Diseases of the Liver Flashcards
Where does the majority of the liver’s blood supply come from?
80% of it’s blood comes from the portal vein and 20% comes from the hepatic artery.
What are our indicators of liver damage?
Enzymes and bilirubin
What are our indicators of liver function?
Bile acids, ammonia, urea (BUN), glucose, albumin, coagulation factors
How do we classify acute liver injury based on ALT?
1-3 x reference= mild
3-5 x reference= moderate
5 + x reference= severe
Where does ALT live within a hepatocyte?
cytosol
Where does AST live within a hepatocyte?
mitochondria and cytosol
If we saw 3-5 x increase in both ALT and AST on blood work, what should we be thinking?
severe liver injury, probably due to necrosis
If we saw a 5 x increase in AST and only a 2 x increase in ALT on blood work, what should we be thinking?
muscle injury due to the fact AST comes mostly from muscle
What is the half life of ALT?
56 hours
What is the half life of AST?
12 hours
Increases in ALKP and GGT indicate what?
Cholestasis
What is the half life of ALKP?
77 hrs in the dog, 6 hrs in the cat (ALKP is highly specific for liver disease in the cat for this reason)
What is the half life of GGT?
80 hrs in the dog
What else can cause increases in ALKP?
Intestines, kidneys, placenta, bones (increases seen in young growing dogs, but neoplasia can cause this too), drugs (corticosteroids, phenobarbitol), endocrinopathies (Cushing’s, Diabetes, Hypothyroidism, etc)
Where does bilirubin come from?
Liberated from RBCs and transported to the liver. Stored in the gallbladder. Conjugated and excreted via the bile ducts.
Bilirubin is broken down to what in the intestines?
Urobilinogen
If an animal is jaundiced, what can you safely assume?
Confirms liver disease, you do not have to run a bile acids test.
What are the 3 types of jaundice?
- Pre-hepatic (hemolysis like from IMHA)
- Hepatic (liver disorder resulting in intrahepatic bile duct occlusion)
- Post-hepatic (obstruction of common bile duct and gallbladder, ex: pancreatitis and EHBO [extra hepatic biliary obstruction])
How could you rule in whether the jaundice is pre-hepatic?
Decreased PCV or RBCs
How could you rule in whether the jaundice was post-hepatic?
Ultrasound to look for an obstruction
Pancreatic assessment ( snap cPL)
Increased cholesterol
Potential surgical emergency
How could you rule in whether the jaundice was hepatic?
You’d need to rule out pre and post hepatic and consider a liver biopsy. Look at your indicators of liver function: is there hypoalbuminemia?, hypoglycemia?, prolonged PT/PTT?, low BUN? If so we can suspect liver failure.
What is the Bile Acid Stimulation Test good for?
Most specific marker of liver function.
What is the bile acid stim test not good for?
Hepatic and Post-hepatic jaundice
How would you perform a bile acid stimulation test?
- Pull a pre-prandial sample
- Feed a high fat meal like Hill’s A/D
- Pull a post-prandial sample 2 hours later
What are the normal results for a bile acid stimulation test?
Normal Pre <10 umol/L
Normal Post <20 umol/L
When would you see a severe increase in the post-prandial sample?
Acquired or congenital PSS (shunts) (>100 umol/L) 97% sensitive, diffuse parenchymal hepatic disease (failure or cirrhosis) 76% sensitive, biliary stasis, (*MILD increases seen with Cushing’s, Diabetes, and other diseases).
What is a resting ammonia level good to check for?
Hepatic encephalopathy, very sensitive for hepatic parenchymal diseases, can detect chronic hepatitis with more confidence.
Where is ammonia generated?
GI tract
If you have excess ammonia in your blood what could it mean?
Failure of the liver to detoxify into urea or you could have a PSS.
You can get hypoalbuminemia with
33
In dogs, why can you get hypoglycemia related to liver issues?
- PSS
- Fulminant failure
- Young/Toy breeds
What types of crystals would you see in urine with a PSS?
Urate crystals
If you had prolonged clotting times in a patient you knew had liver disease, what could you do for the animal?
