Liver Flashcards
3 Portals of Entry to the Liver
- Trauma
- Hematogenous
- Biliary (retrograde)
Hematogenous entry
typically transported from the GI tract from the portal vasculature, but can from systemic or fetal circulation
Two Big Components of Immune System in the Liver
Kupffer cells and IgA
Two Big Categories for Patterns of Injury
- Random
- Zonal
random injury appearance and origin
scattered, variably sized areas typically from a hematogenous source
Hallmark feature of zonal injury?
accentuated reticular pattern
Is zonal injury and acute or chronic process?
acute
5 Subtypes of Zonal Injury
- Centrilobular
- Paracentral
- Midzonal
- Periportal
- Bridging
What subtype of zonal injury is the most common?
centrilobular
centrilobular injury
the lowest oxygen levels, where toxins will activate when they’re broken down - MOST COMMON zonal injury pattern
causes include hypoxia and acetaminophen
periportal injury
uncommon, of hematogenous origin, usually due to DIRECT ACTING toxicants (don’t have to be broken down prior to causing injury)
Congenital Portosystemic Shunt
singular large caliber anomaly where the portal blood enters the systemic veins because it bypasses the liver
2 Types of Congenital PSS
- Intrahepatic
- Extrahepatic
Intrahepatic PSS
less common, ductus venosus, LARGE dogs
Extrahepatic PSS
much more common, seen in small breed dogs
labwork abnormalities with congenital PSS
high blood ammonia and ammonium biurate crystals in the kidney
Do congenital PSS develop portal hypertension?
no, there’s no gradient
Most common cause of impaired venous outflow/chronic passive congestion?
heart failure!
Does impaired venous outflow in the liver lead to portal hypertension?
duh
NUTMEG LIVER
sign of centrilobular/passive congestion (Note the periportal pallor)
How do animals get acquired PSS?
high portal pressure, tiny vessels dilate and become tortuous, gradient develops - this is uncommon
Telangiectasis/Peliosis Hepatitis
dilated sinusoids and blood filled spaces which is an INCIDENTAL finding in the liver (most common in cattle)
Is stenosis/lipidosis reversible?
yes
Pathogenesis of Hepatic lipidosis?
triglyceride overload without enough protein for adequate export from the liver (think anorexic fat cats)
When might you see hepatic lipidosis in a goat?
late gestation
Tension Lipidosis
an INCIDENTAL finding in cattle and horses where tension from fibrous connections collapses the sinusoids so without the blood flow the liver accumulates fat
Normal color for a liver?
mahogany
Steroid Hepatopathy
hepatocytes fill with glycogen; big brown/tan firm liver on necropsy
Can hepatocytes regenerate?
yes, quite quickly actually up to 75% and result in nodules if fibrosis occurs
stellate cell function in fibrosis
the stellate cells transform into myofibroblasts
cirrhosis
chronic diffuse process from repetitive injury and bridging fibrosis –> nodular regeneration
5 Causes of Cirrhosis
- toxicosis
- biliary disease
- chronic passive congestion
- inherited metal metabolism (copper)
- chronic hepatitis
Manifestations of Liver Failure
high blood ammonia (hepatic encephalopathy), clotting disorders, ascites, hyperbilirubinemia (icterus), cutaneous lesions
Clotting Factors affected by Liver Failure
V, VII, IX, X
Clinical Sign of Hyperbilirubinemia
icterus/jaundice
Main Sign of Acute Hepatitis
hepatocellular necrosis and suppurative exudate - NO fibrosis (obviously, it’s acute)
2 Etiologies of Chronic Hepatitis
- Persistence of infectious agent
- Persistence of antigenic stimulation
cholangitis
inflammation of cholangial LUMENS associated with fibrosis and bacterial translocation from the gut
cholangiohepatitis
inflammation is centered around cholangioles but also spreads out into hepatocytes
What virus can cause “blue eye?”
Canine adenovirus 1
blue eye is corneal edema which occurs during recovery
Herpesvirus
typically affects neonates, causes abortion; sudden multifocal necrosis (white dots)
Equine Serum Hepatitis (Theiler’s Disease) is caused by what?
flavivirus
What bacteria causes target lesions on the liver surface in sheep and goats?
Campylobacter fetus
Clostridium piliforme
known as Tyzzer’s disease, causes necrosis and stacks of intracellular filamentous bacteria!
Is tularemia zoonotic?
oh yeah, close er up
Clostridium haemolyticum
spores reside in cattle liver and then the Fascioloides flukes cause liver damage and hemoglobinuria
Is Mycobacterium bovis zoonotic?
also yes - causes large multifocal granulomatous hepatitis
Fusobacterium necrophorum
grain overload causes rumen acidosis and then it spreads to liver, abscesses form, animals die from pulmonary hemorrhage
milk spots
seen in pig livers and are caused by chronic ascarid larval migration with fibrosis
Where do mature Fascioloides hepatica live?
in the bile ducts!
Eimeria steidae
coccidia parasite in RABBITS which causes biliary hyperplasia
Results of chronic pyrrolizidine alkaloid toxicosis in cattle?
biliary hyperplasia, fibrosis, hepatomegalocytosis, photosensitization
What causes chronic aflatoxicosis?
moldy corn (Aspergillus)
Copper and Bedlington Terriers
a mutation COMMD1 causes excessive copper accumulation
Sheep and Copper
the sheep get into cattle feed, it accumulates, causes intravascular hemolysis and hemoglobinuric nephrosis
Appearance of hepatocellular carcinoma in dogs?
single mass in the left lateral liver lobe; multilobulated, gross margins
Most common liver neoplasm in cats?
cholangiocarncinoma
Most common liver metastatic neoplasm in dogs?
hemangiosarcoma
