Gastro - Hepatic Encephalopathy Flashcards
What can cause chronic hepatitis?
Mostly idopathic, copper accumulation, drugs, infections, and familial predisposition
What breeds are predisposed to chronic hepatitis?
Dobermann, Bedlington Terrier, Cocker Spaniel, Dalmation, Sky Terrier, Poodle, Labrador Retriever, GSD, Scottish terrier, Beagle
What laboratory values are associated with chronic hepatitis?
Elevated ALT and AP
Decreased Albumin and Urea
Elevated bile acids and ammonium levels
Note: If cirrhosis is already present there will be no liver enzyme elevation
What will you see on a liver biopsy as evidence of chronic hepatitis?
Lymphoplasmacellular inflammation and necrosis of the hepatocytes which lie adjacent to the portal tracts
How is chronic hepatitis treated?
Glucocorticoids (1-2 mg/kg/day) until clinical amelioration is seen then taper down
UDCA (15 mg/kg PO SID)
Antioxidants
Copper-chelation if Cu is >2000 ppm
What causes hepatic encephalopathy?
NH3 and aromatic AA go into the blood without going into the liver like they are supposed to creating a toxic effect
What clinical signs are associated with encephalopathy?
Neurological signs: bizarre behavior, head pressing, seizures, intermittent blindness, and ptyalism in cats
Urate stone formation: dysuria, stranguria, and hematuria
How do urate stones form as a result of hepatic encephalopathy?
There is an increased ammonium concentration in blood due to the decreased ability to convert uric acid to allantoin in the liver and thus more urate is excreted in the urine
What are the ‘most important’ causes of hepatic encephalopathy in cats?
acute liver failure (toxic), hepatic lipidosis (most important/common), neoplasia, and portosystemic shunts
What are the ‘most important’ causes of hepatic encephalopathy in dogs?
Portosystemic shunts (most important), liver failure (acute and chronic)
Describe how hepatic lipidosis happens.
A cat undergoes starvation which results in a release of Free Fatty Acids and Triglycerides into the liver. Normally that is fine, but the liver needs protein to transport the fats out. Since the cat isn’t eating, it has no protein (carnithin-deficiency) and the lipids build up. There is also an arginine-deficiency which leads to decreased production of apolipoproteins leading to a decreased release of very low density lipoproteins.
Ultimately all of these things lead to a huge buildup of lipid in the liver
What is lactulose metabolized by?
colonic bacteria
What happens when colonic bacteria metabolize lactulose?
They produce acids which reduce the pH in the colon
Why is a reduced pH in the colon a good thing?
The ammonium produced by the bacteria becomes NH4 (the ionized form), and it can no longer become absorbed in the blood and gets lost in the feces
Aside from interacting with the colonic bacteria, what else does lactulose do?
It causes water to be drawn into the colonic lumen which leads to diarrhea and wash out of the feces and bacteria
