Canine and Feline Liver Disease Flashcards
what are the causes of acute hepatitis?
- hepatotoxins (CCl4, mycotoxins, xylitol)
- drugs (acetaminophen in cats, azathioprine, trimethoprim-sulfa)
- mushrooms (Amanita)
- viruses
- sago palm (when ingested, esp in FL)
- cause usually can’t be found so get histo diagnosis of just toxic hepatitis
how is acute hepatitis diagnosed?
- increase in ALT and AST
- ALP normal or mildly increased
- increase in serum bilirubin if many hepatocytes affected
- liver biopsy not helpful or essential
how is acute hepatitis managed?
- good prognosis if cause found, stop any suspected drugs
- supportive care w/ fluids
- anti-emetics
- nutritional support
- antioxidants maybe, especially if amanita mushroom toxicity
what are the possible causes of chronic hepatitis in the dog?
leptospirosis
drugs (phenobarbital)
copper metabolism
idiopathic
which breeds are prone to chronic hepatitis?
Dobermans, Cocker Spaniels, Labrador Retrievers
which breeds are susceptible to copper-associated hepatopathy?
Dalmation, Bedlington terrier, West Highland white terrier, Labradors
how is chronic hepatitis managed?
- remove the cause (drugs, copper)
- anti-inflammatories (GCs usually)
- antioxidants
- supportive therapy
- copper chelators for copper related disease, copper restricted diet
- UCDA (bile acid to prevent apoptosis and mitochondrial damage, increase bile flow, immunodilating effects)
what are the two forms of cholangitis in the cat?
neutrophilic and lymphocytic
based on type of infiltrate in the bile duct lumen and/or biliary epithelium, need a liver biopsy and bile culture to diagnose
what are the signs of neutrophilic cholangitis?
- fever, lethargy, vomiting, jaundice
- may be acute or chronic
- thought to be from ascending bacterial infection from intestine
what are the signs of lymphocytic cholangitis?
- ascites and jaundice
- may be from some initiating factors that triggers immune-mediated mechanisms that perpetuate liver pathology
what is triaditis?
cholangitis + pancreatitis + inflammatory bowel disease
what is the treatment for neutrophilic cholangitis?
- antibiotic therapy (based on culture), E. coli usually the culprit
- glucocorticoids for inflammation
- cholecystectomy: in cases with inspissated bile and biliary duct obstruction
- fluid therapy and nutritional support
what is the treatment for lymphocytic cholangitis (and chronic neutrophilic/mixed inflammatory)?
- glucocorticoids at immunosuppressive doses
- may treat with antibiotics if suspect chronic neutrophilic cholangitis
- fluids, nutritional, antioxidant support
- with ascites, give low Na+ diet and diuretics
what is the most common liver disease of the cat?
hepatic lipidosis
what are the causes of feline hepatic lipidosis?
- may be primary idiopathic or secondary
- no confirmed etiology
- from formation of a metabolic disorder
- believed to be related to pathogenesis of malnutrition
- obesity = increased risk
- increased risk from sudden rapid weight loss or decreased calorie intake
- may be related to negative nitrogen balance
what are the lab findings with feline hepatic lipidosis?
- dramatic increase in ALP (short half life so only see with disease)
- increase in ALT (higher than ALP, may have lipidosis and another liver disease)
- moderate increase in AST
- normal or mildly increased GGT
- normocytic, normochromic, non-regenerative anemia
what are some additional ways to diagnose feline hepatic lipidosis?
- history of anorexia, fat cat with muscle wasting, or increased ALP with normal GGT
- hepatomegaly in x-ray with rounded margins
- hyperechogenic ultrasound of liver
- may make diagnosis off tissue aspiration, careful not to misinterpret normal fat vacuoles
how is feline hepatic lipidosis managed?
- nutritional support (60 kcal/kg/day at least)
- treat any concurrent illness/underlying cause
- usually place an E-tube
- metoclopramide or cisapride for delayed gastric emptying
- antiemetics if vomiting
extrahepatic biliary obstruction
impairment of bile flow in biliary system between liver and duodenum
what are the clinical signs of extrahepatic biliary obstruction?
very general, vomiting, lethargy, inappetance
how is extrahepatic biliary obstruction diagnosed?
marked increase in ALP (always higher than ALT), can only confirm by laparotomy
what are the causes of extrahepatic biliary obstruction?
pancreatitis in the dog
pancreatic and biliary neoplasia in the cat
how is extrahepatic biliary obstruction managed?
medically, non-resolving may need surgical correction
what is a congenital portosystemic shunt?
abnormal development of hepatic portal circulation
what are the pre-dispositions for congenital portosystemic shunts?
young dogs that are “small” for their age and “don’t do well”
yorkies, miniature Schnauzers, and Maltese predisposed
Irish wolfhound increased frequency
intrahepatic shunts are more common in which animals?
large breed dogs
extrahepatic shunts are more common in which animals?
cats and small breed dogs
what is the clinical presentation of portosystemic shunt and hepatic encephalopathy in cats?
small stature, ptyalism, copper irises
may see PU/PD and urate stones
what are the lab findings with portosystemic shunt and hepatic encephalopathy?
- biochemical profile may be normal
- ALT, AST, ALP, and GGT may be normal or mildly increased
- ammonium biurate crystals in urine
- low urea nitrogen, albumin, and glucose, microcytic anemia from low iron (decreased synthesis)
- one or more liver function tests abnormal (bile acids, ammonia)
what are the diagnostic imaging techniques used to diagnose portosystemic shunt and hepatic encephalopathy?
- ultrasound: may see small aortic to portal vein ratio, renomegaly, may visualize shunt
- CT angiogram
- transplenic scintigraphy: not used anymore
How are portosystemic shunt and hepatic encephalopathy managed?
- controversy over best tx
- medical: restricted protein, high quality diet and lactulose, antibiotics (acute), stabilize medically before surgery
- surgical ligation of shunt (through jug to CVC and block vessel, cellophane banding, ameroid constrictor)
how does hepatology in cats differ from dogs?
- common bile duct and pancreatic duct join before entering duodenal papilla
- glucouronyltransferase deficiency (excrete NSAIDs and secrete bilirubin slower)
- gluconeogenesis never shuts down when fasting
- can’t synthesize arginine (encephalopathy with arg deficient diet)
- need taurine to conjugate bile acids
- AST increase less dramatic, associated with muscular dystrophy
- ALP in response to epithelial stimulus, suggest hepatic disease
- jaundice earlier than dogs b/c of reduced glutathione concentrations and decreased secretory ability
- high renal threshold for bilirubin
- bile acids sensitive for liver function
- rare hypoalbuminemia in cats with liver disease
- hyperglobulinemia can be concurrent with liver disease
what is vacuolar hepatopathy?
glycogen accumulation in liver vacuoles due to steroids (endogenous or exogenous)
what are the clinical signs of vacuolar hepatopathy?
PU/PD, polyphagia, panting, swollen abdomen, ALP increase with normal bilirubin (diagnosed by liver aspirate/biopsy)
