Icterus in Small Animals Flashcards
What is icterus?
hyperbilirubinaemia
What are the different types of icterus and their causes?
Pre-hepatic - Haemolysis, conjugation and uptake overwhelmed
Hepatic - uptake, conjugation and excretion overwhelmed
Post-hepatic - Cholestasis, conjugation, excretion and uptake back to liver overwhelmed
What are some of the signs of HE?
Changes in personality Ptyalism (cats) Head pressing Seizures Disorientation Stupor
What are the DDx for prehepatic icterus?
HAEMOLYSIS
-Immune Haemolytic Anaemia
Babesia Infection
Toxins
What are the DDx for hepatic icterus in the cat?
- Suppurative cholangiohepatits
- Lymphacytic plasmacytic hepatitis
- Hepatic lipidosis
- FIP
- Toxins
- Neoplasia
What are the DDx for hepatic icterus in the dog?
- Acute liver disease (toxins)
- Leptospirosis
- Chronic Hepatitis
- Neoplasia
What are the DDx for posthepatic icterus?
- Pancreatitis
- Neoplasia
- Cholelithiasis (uncommon)
How would you differentiate between prehepatic and hepatic icterus?
PCV + TP
Pre-hepatic - low PCV but TP normal
Hepatic - normal PCV (TP may be low if albumin is affected)
When would imaging be used when diagnosing the cause of icterus?
To determine whether hepatic and post hepatic - this will allow visualisation of the gall bladder and pacreas.
What is the workup for hepatic diseases?
Haem, biochem, UA Liver Function test Coagulation test Ultrasound FNA (and culture of bile) Liver biopsy
Why is it important to do a coagulation test when working up the liver?
Need to do prior to biopsy as biopsy may result in severe bleeding.
Why is liver enzyme elevation not always indicative of liver function?
Can happen due to reversible damage to hepatocytes. Liver has a huge regenerative capacity
Which liver enzymes are present where?
ALT specific to liver
AST in muscle and intestines
AP biliary duct cells. Can be cortisol induced production
What indicators, other than liver enzymes, are there of liver failure on a biochem profile?
Low albumin, cholesterol, glucose and BUN
How is a bile acid test performed in SAs, and what does it indicate?
Measure fasted then after a meal - as bile is released in response to meal.
If bile acids are present in the blood this indicates reduced uptake into the liver from the portal vein.