Plasma or Vitamin K
~Even if clotting times normal, some people still give Vitamin K (Can give it the day before a liver biopsy)
How would you FNA the liver?
23g 1 inch needle using US guidance with light sedation.
When an animal has ascites it is important that you qualify what that means. What are the 4 different major types of fluid?
- Transudate
~Protein <2.5 g/dL, Cell count <1000 cells/mL
~May see mesothelial cells
~Causes: Hypoalbuminemia PLN, PLE, Liver failure/portal hypertension - Modified transudate
~Protein 2.5-7.5 g/dL, Cell Count 1K-5K cells/mL
~Causes: Right sided congestive heart failure, neoplasia, liver disease - Non-septic exudate
~Protein >3 g/dL, Cell count >5000 cells/mL
~neutrophils with no bacteria
~FIP - Septic exudate
~Protein >3 g/dL, Cell count >5000 cells/mL
~Neutrophils with intracellular bacteria
~GI perforation
What is the time duration of acute liver disease?
<2 weeks
What are the 3 subdivisions of acute liver disease?
- Single cell necrosis
- Acute hepatic failure
- Fulminant hepatic failure
What is single cell necrosis?
Isolate cells are damaged, usually subclinically or clinically silent, enzyme increases present on routine analysis.
What is acute hepatic failure?
Widespread necrosis, could be subclinical.
What are the clinical signs of acute hepatic failure?
Mental dullness, vomiting, PU/PD (this can be from decreased BUN in the interstitial space, Central Diabetes Insipidus, Psychogenic polydipsia), possible icterus, anorexia.
What will our lab work look like with acute hepatic failure?
Increases in ALT, ALP and bilirubin might be increased, liver function might be maintained (ie: bile acids, ammonia may be normal, etc)
What is fulminant hepatic failure?
Massive necrosis, animal will be clinical.
What are the clinical signs of fulminant hepatic failure?
Anorexia, vomiting, diarrhea, mental dullness, hepatic encephalopathy, seizures, bleeding disorders, icterus, hepatomegaly (on x-rays or US).
What will our lab work look like with fulminant hepatic failure?
ALT markedly increased, ALP increase follows, Bilirubin increased, liver function tests fail
If you measured an ammonia level and it showed ammonia levels of 50 mmol/L you have a diagnosis of hepatic encephalopathy. What would you use to treat?
Lactulose up the rear end.
Should also give patients FFP (fresh frozen plasma) because they likely will have a coagulopathy as well.
What would a liver look like on US with diffuse disease?
Diffuse hypoechogenecity and hepatomegaly
What is our standard treatment for acute liver disease?
- Treat/remove underlying cause (decontamination) if there is one.
- Fluid therapy (try to avoid any alkalinizing fluids like Ringer’s Lactate or LRS as they may make the situation worse.)
- Glucose (Dextrose) and K+ CRI if needed
- FFP/Blood
- Vitamin K1
- Antiemetics (If using Cerenia/Maropitant, 1/2 the dose due to the fact it is metabolized by the liver.)
- N-acetyl cysteine (used specifically for Tylenol toxicity, an antioxidant)
- sAME (Denamarin)–an antioxidant
- Phosphatidylcholine–for liver repair
- Silymarin (comes from milk thistle)–an antioxidant
What kind of diet would you feed to an animal with acute liver disease?
Liver diet but not always necessary. (Copper deficient, Na+ deficient, more plant based proteins.) Food and proteins are needed for liver regeneration. With hepatic lipidosis, protein nutrition is the most important.
What are some different etiologies of acute liver disease?
- Toxins (Acetominophen, Carprofen, Diazepam, Aflatoxin [a type of mycotoxin produced by Aspergillus, highly toxic and carcinogenic], Sago palm, Amanita mushroom, Blue-Green Algae, Xylitol)
- Metabolic (Lipidosis)
- Infectious (Infectious canine hepatitis, Ehrilichia, Toxoplasmosis, Babesiosis)
- Hypoxia (Vascular injury)