Pathology of the liver and pacreas Flashcards
Portosystemic shunt
congenital or acquired
portal blood bypasses the liver
Portosystemic shunt - congenital
shunting into vena cava, azygos or renal vein
usually a single communication between the vessels
portosystemic shunt - acquired
shunts secondary to fibrosis in older animals
multiple thin-walled shunts
Congenital cysts
most are biliary
can be multiple
displacements
congenital or acquired
tension lipidosis
focal areas of subcapsular fatty change
may relate to local ischaemia
usually the tip where it touches the diaphram
capsular fibrosis
fibrous tags are common on the surface of the liver in older horses
telangiectasis
foci of sinusoidal dilatation
cats + cattle
Circulatory disorders - passive venous congestion - presentation
usually associated with right-sided heart failure acute or chronic
Circulatory disorders - passive venous congestion - gross pathology
liver enlarged with rounded borders and oozes blood on cut surface
enhanced lobular pattern (‘nutmeg liver’)
Circulatory disorders - passive venous congestion - microscopy
hepatic venules and sinusoids engorged
periacinar areas are congested with atrophy of hepatocytes (red colour)
periportal areas undergo fatty change (pale colour)
common pigments
melanin
haemosiderin
bile
liofuscin
vacuolar hepatopathies
degenerative
hydropic change is common, non-specific and reversible
glycogen accumulation (glycogenosis) occurs in
hyperadrenocorticalism
multifocal to diffuse swelling and vacuolation of hepatocytes
enlarged pale liver in severe cases
vacuolar hepatopathies - causes
hypoxia, mild toxic damage and metabolic stress
lipidosis - causes
dietary factors: obesity and starvation
incr energy demand
disease (e.g. diabetes mellitus, ketosis and pregnancy toxaemia)
abnormal hepatocyte function that prevents fatty acids
complexing with proteins to form low density lipoproteins
Abnormal deposits and accumulations - lysosomal storage diseases
inherited deficiencies of lysosomal enzymes – neuro disease
macrophages containing stored material accumulate at multiple sites (liver, lymph nodes, central nervous system)
diagnosed by liver biopsy or post mortem examination
Abnormal deposits and accumulations - amyloidosis
substance deposited under the endothelium + basement membranes of a variety of tissues - renal glomeruli, islets of Langerhans in the pancreas + liver
primary, secondary or endocrine-associated
amyloidosis - gross appearance
Liver pale, enlarged and friable – prone to rupture
amyloidosis - microscopic appearance
homogeneous acidophilic material that shows green birefringence when stained with Congo red
Necrosis of the liver - causes
ischaemia
toxic damage
nutritional deficiencies
microbial infection
necrosis - patterns
Random: e.g. EHV-1 or salmonellosis
Zonal: e.g. ischaemia or toxic damage
Massive: e.g. hepatosis dietetica
Fibrosis of the liver - Patterns of fibrosis
Periacinar fibrosis
Biliary fibrosis
Post-necrotic scarring
Cirrhosis
Periacinar fibrosis
fibrosis surrounds central vein
chronic passive congestion
Biliary fibrosis
accompanying inflammation
centred on the portal triads
Post-necrotic scarring
following massive necrosis
cirrhosis
extensive fibrotic lesions
end stage liver
may be concurrent nodular regeneration
hepatitis - define
Inflammation of the liver parenchyma
ften caused by infection
cholangitis - define
Inflammation of the bile ducts
may be immune-mediated or associated with infection (e.g. salmonellosis in calves)
cholangiohepatitis - define
Inflammation of parenchyma and bile ducts
progression of hepatitis
necrosis, succeeded by inflammation If the animal survives then progression is: Complete resolution by regeneration Repair by fibrosis and scarring Encapsulation by abscessation Persistence by granulomatous disease