Liver Flashcards
What congenital conditions may be found in the liver?
- Aplasia/ supernumerary lobes
- Intrahepatic cysts
- Portosystemic shunts
Describe this lesion
The entire liver parenchyma has been disrupted by disseminated fluid-filled, soft cystic structures. Areas of tissue which are not cystic show multifocal areas of haemorrhage or yellow discolouration.
Chronic disseminated severe polycystic hepatopathy
Genetic in persians
What is the difference between an intra and extrahepatic shunt?
Which structures do they arise from?
Intra - within the liver - Persistence of ductus venosus
Extra - within and outside of the liver - a direct connection between HPV and vena cava/ azygous veins
Intrahepatic shunt
Persistent ductus venosus
Extrahepatic shunt
Describe the appearance of the liver of an animal which has a porto-systemic shunt.
- Microhepatia
- Small hepatocytes
- Small or absent portal veins in triads
- More arterioles in triads
Describe this lesion
The normal anatomy of the thorax and abdomen of this cat has been severely disturbed, with the small intestine and other abdominal viscera being displaced cranially, presumably through the diaphragm.
Acute severe diffuse traumatic diaphragmatic herniation of the gastro-intestinal tract.
Outline the expected sequelae of hepatic torsion
Venous occlusion
Ischemia
Necrosis
In what situations may a liver be prone to rupture?
Trauma
Amyloidosis
Lipidosis
ie increased friability of parenchyma
Which of the zones of hepatic lobules is most vunerable to passive hyperaemia?
Zone 3 - closest to central vein
Which type of passive congestionmay be seen as an agonal change?
Acute
Describe this lesion.
Name a possible sequelae
The parenchyma of the liver shows disseminated round black lesions with non-affected tissue showing either redenning or multifocally shown to be pale tan. The surface of the liver is diffusely roughened.
Chronic disseminated severe fibrosing passive hyperaemia of the liver
Sequelae: acquired porto-systemic shunt
Chronic fibrosis of the liver leading to reduced and inadequate liver function.
Cirrhosis
What is shown here?
Possible cause?
Dilation of non-functioning tortuous vessels between the portal vein and caudal vena cava.
Due to hepatic fibrosis/ cirrhosis
Acute passive congestion due to heart failure
Teleangiectasis
Dilation of functional vessels - sinusoids in the liver
Describe this lesion
Multifocal to coelescing black irregularly shaped (3cm across) lesions can be seen on the surface of this liver and also present on the cut surface.
Acute multifocal to coelescing severe teleangiectasis of hepatic sinusoids
Irregular blood-filled cystic spaces in the liver parenchyma.
Cause?
Peliosis hepatis
Cause: focal hepatocyte necrosis
The most metabolically active hepatocytes are found where in hepatic ascini?
Zone 3 - centrolobular
Histologically how do degenerating hepatocytes appear?
Why?
- Cloudy
- Swollen
- Rounded cells
ie Hydropic degeneration
Right of the image - hydropic degeneration of hepatocytes due to influx of Na+ and H2O
Atrophy of the liver due to external pressure - neoplasia, dilated viscera etc
In which four situations can hepatic lipidosis occur?
- Nutritional - obesity/ fat rich diet
- XS FFA released from adipose due -ve energy balance
- Hypoxic lipidosis - decreased beta oxidation of fatty
- Toxic lipidosis due to decreased apoproteins
Describe this lesion
The surface and deep tissue is focally extensively pale tan, with about 80% of the hepatic tissue being affected. The tissue itself is extremely friable when touched.
Diffuse moderate subacute hepatic lipidosis
Pale yellow, greasy tissue seen with hepatic lipidosis
Vacuolation and peripherisation of hepatocyte nuclei seen with hepatic lipidosis
Which type of stain is used for visualisation of lipids in hepatocytes?
Oil red orange
What three conditions can animals be prediposed to hepatic lipidosis?
Hyperlipidaemia - DM, pancreatitis, hypothyroidism, hyperadrenocorticism, nutritional
- equine hyperlipidaemia, feline idiopathic hepatic lipidosis
Ketosis - starvation, DM, pregnancy, lactation
- Sheep; pregnancy toxaemia “twin lamb disease”
Hypoglycaemia and fatty liver syndrome in small dog breeds
How can ketosis lead to hepatic lipidosis
Increased demand for gluconeogenesis or glucose, impaired utilisation of glucose
Excessive breakdown of adipose tissue
Increased free fatty acids
Why does hyperadrenocorticism lead to hepatic lipidosis?
