General Concepts in Hepatobiliary Disease Flashcards
what does the lobular model divide the liver lobes into?
centrilobular
midzonal
periportal
what makes up bile?
bile salts
bilirubin
cholesterol
protein
fatty acids
phospholipids
what can cause hyperbilirubinemia?
pre-hepatic
hepatic cholestasis
post-hepatic cholestasis
what are the consequences of cholestasis?
failure to excrete cholesterol into bile
fat malabsorption
retain cytotoxic substances
increased toxicity of drugs normally excreted in bile
will bile acids increase or decrease with liver disease?
increase
when does hypoglycemia occur with liver disease?
severe liver disease: acute liver failure
congenital portosystemic shunt dogs
why does BUN decrease and ammonia increase with severe liver disease or a congenital portosystemic shunt?
loss of urea cycle function
when does hepatic encephalopathy occur?
portosystemic shunts
acute liver failure
end stage (fibrotic) liver
where is albumin made?
only liver
when might vitamin K absorption be impaired?
cholestasis
what can cause prehepatic portal hypertension?
portal vein thrombosis
what leads to multiple acquired portosystemic shunts?
persistent portal hypertension: opening of embryonic vessels
collateral circulation direct into systemic circulation
what is the mechanism of ascites due to portal hypertension?
increased interstitial fluid
overwhelms lymphatics
what is fine needle aspirate more useful for?
diffuse disease: hepatocyte vacuolization or neoplasia (lymphoma)
what is the least invasive type of biopsy?
ultrasound guided needle biopsy
what are the pros of laparotomy?
no special equipment
can visualize most regions of liver
can remove lobectomy for larger masses or abscesses
what can cause glycogen deposition?
steroids: cortisol
in whom is lipid accumulation most common?
cats
ruminants
ponies
ferrets
diabetic dogs, toy puppies
what stains lipid accumulation?
oil red O
what type of inflammation/cellular infiltrates do most bacteria cause?
neutrophils
what is the most common zonal lesion?
centrilobular necrosis
what is hepatitis?
inflammation of liver: hepatocytes
what is cholangitis?
inflammation of bile ductules
what are the sequelae of injury?
regeneration
bile duct hyperplasia
fibrosis
end stage liver/cirrhosis
how much of the hepatic blood flow is from the arterial circulation?
30%
hepatic artery
what is the reserve and regenerative capacity like of the liver?
tremendous: can remove 75% in healthy animal
what are the functions of the periportal zone?
gluconeogenesis
oxidation of fatty acids
ureagenesis
what are the functions of the centrilobular zone?
drug metabolizing enzymes
glycolysis
liponeogenesis
what cells are in the lobules?
hepatocytes, sinusoidal endothelium
kupffer cells
stellate (ito) cells
what is the enterohepatic circulation?
bile acids actively absorbed in ileum
delivered to portal circulation
actively taken up by hepatocytes from sinusoidal surface
re-secreted into canaliculi
what causes hepatic cholestasis?
loss of hepatic mass
obstruction of canaliculi
sepsis: interference with transporters
why is there an increase in bile acids with liver disease?
shunting
failure of removal from portal circulation
why might you see hypoglycemia with severe liver disease?
decreased insulin clearance
decreased hepatic gluconeogenesis
if there is hepatic atrophy or cirrhosis, should cholesterol go up or down?
down: loss of ability to make lipoproteins
what can you treat hepatic encephalopathy with?
low protein diet
antibiotics to change bacterial flora
lactulose: changes flora and pH
which globulins are not made in the liver?
immunoglobulins
what with clotting is a poor prognostic indicator with liver disease?
elevated PT/PTT
what can cause intrahepatic portal hypertension?
end-stage liver
granulomatous inflammation
arteriovenous shunts
what can cause posthepatic portal hypertension?
occlusion at hepatic veins, vena cava, right heart
congestive heart failure: especially right
constrictive pericarditis
in whom is ascites due to portal hypertension common?
dogs and cats
rare in horses and cattle
what causes primary photosensitization?
ingest preformed photodynamic agents
which biopsy has the highest risk of being non-diagnostic?
ultrasound guided needle biopsy
which biopsy method is associated with higher patient mortality?
laparotomy
what makes taking a biopsy contraindicated?
coagulation disorder
hepatic abscess or vascular tumor
what is vacuolation due to glycogen like?
indistinct, hazy vacuolation
what causes hydropic degeneration?
reverible cell injury: decreased ATP, influx of water, cellular swelling
what is lipofuscin?
wear and tear: fine, tan granules in hepatocytes
is hemosiderin normal in hepatocytes?
small amounts normal
what can be used to stain for copper?
rhodanine
what are some connective tissue stains?
trichrome
reticulin silver
sirius red
what type of cellular infiltrates are seen with Salmonella?
lymphocytes
macrophages
what is choledochitis?
inflammation of common bile duct
what percentage of the body weight in dogs/cats is made up of the liver?
3-4%
how much of the hepatic oxygen is provided by the hepatic artery and how much by the portal circulation?
50% by each
what do stellate/ito cells do?
fat soluble vitamin storage
transform into myofibroblasts to contribute to fibrosis
what cells are at the junction?
oval cells: bipotential stem cells
what is a pre-hepatic cause of hyperbilirubinemia?
increased red cell breakdown
why is hypoglycemia seen with congenital portosystemic shunts?
atrophied liver with poor glycogen stores
when might globulins be low?
severe loss of functional mass
what are some causes of portal vein thrombosis?
local inflammation
hypercoagulable state
secondary to tumor emboli
what is seen in an end stage liver that leads to intrahepatic portal hypertension?
fibrosis
nodular regeneration
capillarization of sinusoids
what contributes to gastric ulceration?
portal hypertension: relative ischemia
bile acids cytotoxic
increased gastric levels?
what is seen with hepatocutaneous syndrome?
erosions and ulceration of muzzle, pressure points, mucocutaneous junctions
what accumulates in skin in photosensitization?
photodynamic substance
what is inherited porphyria?
defects in hemoglobin synthesis
what are some rare complications of a liver biopsy?
infections
perforation of gallbladder
pneumothorax
vasovagal response
is it expected to see bile in a biopsy?
no
what is interface necrosis/apoptosis usually seen with in dogs?
idiopathic hepatitis
