Special Path Liver Diseases (viral, bacterial, toxic) Flash Cards
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)
Herpesvirus infections in nerborn or fetus (canine, equine, bovine)
Multifocal random foci of necrosis in variety of organs including liver
Feline infectious peritonitis virus may involve liver as manifestation of _____
systemic disease
Three routes bacteria can reach liver:
Blood, bile ducts, extension
Bacterial infections can cause formation of abscesses. This is common in cattle secondary to ____.
Rumenitis
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.
What route do bacteria enter the liver when causing multifocal hepatic necrosis or multifocal necrotizing hepatitis?
Hematogenous route
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
How can salmonella enter the liver besides hematogenous route?
Bile ducts
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
Three species involved with Leptospira that involves liver?
Calves, lambs and pigs
Example of fungal disease that causes hepatitis?
Histoplasmosis
Parasitic diseases - nematode migration through the liver is common but usually not significant. what lesions form?
Necrosis, inflammation, and fibrosis in localized areas
Name a nematode that migrates through the liver in swine
Ascaris suum
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.
Canine chronic hepatitis - Chronic “active” hepatitis
This is a progressive liver disease that features hepatocellular necrosis associated with infiltration of mononuclear cells and fibrosis.
Chronic “active” hepatitis is a relatively common disease entity among dogs, especially this breed.
Doberman pinschers
Advanced cases of chronic “active” hepatitis may have a _____ liver.
coarsely nodular (end-stage or cirrhotic)
Signs of chronic “active” hepatitis in dogs?
May see increase in liver enzymes, hypoalbuminemia, ascities, and coarsely nodular (cirrhotic) liver in advanced cases
Chronic lymphocytic cholangitis occurs in cats older than ___ years of age.
4
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
Cause of chronic lymphocytic cholangitis:
Unknown (may have an immunologic basis)
How can chronic lymphocytic cholangitis be differentiated from ascending infection of the biliary system?
Absence of neutrophils in chronic lymphocytic cholangitis
What are the two principal mechanisms of toxic liver disease?
(1) direct toxicity(2) conversion of a xenobiotic to a toxin
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.
Biotransformation
process of liver to metabolize/detoxify and eliminate xenobiotics