  o Nonspecific signs initially, then typical liver insufficiency

Question 4

Chronic hepatitis in dogs
- how common
- causes
- stain, assessment

Answer 4

o Common
o Most cases idiopathic, but copper accumulation is a well known cause
o Copper regulated primarily via biliary excretion
o < 400 μg/g normal, > 1,800-2,000 μg/g pathogenic
o Can stain with rhodanine but biochemical assessment is more reliable

Question 5

Chronic hepatitis in dogs: copper
- what mutation, breed
- presentation
- progression
- other breeds?

Answer 5

o COMMD1 mutation in Bedlington terrier: impaired copper excretion
o Autosomal recessive, presents with progressive liver failure
o Can develop hemolytic crisis if copper released into systemic circulation
o Other predisposed breeds (defects unknown): Labrador, Doberman, Westie, English and American cocker spaniel, Skye terrier, standard poodle, Dalmatian, English springer spaniel

Question 6

Chronic hepatitis in other species
- copper possible in cats?
- causes

Answer 6

o Copper-associated hepatitis also reported in cats
o Usually associated with toxin ingestion in herbivores but the lesions are nonspecific, so it is difficult to determine a precise cause

Question 7

Cholecystitis
- common?
- cause?
- predisposition
- type in calves and cause?

Answer 7

Cholecystitis: inflammation of the gallbladder (uncommon)
o Bacterial reflux via ducts or hematogenous
o Choleliths (stones) or parasites predispose
o Fibrinous cholecystitis in calves with salmonellosis

Question 8

Cholangitis

Answer 8

inflammation of the biliary tree

Question 9

Cholangiohepatitis
- cause?
- progression

Answer 9

Cholangiohepatitis: inflammation centred on the biliary tract and extending into the parenchyma (more common than cholangitis)
o Usually ascending bacterial infection from gut (bile stasis)
o Rarely descending infection (cattle with hepatic abscesses)
o Can rapidly cause death via septicaemia but chronic inflammation more common
o Chronic inflammation leads to fibrosis and biliary proliferation

Question 10

Cholangitis in cats
- types:
> causes, presentations

Answer 10

Neutrophilic: common, part of ‘triaditis’ (inflammatory bowel disease,
pancreatitis, cholangitis) and with bile obstruction
o Ascending bacteria, mostly E. coli
o Neutrophils in the acute stage and later periportal hepatocellular necrosis
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Lymphocytic: slowly progressive, lymphoid infiltrates and portal fibrosis
o Believed to be immune-mediated

Question 11

Cholelithiasis
- form where, from what
- effects?

Answer 11

• Cholelithiasis: usually form in gallbladder, mix of cholesterol, bile pigment, salts
  o Rare in animals, usually asymptomatic but can block ducts
  o Large stones can cause pressure necrosis of mucosa

Question 12

more common causes of biliary obstruction

Answer 12

• Biliary obstruction is more commonly due to inflammation
  o Occasionally, ducts can be compressed by tumours, etc.

Question 13

can we get jaundice from blockage of main bile duct? what about smaller ducts? why?

Answer 13

• Blockage of the main bile duct leads to jaundice, but not blockage of smaller ducts (the rest of the liver compensates)

Question 14

what happens if biliary tract ruptures

Answer 14

• If the biliary tract ruptures, the omentum can’t block the hole and bile leaks
  o Even if sterile, severe irritation (bile peritonitis), can be rapidly fatal

Question 15

viral causes of multifocal hepatic necrosis

Answer 15

adenoviruses, influenza, herpesvirus in neonates

Question 16

viral causes of lymphohistiocytic hepatitis and apoptosis

Answer 16

porcine circovirus 2

Question 17

viral causes of granulomatous hepatitis in cats

Answer 17

o Granulomatous hepatitis: feline coronavirus (feline infectious peritonitis)

Question 18

do many viruses directly target the liver?

Answer 18

no

Question 19

Rabbit haemorrhagic disease (calicivirus)
- geography
- historic use
- symptoms
- prevention
- reportable?

Answer 19

o Endemic in UK, Europe; sporadic outbreaks in North America
o Deliberately used as pest control in Australia
o Sudden death with no signs or anorexia +/- hemorrhages, neurological signs
shortly before death, all have hepatic necrosis and inflammation
o Vaccine used in pets but not available here
o REPORTABLE DISEASE!

