Unit 3 - Hepatic Flashcards
Where is the liver located in the horse?
It is located to the right of midline, entirely within the rib cage
True or False: Horses do not have a gall bladder.
True
Where does the common bile duct open into?
The proximal duodenum
What does the equine liver synthesize?
Proteins, coagulation factors. and glucose
What does the equine liver deaminate?
amino acids for energy and ammonia into urea
What does the equine liver do to fatty acids?
Uptake, esterification, and oxidization
What does the equine liver metabolize?
toxins
What clinical signs are associated with hepatic disease in the horse?
Weight loss, decreased appetite, fever, icterus, colic signs, edema, ascites, photosensitization, and abnormal behavior/mentation
What liver leakage enzymes will be elevated in cases of hepatic disease in the horse?
SDH, LDH, and AST
What membrane bound enzymes will be elevated on serum chemistry in a horse with hepatic disease?
GGT and ALP
What are some non-specific markers of hepatic disease on serum chemistry in the horse?
Albumin, BUN, glucose, and bilirubin
At what level do leakage enzymes become a significant concern?
At least 2-3x within the reference range
What is the most liver specific leakage enzyme in horses?
SDH
What do elevations in SDH indicate?
That there is active or ongoing liver damage because the half life is short
What is AST a leakage enzyme for?
The liver and skeletal and cardiac muscle
Why is AST less sensitive than SDH?
Because its half-life is 2-10 days - it is slow to rise and slow to fall
What is LDH a leakage enzyme for?
The liver and skeletal muscle
What non-hepatic disease process will elevate LDH?
hemolysis
Where are hepatic membrane bound enzymes found?
in the biliary tract
What are hepatic membrane bound enzymes a marker for?
hepatobiliary disorders and cholestasis
When do membrane bound enzymes become concerning?
When they are elevated at 2-3x their reference range
What enzyme is the best indicator for biliary disease in the horse?
GGT
Typically, when is albumin decreased in relation to hepatic disease?
In end-stage liver disease
What is BUN produced by?
The liver when processing/detoxifying ammonia
When is glucose decreased in relation to hepatic disease?
In end-stage liver disease
What is the most common reason for elevated unconjugated bilirubin?
Anorexia
What causes elevated unconjugated bilirubin?
Decreased hepatic uptake or decreased conjugation of bilirubin
What causes conjugated bilirubin elevations?
Intrahepatic cholestasis or extrahepatic bile duct obstruction
What may a CBC show in patients with hepatic disease?
Leukocytosis and hyperfibrinogenemia
What additional diagnostic tools are good for evaluation of hepatic disease in horses?
Transcutaneous abdominal ultrasound, percutaneous liver biopsy, bile acids, and ammonia
Where is the liver best visualized during a transcutaneous abdominal ultrasound?
On the right side of the horse between the lungs/diaphragm and large colon
What does a normal liver look like on transcutaneous abdominal ultrasound?
Homogenous echogenicity, crisp edges, subjective size, few bile ducts with hypoechoic contents, unable to see the portal vein, and no shadowing effects
What does an abnormal liver look like on transcutaneous abdominal ultrasound?
Heterogenous echogenicity, subjective size, many dilated bile ducts with hyperechoic sludge contents or shadowing, able to identify the portal vein, and shadowing effects
If the liver is readily findable on the left, everywhere on the right, and with round edges, what does that indicate?
It is swollen and enlarged