Action of glucocorticoids leads to:
- Decreased lipogenesis
- Increased lipolysis of adipose tissue
- Increased catabolism of skeletal muscle protein
- Increased gluconeogenesis in the liver (↑ glycogen stores)
What does this PAS stained histological slide show?
Increased glycogen storage within hepatocytes
Feathery degeneration of glycogen filled cytoplasm of hepatocytes
What can cause increased glycogen storage in hepatocytes?
Diabetes mellitus
Glycogen storage disease
Steroid induced (exogenous/endogenous)
What is amyloid?
Pathological proteinaceous substance deposited between cells (in space of Dissé and sinusoids)
AA vs SAA
Describe this lesion
Diffusely affected. The surface appears rough and yellow in colour and shows multifocal areas of haemorrhage and the liver has rounded edges suggesting enlargement.
Chronic diffuse severe necrotising hepatic amyloidosis
Amyloid depositations within sinusoids
Multifocal to coelescing moderate congenital melanosis
Increased iron uptake in birds and humans can lead to an accumulation of this substance.
What stain would be used for visualisation?
Haemosiderin - Haemochromatosis
Prussian blue
What situations can lead to accumulation of haemosiderin in hepatocytes?
- Increased iron intake
- Erythrolysis
Intoxication with which three plant types can lead to photosensitisation?
How does this work?
- St. John`s wort (Hypericum perforatum)
- buckwheat (Fagopyrum spp.)
- spring parsley (Cymopterus watsoni)
Metabolism of iron porphyrins in the liver leads to build up of photosensitive uroporphyrins = photodermatitis
Photodermatitis secondary to intoxication with iron porphyrins
Focal hepatic necrosis can be caused what aetiological agents
Herpes virus
Toxo
Disseminated pathogen
Multifocal to coelescing coagulative necrosis (preservation of tissue of architecture)
Tyzzers - Clostridium piliforme
Focally irregular area of hypereosinophilic hepatocytes with nuclear and cytoplasmic fragmentation.
Rabbit haemorrhagic disease
Describe this lesion
Disseminated round 1x1mm pale red/tan surrounded by darker red rings.
Chronic severe disseminated necrotising hepatitis
Name the three types of zonal necrosis.
- Centrolobular/ periacinar necrosis - most frequent since they are the most metabolically active cells
- Mid-zonal - rare
- Periportal - rare (occurs with biliary inflammation/ gut pathogens)
What pathogens may lead to massive (diffuse) necrosis of the liver?
- Infarct
- Pigs: vitamin E/ selenium deficiency - gall bladder oedema & mulberry heart disease
Hepatosis dietetica can be caused by what nutritional deficiency?
What does the condition lead to?
Vitamin E/ selenium deficiency
Associated with gall bladder oedema and mulberry heart disease
What is the physiological outcome of hepatic necrosis
Removal of dead hepatocytes
Regeneration of hepatic tissue - if reticular framework remains
Fibrosis with extensive injury
Central-central fibrosis - connecting central veins
Chronic congestion
Porto-central fibrosis
After centrolobular necrosis
Porto-portal fibrosis
Portal inflammation
Extensive interstitial hepatic fibrosis
Cirrhosis is characterised by what features?
- Bridging fibrosis
- Regenerative hepatocyte nodules
- Disruption of liver architecture
What gross and histological signs are present in cirrhosis of the liver?
- Extensive and diffuse fibrosis of parenchyma
- Regenerative nodules - pictured
- Lack lobular organisation
- Mitosis
- Hydropic degeneration
- Bile duct proliferation - wider bile ducts
Describe this lesion.
The liver of this dog is diffusely affected with the surface appearing rough and nighly nodular. The nodules arise due to constricting fibrosis throughout the tissue with functioning tissue remaining risen. Histologically extensive fibrosis is seen.
Chronic severe diffuse fibrosing cirrhosis.
What are the most common causes of cirrhosis?
Idiopathic
CAV-1/ Lepto infection?
Name three potential causes of cirrhosis.
- Parasitic - fluke and ascarids
- Cardiac - chronic heart failure
- Post-necrotic - toxin/ infectious agent
- Pigment
- Biliary
- Toxic
What sequelae may be expected with a case of hepatic cirrhosis?
Explain.
- Jaundice - high levels of bilirubin in the blood due to lack of processing in the liver
- lack of excretion in bile
- Ascites - portal hypertension (fibrosis)
- Hepatoencephalic syndrome - liver fails to remove ammonia from the blood
What are the major components of bile?
