Hepatobiliary System 2

What is cholestasis?

Reduction in bile flow

What are the two types of cholestasis?

Intra-hepatic and extra-hepatic

Intra-hepatic cholestasis is obstruction to bile flow _________ the liver, while extra-hepatic cholestasis is obstruction _________ the liver.

Within; outside

What is hemolysis?

Breakdown of RBCs

What is the yellow pigment produced when breaking down RBCs?

Bilirubin

Bilirubin is processed in the liver during a process known as…

Conjugation

Where is bilirubin secreted?

In bile

What is accumulation of bilirubin in tissues?

Icterus/jaundice

What is the lesion associated with icterus/jaundice?

Yellow discoloration

What is accumulation of bilirubin in blood?

Hyperbilirubinemia

What are the three types of icterus/jaundice?

Pre-hepatic, hepatic, post-hepatic

Describe pre-hepatic icterus and its cause.

Increased production of bilirubin due to increased hemolysis

Describe hepatic icterus and its cause.

Impaired processing of bilirubin due to intra-hepatic cholestasis

Describe post-hepatic icterus and its cause.

Decreased excretion of bilirubin due to post-hepatic cholestasis

What liver disease leads to clinical manifestations in the nervous system due to ammonia?

Hepatic encephalopathy

Chlorophyll is broken down in the rumen into which compound?

Phylloerythrin

Phylloerythrin is processed in the liver and excreted in…

Bile

In certain liver diseases, which substance is not excreted properly?

Phylloerythrin

Phylloerythrin is photodynamic, which means…

It is activated by UV light

Phylloerythrin damages the skin once activated, especially ________ colored areas of skin.

Light

What is passive congestion of the liver?

Disturbance to liver outflow

What is one cause of passive congestion of the liver?

Cardiac dysfunction

What is the lesion associated with acute passive congestion of the liver?

Reticular pattern of lobules

What is the lesion associated with chronic passive congestion of the liver?

Nutmeg appearance of liver

What is an abnormal blood vessel that bypasses the liver?

Portosystemic shunt

What are two clinical signs of a portosystemic shunt?

Stunted growth and hepatic encephalopathy

What is the gross lession associated with a portosystemic shunt?

Hepatic atrophy (small liver)

What are the two variations of a portosystemic shunt?

Congenital and acquired

A congenital portosystemic shunt is usually how many vessels?

One

An acquired portosystemic shunt is usually how many vessels?

Many

An extrahepatic congenital portosystemic shunt is ___________ of the liver parenchyma, while an intrahepatic portosystemic shunt is ___________ the liver parenchyma.

Outside; within

Which breeds are more prone to extrahepatic congenital portosystemic shunts?

Small dog breeds

Which breeds are more prone to intrahepatic congenital portosystemic shunts?

Large dog breeds

What is the cause of hepatic lipidosis?

Excess fat within hepatocytes

What is one mechanism of hepatic lipidosis?

Excess mobilization of fat stores due to starvation

What are three gross lesions of hepatic lipidosis?

Yellow discoloration, friable texture, floats in fluid

In cases of hepatic lipidosis, hepatocytes contain…

Lipid vacuoles (fat droplets)

What disease is associated with hepatic lipidosis in obese cats?

Feline fatty liver syndrome

What are two causes of feline fatty liver syndrome?

Sudden anorexia, increased mobilization of fat stores

What disease is associated with hepatic lipidosis in high production dairy cows?

Bovine fatty liver syndrome

What are two causes of bovine fatty liver syndrome?

Onset of lactation, increased mobilization of fat stores

Excess glycogen storage is associated with which two diseases?

Diabetes mellitus and steroid hepatopathy

What are three causes of steroid hepatopathy?

Cushing’s Disease, iatrogenic (steroid administration), prolonged stress

Excess copper in the liver leads to…

Hemolysis

Which species is very sensitive to copper toxicosis?

Sheep

What is the lesion associated with copper toxicosis in sheep?

Gun-metal black kidneys

What dog breed is sensitive to copper toxicosis due to genetic defect?

Bedlington terrier

What are three routes of entry of infectious disease in the liver?

Hematogenous (bloodstream), ascending (bile ducts), direct extension (abdomen)

Where do adult nematodes/roundworms live?

Pig intestines

Larvae nematodes/roundworms migrate through the liver, leading to which gross lesion?

Milk spots (fibrosis)

Cestode/tapeworms in the liver lead to which disease?

Hydatid liver disease

Where do adult cestodes/tapeworms live?

GI tract of dogs

Where do the larvae of cestodes/tapeworms live? What do they form?

Sheep liver - form hydatid cysts

Where do adult liver flukes (trematode/flatworm) live?

Bile ducts of sheep and cattle

Where do the larvae of liver flukes (trematode/flatworm) migrate through? What do they cause?

Hepatic parenchyma - cause necrosis

What animal is affected by histomoniasis (blackhead)?

Turkey

What organism/species causes histomoniasis (blackhead)?

Histomonas protozoa

Histomonas eggs are transmitted in the eggs of…

Nematodes of chickens

Nematode larvae containing Histomonas penetrate which species?

Earthworm

What are the lesions associated with histomoniasis/blackhead?

Target-like areas of necrosis

What are the two viruses associated with liver infection?

Canine adenovirus-1 and herpesvirus

What are hepatic abscesses? How do bacteria get to the liver?

Pus-filled nodules; bacteria travel from GI tract via portal vein

What is multifocal necrotizing hepatitis? What is it associated with?

Multifocal areas of necrosis; sepsis

Hepatic granulomas are associated with nodules of…

Macrophages

What bacteria cause black disease?

Clostridium novyi

Describe the pathogenesis of black disease.

Liver injury from migrating flukes → anaerobic environment → spore germination → toxin release → liver necrosis

What non-neoplastic liver nodules are age-related, common in older dogs?

Nodular hyperplasia

What pattern is present on histology of a liver with nodular hyperplasia?

Lobular pattern

What non-neoplastic liver nodules are not age-related and form in response to loss of hepatocytes?

Regenerative nodules

Describe the gross lesions associated with regenerative nodules.

Nodules surrounded by fibrosis

What pattern is present on histology of a liver with regenerative nodules?

Lobular pattern lost

What is the end stage of regenerative nodules?

Cirrhosis - lots of fibrosis

Hepatocellular adenoma is…(benign/malignant)

Benign

Hepatocellular carcinoma is…(benign/malignant)

Malignant

Are dogs or cats more susceptible to hepatocellular tumors?

Dogs

Describe the gross lesions associated with hepatocellular tumors.

Solitary mass

Cholangiocellular adenoma and carcinoma are known as _______ tumors.

Biliary

Cholangiocellular adenoma is…(benign/malignant)

Benign

Cholangiocellular carcinoma is…(benign/malignant)

Malignant

Are dogs or cats more susceptible to biliary tumors?

Cats

Describe the gross lesions associated with biliary tumors.

Multifocial, umbilicated masses

The gallbladder stores, concentrates, and releases…

Bile

Which species does not have a gallbladder?

Horses

Choleliths (gallstones) are not significant unless…

They cause an obstruction