C13 Hepatobiliary Pathology II Flashcards
Hepatitis definition
- pattern depends on what
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
Acute hepatitis: usually a mix of
inflammation, apoptosis/necrosis, regeneration
Chronic hepatitis:
- consistent feature
- definition
- causes
- progression
- signs
- 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
Chronic hepatitis in dogs
- how common
- causes
- stain, assessment
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
Chronic hepatitis in dogs: copper
- what mutation, breed
- presentation
- progression
- other breeds?
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
Chronic hepatitis in other species
- copper possible in cats?
- causes
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
Cholecystitis
- common?
- cause?
- predisposition
- type in calves and cause?
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
Cholangitis
inflammation of the biliary tree
Cholangiohepatitis
- cause?
- progression
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
Cholangitis in cats
- types:
> causes, presentations
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
Cholelithiasis
- form where, from what
- effects?
- 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
more common causes of biliary obstruction
- Biliary obstruction is more commonly due to inflammation
o Occasionally, ducts can be compressed by tumours, etc.
can we get jaundice from blockage of main bile duct? what about smaller ducts? why?
- Blockage of the main bile duct leads to jaundice, but not blockage of smaller ducts (the rest of the liver compensates)
what happens if biliary tract ruptures
- 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
viral causes of multifocal hepatic necrosis
adenoviruses, influenza, herpesvirus in neonates
viral causes of lymphohistiocytic hepatitis and apoptosis
porcine circovirus 2
viral causes of granulomatous hepatitis in cats
o Granulomatous hepatitis: feline coronavirus (feline infectious peritonitis)
do many viruses directly target the liver?
no
Rabbit haemorrhagic disease (calicivirus)
- geography
- historic use
- symptoms
- prevention
- reportable?
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!
Infectious canine hepatitis
- agent
- prevention
- presentation
- spread
- cells affected
- lesions, signs
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
Equine serum hepatitis
- linked to what pathogen
- sympotms
- usually seen when?
- symptoms
- liver appearance
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’)
clinical significance of bacterial hepatitis
- Bacterial hepatitis is common but usually focal and not clinically significant
will sustained bacteremia form liver lesions?
- Almost every sustained or repeated bacteremia will form liver lesions
bacteria that can cause inflammatory liver in all species
Salmonella, Mycobacteria
Hepatic abscesses
- common in what animals
- sequel to what
- consequences
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
Hepatic necrobacillosis
- agent
- secondary to what
- appearance
Fusobacterium necrophorum
o Secondary to omphalitis or rumenitis, produces a leukotoxin
o Multifocal dry areas of coagulative necrosis surrounded by hemorrhage
Leptospirosis
- disease presentation
systemic disease with acute jaundice, cholestasis, renal failure
Infectious hepatitis (black disease)
- agent
- pathogenesis
- prevention
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
Bacillary haemoglobinuria
- species
- agent
- pathogenesis
- lesions, signs
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
Clostridium piliforme
- disease, species
- lesions
- Dx
- foals presentation
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
signs of migrating larvae in the liver
Migrating larvae cause physical damage (hemorrhage, necrosis, inflammation)
o Look for eosinophils
o Healing via fibrosis
o Sometimes trapped larvae form eosinophilic granulomas
flukes in the liver have what characteristic trait
Several species of trematodes (flukes) specifically infect the liver
o Characteristic black pigment
Fasciola hepatica
- possible consequences
- lesions
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
Dicrocoelium dendriticum
- what is it
o Similar to F. hepatica but milder
o Land snails and ants in life cycle
Fascioloides magna
- natural host
- anatomic home
- effects in different animals
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
Eimeria stiedae
- species
- anatomic infection location and pattern
o Significant pathogen of (meat) rabbits, infects bile ducts (multifocal nonrandom)
liver ‘abscess’ may be what parasite class?
o Tapeworm cysts (beware the ‘abscess’!)