Question 20

Infectious canine hepatitis
- agent
- prevention
- presentation
- spread
- cells affected
- lesions, signs

Answer 20

Infectious canine hepatitis: canine adenovirus 1 (now rare due to vaccination)
o Often subclinical, if severe case vomiting, abdominal pain, +/- jaundice
o Oronasal spread, replicates in tonsils (may cause tonsillitis)
o Virus targets endothelium and hepatocytes: centrilobular necrosis
o Connective tissue is intact so liver can regenerate
o Lesions in other organs (hemorrhages) are related to endothelial damage
o Recovering cases have corneal edema (‘blue eye’) due to type III sensitivity

Question 21

Equine serum hepatitis
- linked to what pathogen
- sympotms
- usually seen when?
- symptoms
- liver appearance

Answer 21

Equine serum hepatitis: linked to Theiler’s disease- associated virus (flavivirus)
o Common cause of acute hepatic failure in horses
o Usually seen after passive immunization but some
outbreaks unrelated to this
o Long incubation period (42-60 days) but sudden
clinical onset, death in 6-24 hours
o Lethargy, jaundice, photosensitivity, mania,
blindness, ataxia, sudden death
o Small, flaccid liver due to loss of cells (‘dishrag liver’)

Question 22

clinical significance of bacterial hepatitis

Answer 22

• Bacterial hepatitis is common but usually focal and not clinically significant

Question 23

will sustained bacteremia form liver lesions?

Answer 23

• Almost every sustained or repeated bacteremia will form liver lesions

Question 24

bacteria that can cause inflammatory liver in all species

Answer 24

Salmonella, Mycobacteria

Question 25

Hepatic abscesses
- common in what animals
- sequel to what
- consequences

Answer 25

Hepatic abscesses: most common in feedlot cattle +/- sheep, single or multiple
o Often not found until slaughter, common sequel to rumenitis
o Variable possible consequences…
§ Can form adhesions
§ Can rupture into hepatic veins,
producing thrombosis and emboli
§ Really large emboli can be fatal
o May also contain fungi

Question 26

Hepatic necrobacillosis
- agent
- secondary to what
- appearance

Answer 26

Fusobacterium necrophorum
o Secondary to omphalitis or rumenitis, produces a leukotoxin
o Multifocal dry areas of coagulative necrosis surrounded by hemorrhage

Question 27

Leptospirosis
- disease presentation

Answer 27

systemic disease with acute jaundice, cholestasis, renal failure

Question 28

Infectious hepatitis (black disease)
- agent
- pathogenesis
- prevention

Answer 28

Cows, sheep
- vaccine
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Clostridium novyi type B
- spores in soil ingested, cross mucous membranes
> Live in Kupffer cells
> Flukes > Necrosis causes anaerobic conditions
> Spores activate, produce necrotizing toxins
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- Acute, fatal disease – unexpected deaths
- Congested SQ vessels (hence ‘black’)
- Rapid decomposition
- Abdominal fluid clots on exposure to air
- Yellow-white liver necrosis with red rim

Question 29

Bacillary haemoglobinuria
- species
- agent
- pathogenesis
- lesions, signs

Answer 29

Cows, sheep
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Clostridium haemolyticum
o Similar pathogenesis to black disease, mostly seen in areas with flukes
o Affects cattle and sheep, similar hepatic lesions to black disease (usually bigger)
o Intravascular hemolysis, anemia, hemoglobinuria
o Red-brown kidneys due to hemoglobin, port wine colour urine

Question 30

Clostridium piliforme
- disease, species
- lesions
- Dx
- foals presentation

Answer 30

Tyzzer’s disease of rodents, dogs, cats, foals, calves
o Focal hepatitis and necrosis (pale foci up to a few millimetres)
o Hard to culture, confirmed by finding organisms at the periphery of necrosis
o In foals, deaths between 1-4 weeks old, often found dead after short illness

Question 31

signs of migrating larvae in the liver

Answer 31

Migrating larvae cause physical damage (hemorrhage, necrosis, inflammation)
o Look for eosinophils
o Healing via fibrosis
o Sometimes trapped larvae form eosinophilic granulomas

Question 32

flukes in the liver have what characteristic trait

Answer 32

Several species of trematodes (flukes) specifically infect the liver
o Characteristic black pigment

Question 33

Fasciola hepatica
- possible consequences
- lesions

Answer 33

o Larvae migrate through liver, can
cause fatal anemia in heavy infection
o Don’t forget about black disease!
o Adults live in bile ducts, causing
dilation and fibrosis

Question 34

Dicrocoelium dendriticum
- what is it

Answer 34

o Similar to F. hepatica but milder
o Land snails and ants in life cycle

Question 35

Fascioloides magna
- natural host
- anatomic home
- effects in different animals

Answer 35

o Natural host is deer, lives in parenchyma and connects with bile ducts
o In cows, migrates briefly, no connection to bile ducts
o In sheep, never stops migrating – small burdens are deadly

Question 36

Eimeria stiedae
- species
- anatomic infection location and pattern

Answer 36

o Significant pathogen of (meat) rabbits, infects bile ducts (multifocal nonrandom)

Question 37

liver ‘abscess’ may be what parasite class?

Answer 37

o Tapeworm cysts (beware the ‘abscess’!)