Liver 2 (test 1) Flashcards
What is the most sensitive measure of hepatic function?
Serum bile Acids
Serum bile acids are useful for detecting 2 particular liver related issues, what are they?
portosystemic shunts and detecting liver disease in non-icteric patients
Normal levels of serum bile acids require what?
- functional hepatocytes with normal blood flow 2. unimpaired bile flow 3. good portal circulation
What are consequences of dysfunction in relation to bile secretion?
- Hyperbilirubinemia and Icterus 2. malabsorption of fat and fat soluble vitamins (ADEK) 3. Failure to eliminate toxins normally excreted in bile (endotoxins, bilirubin, phylloerythrin, etc)
What is Bilirubin a product of?
It is a catabolic product of hemoglobin (also myoglobin)
Conjugated bilirubin is the pigment of bile, while bile acids are the key component
What is the route of production and excretion for bilirubin?
It is bound by albumin–>carried to liver–>removed from plasma by hepatocytes–>conjugated and excreted in bile
Unconjugated hyperbilirubinemia is rare, except in what species?
HORSES, you can see a mild icterus with anorexia
What deconjugates bilirubin in the gut?
Bacteria degrade it into urobiliogens–>residue of intact pigments that are excreted in the feces (brown poop)
What are 3 general causes of hyperbilirubinemia?
-
Pre-hepatic (hemolytic-autoimmune)=increased production
- decreased PCV & RBC’s -
Primary Hepatic (injury to hepatocytes and/or bile flow IN liver)
- impaired uptake, conjugation, and/or secretion=liver disease -
Post-Hepatic (obstructive)
- Inhibition of outflow from liver (impaired excretion to SI)=Common bile duct disease
Define Cholestasis
It is the reduction of bile flow
-if long standing, the bile acids in bile will damage cell membranes and there will also be evidence of hepatocyte damage (increased leakage and induced enzymes)
What is Extrahepatic cholestasis? What are some examples?
Extrahepatic cholestasis=Obstructions resulting in decreased bile flow
Examples:
- Tumors
- Calculi (choleliths=bile stones) most common
- inflammation and/or fibrosis
- parasites (liver flukes)
- pancreatic lesions (notably in dogs and cats)
What are choleliths?
They are concretions formed from constituents of bile (stones)
What are 3 causes of intrahepatic cholestasis?
More common in veterinary medicine
- Diffuse hepatocellular damage: decreased uptake, conjugation, or secretion
- anything that damages hepatocytes is likely to injure the membrane and enzymes of the secretory apparatus - Lesion that causes hepatocellular swelling leading to occulsion of the canaliculi and impede intrahepatic bile flow (hepatic lipidosis=kitty cats)
- Cholangitis/Cholangiohepatitis: inflammatory processes centered around the biliary tree
- inflamation and fibrosis around the biliary tree can block or impede the flow of bile out of the lobule and from the liver-producing icterus
What are 2 types of Feline Cholangiohepatitis “syndromes”?
- Lymphocytic cholangitis
- 2nd most common cause of icterus in cats
- lymphocytes and plasma cells centered on portal triads/bile ducts and biliary hyperplasia and fibrosis
- Suppurative/neutrophilic cholangitis
- less common
- thought to be ascending bacteria
This image is of an inflammed portal triad that is infiltrated with lymphocytes. What disease is this in cats? What type of cholestasis is this?
Feline Lymphocytic Cholangitis
Intrahepatic cholestasis