PATHOLOGY - Patterns of Liver Disease Flashcards
What are the three zones of a hepatic lobule?
- Periportal
- Midzonal
- Centrilobular
Which zone of the hepatic lobule is most vulnerable to hypoxic and toxic injury?
Centrilobular region
List the six functions of the liver
- Bilirubin metabolism
- Bile acid metabolism
- Lipid metabolism
- Xenobiotic (foreign substance) metabolism
- Protein synthesis
- Immune function
List the eight different methods of liver disease/injury
- Vascular
- Inflammatory (infectious, immune-mediated)
- Trauma
- Anomaly
- Metabolic
- Idiopathic
- Neoplastic
- Degenerative
What is icterus?
Another term for jaundice
Where in the body is it easiest to see jaundice/icterus? Why is this?
The oropharynx and the sclera of the eye as bilirubin has a higher affinity for elastic tissue
How much bilirubin is required to classify hyperbilirubinaemia?
0.5mg/dl
How much bilirubin is required to see icterus/jaundice?
2mg/dl
How long does it take for there to be maximum accumulation of bilirubin in the body?
2 days
What are the classifications of hyperbilirubinaemia?
- Pre-hepatic hyperbilirubinaemia
- Hepatic hyperbilirubinaemia
- Post-hepatic hyperbilirubinaemia
What is the cause of pre-hepatic hyperbilirubinaemia?
Haemolysis
What are the potential causes of hepatic hyperbilirubinaemia?
- Decreased functional hepatic mass
- Intra-hepatic cholestasis
- Anorexia/fasting (especially in horses)
What are the potential causes of post-hepatic hyperbilirubinaemia?
- Obstructive extra-hepatic cholestasis
- Biliary adenoma or cholangiocellular carcinoma (biliary tumours)
- Cholelithiasis (gall stones)
What is cholestasis?
The impairment or stop of bile flow
What are the possible causes of cholestasis?
- Impaired bile secretion from hepatocytes
- Obstruction of the intra- or extra-hepatic bile ducts
What is hepatic regeneration?
Replication of mature hepatocytes and an increase in the size of pre-existing hepatic lobules
What is required during hepatic regeneration to prevent fibrosis and the formation of hepatic nodules?
The basement membranes supporting hepatocyte arrangement within hepatic lobules
What does centrilobular fibrosis indicate about the aetiology of the injury?
Centrilobular fibrosis indicates chronic toxicity or anaemia
What does periportal fibrosis indicate about the aetiology of the injury?
Periportal fibrosis indicates chronic inflammation
Describe the appearance of cirrhosis
- Nodulated due to attempted hepatic regeneration
- Scarring and firm due to fibrosis
List five possible causes of cirrhosis
- Chronic toxicity
- Chronic cholingitis
- Chronic cholestasis
- Chronic hepatitis
- Idiopathic
What is cholangitis?
Inflammation of the bile duct system
What is hepatitis?
Inflammation of the liver
What is the main consequence of cirrhosis?
Liver failure
List five of the other consequences of cirrhosis
- Hepatic encephalopathy
- Hyperbilirubinaemia
- Coagulation disorders
- Panhypoproteinaemia
- Portosystemic shunting
List the three main ways disease inducing agents enter the liver
- Direct entry
- Haematogenous (carried by the blood)
- Retrograde biliary transport
List the six hepatic defences against disease
- Skin
- Ribcage
- Omentum
- Kupffer cells
- IgA antibodies in the billary tree
- Terminal sphincter of the billary tree
Which disease causes are indicated by focal hepatic lesions?
- Neoplasia
- Vascular
- Trauma
Which disease aetiologies are indicated by random, multifocal hepatic lesions?
- Metastatic neoplasia
- Infection
- Hyperplasia
Which disease aetiologies are indicated by diffuse hepatic lesions?
- Toxins
- Hypoxia
- Metabolic disease
- Degenerative disease
Give examples of neoplastic focal liver disease
- Hepatocellular adenoma
- Hepatocellular carcinoma
- Billary adenoma
- Cholangiocellular carcinoma
- Carcinoid
Why is infarction of the liver very rare?
Due to the dual blood supply from the hepatic portal vein and the hepatic artery
What is most likely to cause vascular damage to the liver?
Torsion of the liver lobes
In which species is hepatic nodular hyperplasia most common?
Dogs
Which metastatic neoplasia is most commonly found on the liver?
Metastatic lymphoma
List three examples of viruses which directly attack the liver
- Herpesviruses
- Infectious canine hepatitis
- Rabbit haemorrhagic disease virus
Which disease directly attacks the liver causing haemorrhage and hepatocyte displacement?
Leptospirosis
List the two main haematogenous causes of liver abscesses in cattle
- Secondary to rumenitis
- Secondary to omphalitis
Give a specific example of a trematode parasite which causes disease within the liver
Fasciola hepatica (liver fluke)
How long does it take the liver to look histologically normal after a single non-lethal insult?
1 week
What is the result of single/multiple lethal hepatotoxic insults?
Hepatic necrosis
What is the result of chronic hepatotoxic insult?
Fibrosis and eventual cirrhosis
What are the possible causes of hypoxic damage to the liver?
- Anaemia
- Congestive heart failure
On gross examination, what would be the early sign of hepatic hypoxia?
Yellow centrilobular areas
On gross examination, what would be the signs of severe/chronic hypoxia of the liver?
Red centrilobular areas (haemorrhage and necrosis) and yellow periportal areas
On gross examination, what would be the appearance of a liver with hepatic amyloidosis?
- Yellow
- Waxy
Why should you not take a biopsy of a liver that is suspected to have hepatic amyloidosis?
Because livers suffering from hepatic amyloidosis are prone to rupture and haemorrhage