Water
Cholesterol
Bile salts (Na+/K+)
Bile pigments - broken down haem
What can cause PRE-HEPATIC jaundice?
Haemolysis: IMHA
Haemorrhage: bilirubin from disintegrating erythrocytes
Infectious: Leptospirosis, EIA, Bacillus anthracis
Unconjugated bilirubin would be found in which type of jaundice?
Pre-hepatic
(or hepatic with hepatocyte dysfunction)
Unconjugated bilirubin would be found in HEPATIC jaundice in which situations.
Damaged hepatocytes are not taking up bilirubin and performing conjugation
Conjugated bilirubin would be found in HEPATIC jaundice in which situation?
Severe hepatocyte swelling (hydropic degeneration?) leads to blockage of outflow from the canaliculi
Conjugated bilirubin would be found in which type of jaundice?
Explain
Post-hepatic (and hepatic with canaliculi blockage)
Due to:
- Duct obstruction - PARA, gall stones, external pressure
- Closure of excretory duct
- Fibrosis of tissue - cirrhosis
- Cholangitis
Accumulation of bile within hepatocytes (cannot see bilirubin)
Indicates cholestasis and maybe jaundice
What are seven main functions of the liver?
- Synthesis - glucose, LDLP, urea, plasma proteins
- Catabolism - lipids, ketones bodies
- Detoxification - intestinal tract, other organ
- Secretion/excretion - bile
- Carb metabolism - glycogen storage and degradation, gluconeogenesis
- Lipid metabolism - lipid degradation, cholesterol storage and degradation
- Protein metabolism - synthesis, ammonia detoxification
What clinical signs may be expected with a presentation of hepatic failure?
- Jaundice
- Hypoalbuminaemia - ascities
- Coagulopathies
- Hypoammonaemia - encephalopathy
- Portal hypertension- ascites
What histological lesions would be expected with a case of hepatic failure induced hepatic encephalopathy?
- Cerebral oedema - status spongiosus
- Neuronal necrosis and swelling
- Degeneration of astrocytes - t2 alzheimer cells
- Lacking portal veins in liver triads
Acute hepatitis is characterised by what histological signs?
Degeneration/ necrosis of hepatocytes
Leukocyte infiltration - cell type varies with infectious agent
Leukocytes within sinusoids/ kupffer cell activation with septicaemia
Cholestasis
Infiltration of sinusoids with leukocytes - septicaemia
Haemosiderin pigment depositation within cells - kupffer cells (erythrophagocytosis)
Periportal inflammation seen within acute hepatitis
Chronic hepatitis is characterised by what histological signs?
Which breed of dog may be predisposed to this condition?
Periportal lymphoplasmacytic inflammation
Progressive fibrosis
Hepatocyte apoptosis and necrosis
Predisposed: Doberman
Cholangitis
Inflammation originating from the biliary tree
What is shown in this bile duct?
Cholangitis
Pericholangitis
Triaditis
- Feline cholangitis/ cholangiohepatitis
- Inflammatory bowel disease
- Pancreatitis
Clinical disease: ascitis, jaundice, polyphagia, weight loss
What three characteristics are seen on histology of a cat with cholangitis/ cholaniohepatitis?
- Suppurative inflammation - degenerate neurophils
- Lymphoplasmacytic periportal infiltration, bile duct hyperplasia and periportal fibrosis
- Biliary cirrhosis - portoportal fibrosis, bd hyperplasia, nodular hepatic hyperplasia
What viral agents can cause hepatitis?
- CAV1 - infectious hepatitis
- EHV1
- CaHV1
- Calicivirus - rabbit haemorrhagic disease
- FCV - calici
- FIP - coronavirus
Outline the transmission and pathogenesis of CAV1
Transmission - oronasal
Pathogenesis - tonsils, LNs and lymphatics >> blood >> liver, cornea, glomerulus, vasculitis
Describe this lesion.
Multifocal to coelescing areas of black haemorrhage affecting all of the liver tissue and penetrating the parenchyma. White friable deposites are seen over the surface (fibrin). The tissue is shiney and friable to touch.
Acute (subacute) multifocal severe haemorrhagic hepatitis
Canine adenovirus 1 - infectious hepatitis
Necrotising hepatitis and intranuclear inclusion bodies associated with canine adenovirus 1 (infectious hepatitis)
Which equine herpes viruses have been implicated in viral hepatitis?
Which age group of horses is it seen in?
