Liver 1

• What is jaundice also known as?

  Icterus
• What causes jaundice in liver disease?

  The liver is unable to conjugate or excrete bilirubin
• What percentage of liver function loss is required to cause jaundice?

  Over 70%
• What is a key characteristic of the liver's ability in response to damage?

  The liver has regenerative capability

  
• What is hepatogenous photosensitivity?

  It is a condition where photodynamic substances are not removed by the liver
• How are photodynamic substances activated in hepatogenous photosensitivity?

  They are activated by UV light
• What is a consequence of the activation of photodynamic substances in the liver?

  Free radical formation and necrosis
• What areas of the body are primarily affected by hepatic encephalopathy?


  Affected areas include astrocytes
• What toxin is commonly associated with hepatic encephalopathy?

  Ammonia
• What are some clinical signs of liver disease?

  • Coagulopathies due to reduced production of clotting factors
  • Oedema and ascites from reduced albumin production
  • Superficial necrolytic dermatitis (Hepatocutaneous syndrome)

  
• What are the reactions to liver injury?

  • Regeneration: Enormous capacity (70% plus)
  • Fibrosis: Biliary, post-necrotic, diffuse, periacinar
  • Bile duct hyperplasia
  • Hallmarks of cirrhosis
• What is cirrhosis characterized by?

  Fibrosis and nodular regeneration
• What are some incidental lesions found in the liver?

  • Tension lipidosis
  • Capsule plaques or tags
  • Telangiectasis
  • Gall bladder anomalies
• What causes tension lipidosis in horses?

  It is caused by capsular tension
• What is telangiectasis in the liver?

  Localized dilation of sinusoids
• In which animals is telangiectasis commonly found?


  Common in old cats and cattle
• What are the consequences of liver displacement or rupture?

  • Diaphragm displacement and hernia
  • Torsion of a lobe (common in pigs and dogs)
  • Rupture due to trauma
• What is the most common cause of liver rupture?

  Trauma
• What is congenital melanosis?

  A condition found in calves, lambs, and piglets of no pathological significance
• What are lipopigments that affect the liver and their characteristics?

  • Ceroid and lipofuscin: yellow to brown, associated with lysosomes
  • Osmiophilic, autofluorescent, PAS +ve, and Sudan black +ve
  • Associated with storage disease and aging

  
• What does haemosiderin in the liver indicate?

  It indicates iron overload or conditions like haemolytic anaemias
• What is cholestasis?

  It is when bile flow is blocked
• What is the appearance of bile in cholestasis?

  Greenish or orange bile oozes from cut surfaces
• What are the types of bile pigmentation?

  • Cholestasis
  • Obstructive icterus
  • May be olive green to yellow
  • Birds may show green due to biliverdin
• What is iron-porphyrin?

  A black pigment associated with larval migration of Fasciola and Schistosoma spp.
• What is amyloidosis in the liver?

  It is secondary to chronic inflammation with amyloid deposited in the space of Disse
• What are the signs of reversible liver injury?

  • Cell swelling indicating acute activation of smooth ER
  • Fatty change
• What does cell swelling in the liver indicate?

  It usually indicates acute activation of smooth ER in response to drug/toxin
• What does a fatty liver look like?

  A fatty liver is tan to creamy-yellow, enlarged with rounded edges, and friable in consistency
• What are the physiological causes of fatty liver?

  • Fasting
  • Pregnancy (especially in ruminants)
  • Lactation (in cows)
• What are the pathological causes of fatty liver?

  • Genetic: Hyperlipaemia in horses and cats
  • Metabolic: Pregnancy toxaemia, ketosis, diabetes mellitus, hypothyroidism, hyperadrenocorticism
  • Deficiencies: Anaemia, choline, Cobalt/Vit B12
  • Toxicities: Phosphorus, aflatoxin, Myoporum spp.

  
• What is Ovine White Liver Disease associated with?

  Ill-thrift and photosensitivity due to cobalt/Vit B12 deficiency
• What are the changes in liver and/or hepatocyte size?

  • Atrophy: Due to shunts, malnutrition, 'portal streaming'
  • Hepatomegaly: Chronic passive congestion, cell swelling, fatty change, amyloidosis, diffuse inflammation, diffuse neoplasia

  
• What are the patterns of liver necrosis?

  • Single cell necrosis
  • Focal necrosis
  • Centrilobular necrosis
  • Midzonal necrosis
  • Periportal necrosis
  • Paracentral necrosis
  • Massive necrosis
  • Pannecrosis
• What can cause focal necrosis in the liver?

  Causes include bacterial septicaemia, viruses, and protozoa
• What is centrilobular necrosis associated with?

  Causes include hypoxia, passive congestion, and exogenous toxins
• What are the causes of zonal necrosis?

  • Various plant toxicities (dose and duration dependent)
  • E.g., ngaione from Myoporum laetum
  • In rats, lesions usually midzonal
  • Microsomal enzymes inhibited - centrilobular
  • Microsomal enzymes induced - periportal
  • Polychlorinated biphenyl (PCB) toxicity

  
• What causes periportal necrosis?

  Phosphorus poisoning and acute sporidesmin toxicity
• What are the causes of massive/submassive necrosis?

  • Serum hepatitis in horses
  • Blue-green algae toxicity in cattle (Microcystin-LR toxin)
  • Cardiac failure in pigs
  • Acute iron toxicity in piglets
  • Acute parenteral copper toxicity in calves
  • Hepatosis dietetica in pigs

  
• What is Theilers disease also known as?

  Serum hepatitis