Gastro - Icterus Flashcards
What are the causes of icterus?
Pre-hepatic, hepatic, and post-hepatic
What causes prehepatic icterus?
Hemolysis - conjugation and uptake of bilirubin into the liver is overwhelmed
What is ‘overwhelmed’ with hepatic icterus?
Uptake, conjugation, and excretion of bilirubin in the hepatocytes is overwhelmed
What is the cause of post-hepatic icterus?
Cholestasis which causes conjugation, excretion, and uptake back into the liver to be overwhelmed
What GI signs can give clues to icterus and liver disease?
Vomiting, diarrhea, acholic feces, melena, and abdominal effusion (ascites)
What neurologic signs can give clues to icterus and liver disease?
Personality change, ptyalism (cats), head pressing, disorientation, seizures, and stupor
What renal/urinary signs can give clues to icterus and liver disease?
PU/PD, pollakiuria, stranguria, dysuria, and bilirubinuria
What could cause pale mucus membranes?
Anemia from GI hemorrhage, anemia of chronic disease, a coagulation disorder, and hemolysis
What are the differentials for prehepatic icterus?
Immune hemolytic anemia, babesia infection, mycoplasma hemofelis, cytoxzoon, and toxins such as onions, lead, and copper
What are the differential diagnoses for hepatic icterus in cats?
Suppurative cholangiohepatitis Lymphocytic plasmacytic hepatitis Hepatic lipidosis Feline Infectious peritonitis Toxins (acetaminophen,aspirin) Neoplasia
What are the differential diagnoses for hepatic icterus in dogs?
Acute liver disease (toxins), leptospirosis, chronic hepatitis, and neoplasia
What are the differential diagnoses for posthepatic icterus?
Pancreatitis, neoplasia, and cholelithiasis
How would you differentiate between prehepatic and hepatic icterus?
Perform a PCV/TS
If prehepatic - PCV is low, TS is normal
If hepatic - PCV is usually normal, TS can be low if albumin is low
How would you differentiate between hepatic and post-hepatic icterus?
Imaging:
Ultrasound will identify obstruction of the gall bladder, and masses, or pancreatitis associated with it
What diagnostic tests can be done for hepatic diseases?
Bloodwork, UA, abdominal ultrasound, liver function tests, coagulation tests, aspirate effusion and cytology, liver fine needle aspirate, fine needle aspirate and culture of bile, and a liver biopsy
What is the most liver specific enzyme?
ALT
What liver enzyme is also present in the muscle, intestines, and other organs?
AST
What produces the enzyme AP?
biliary duct cells
In what species does AP have isoenzymes in? What does this mean?
Dogs
It means that if you give cortisol, the levels of AP will increase, so you need to keep this in mind when looking at chemistry results
What are some indications of liver failure on a chemistry profile?
Low albumin, low cholesterol, low glucose, and low BUN
Where are bile acids produced?
in the liver from cholesterol
After bile acids are produced, where do they go?
Into the enterohepatic circulation and then eventually there is re-uptake from the blood into the hepatocytes
How is a bile acids test done?
You take a measurement, give food, and then take another measurement some hours later
When are bile acids elevated after a bile acid test?
in liver failure/portosystemic shunt