1 and 4()
Due to transplacental transmission it is seen in the aborted foetus (also necrosis of lungs, thymus, spleen, brain, adrenal glands)
Describe this histological lesion found in a foal
A central area of hypereosinophilic material (necrotic debris)
Areas of hyperaemia of sinusoids
Leukocytic infiltration - purple stippled nuclei
Intranuclear inclusion bodies
Acute focal severe necrotising, hyperaemic hepatitis - associated with equine herpes virus 1
Outline the mechanisms of transmission of CaHV-1.
What are the outcomes of infection?
Adult: venereal and respiratory - leads to localised replication and latent infection
Neonate: ingestion and inhalation (in utero/ fomites) - either latent infection or generalised depending on the immunocompetence
Foetus: in utero - viraemia and generalised visceral infection (death or resolution)
Which organs may be infected in a neonatal generalised infection of canine herpes virus?
Why?
The virus causes necrotising vasculitis which can affect multiple organs, eg brain, liver, kidney
Outline the mechanism of transmission of Rabbit Haemorrhagic Disease.
What is the pathogenesis?
Faecal-oral transmission
Pathogenesis - massive necrosis of the liver/ DIC
This virus specifically affects hepatocytes in the cat
FCV - systemic disease
A feline coronavirus causing granulomatous hepatitis
Feline Infectious Peritonitis - multifocal to coelescing hepatitis
Which bacterial agent is associated with rumenitis-liver abscess syndrome?
Fusobacterium necrophorum
Its a commensal in the rumen, with ruminal acidosis the mucosal lining is compromised and F. necrophorum get into blood vessels -> portal vein leading to liver infiltration
Necrobaciliosis
Describe this lesion
Multifocal to coelescing abscesses of the liver.
Raised on the hepatic surface and extending into the parenchyma (1x1 cm)
White to yellow friable material, encapsulated
Subacute multifocal-coelescing severe necrotising, suppurative hepatitis - secondary to ruminal compromise
What bacterial agent is associated with disseminated hepatitis and splenitis and spread by ticks?
Tularaemia - Francisella tularensis
Which bacterial agent is associated with abscessation of the liver in guinea pigs?
Yersinia paratuberculosis
Which leptospira species are associated with bacterial hepatitis?
Canicola
Icterohaemorrhagica
Grippotyphosa
Causes chronic hepatitis and tubular necrosis of the kidney
Outline the pathogenesis of Leptospira associated hepatitis.
Causes loss of cell-cell junctions - mitosis of hepatocytes (due to loss of cohesiveness between cells)
What agent causes Tyzzers disease?
Clostridium piliforme
Causes multifocal coagulative necrosis
Proliferation of Eimeria stiedai in the bile duct epithelium
Causes multifocal hyperplastic cholangitis and hepatitis
Parasite causing granulomatous hepatitis.
Leishmaniasis
Parasitic infection causing haemorrhagic necrotic tracts in the liver - granulomatous and eosinophilic inflammation.
Acute fascioliasis - leads to black leg, chronic fascioliasis (or resolution)
Parasitic disease causing biliary duct hyperplasia and fibrosis in chronic cases (maybe calcification).
Chronic fascioliasis
Name three cestodes than can be described as hepatophilic.
Echinococcus granulosus
Echinococcus multicularis
Taenia bovis
Milk spot liver is caused by what parasite?
Ascaris suum
Describe this lesion
Liver, multifocal to coelescing irregularly shaped white lesions. Poorly demarcated and soft to touch. 1x1cm.
Chronic multifocal to coelescing severe parasitic intersitial hepatitis
What effect do toxic substances have on the liver?
Direct oxidation, denaturation and inhibition of cellular structures
Indirect - blockage of receptors, modification of proteins
Differentials for hepatitis
Infectious - bacterial, viral - suppurative/ disseminated/ hepatic necrosis
Parasitic - multifocal tracts/ lesions
Toxic - massive to centrolobular necrosis
Toxin leading to cirrhosis, single cell necrosis and encephalomyopathy..
Pyrrolizidine alkaloidosis - ragwort
Toxin causing renal tubular casts and centrolobular necrosis in Bedlington terriers.
Copper toxicity
Aflatoxin
Apergillus flavus
A benign tumour of the liver caused by aflatoxins/ virus
Hepatic adenoma
Describe this lesion
Poorly demarcated, infiltrative, affecting only one lobe. White to grey, firm, lobulated, slightly raised.
Hepatic carcinoma
Hepatic haemangiosarcoma
