Lecture 11 2/10/25 Flashcards
What are the early, non-specific signs of liver disease?
-hyporexia
-vomiting
-lethargy
-weight loss
-diarrhea
-PU/PD
What are the late stage, more specific signs of liver disease?
-icterus
-hepatic encephalopathy
-hypoglycemia
-ascites
-bleeding tendencies
How does the development time of liver disease impact the clinical signs seen?
-chronic/slowly developing dz gives the liver time to adapt, which can reduce clinical sign severity
-acute/acute on chronic damage leaves no time for adaptation and can result in more severe clinical signs
What are the clinical signs of acute hepatopathy in dogs and cats?
-anorexia
-hepatic encephalopathy
-vomiting
-polydipsia
-dehydration
-jaundice
-fever
-cranial abdominal pain
-coagulopathy/petechiae/melena/hematemesis
-ascites
-splenomegaly
-acute kidney injury
What are the clinical signs of chronic hepatopathy in dogs and cats?
-vomiting and/or diarrhea
-hematemesis/melena
-inappetence
-weight loss
-PU/PD
-ascites
-jaundice
-hepatic encephalopathy
-bleeding tendencies
What is icterus?
yellow discoloration of tissues and body fluids secondary to hyperbilirubinemia and bile pigment deposition
Where are the most sensitive places to identify icterus?
-sclera
-conjunctiva
-soft palate
-below the tongue
What are the clin path findings in a patient with prehepatic/hemolytic icterus?
-moderate or marked decrease in hematocrit
-possible spherocytes
-possible auto-agglutination
-possible positive Coombs test
-possible hemoglobinemia and/or hemoglobinuria
What are the clin path findings in a patient with hepatic icterus?
-normal hematocrit or mildly decreased hematocrit
-high increases in ALT and AST
-increases in ALP and GGT
-decreases in albumin, cholesterol, glucose, and urea
What are the clin path findings in a patient with posthepatic icterus?
-normal hematocrit or mildly decreased hematocrit
-increases in ALT, AST, and cholesterol
-high increases in ALP and GGT
-WNL albumin, glucose, and urea
What is ascites?
accumulation of free fluid within the abdominal cavity
How is ascites detected?
-abdominal distention (severe)
-positive ballottement (severe)
-radiography
-abdominal ultrasound
What are the causes of ascites that are related to the hepatobiliary system?
-portal hypertension
-hypoalbuminemia
-gallbladder rupture
What causes portal hypertension?
increased resistance and/or blood flow in portal circulation
What is hepatic encephalopathy?
neurologic dysfunction in patients with liver dz
What is the general etiology of hepatic encephalopathy?
dysmetabolism of toxins due to liver dysfunction and/or portsystemic bypass
What are the most common causes of hepatic encephalopathy in dogs?
-congenital portosystemic shunts
-acquired portosystemic shunts due to portal hypertension
-acute liver failure without shunting
What are the most common causes of hepatic encephalopathy in cats?
-congenital portosystemic shunts
-arginine deficiency secondary to hepatic lipidosis
-acute liver failure without shunting
What is the pathogenesis of portosystemic shunt/liver dysfunction?
ammonia-rich blood from portal circulation “bypasses” the liver and flows directly into systemic circulation
What percent of dogs and cats with congenital portosystemic shunt develop hepatic encephalopathy?
around 70%
Which brain neurotoxins/neuroinhibitors are implicated in hepatic encephalopathy pathogenesis?
-ammonia***
-glutamine
-gamma-aminobutyric acid
-benzos/benzo-like substances
-tryptophan/serotonin
-aromatic amino acids
-manganese
-opioids
What are the early clinical signs of hepatic encephalopathy?
-mild confusion
-inappetance
-dullness
-irritability
What are the advanced clinical signs of hepatic encephalopathy?
-ataxia
-circling
-head pressing
-salivation
-seizures
-stupor
-coma
How is hepatic encephalopathy diagnosed?
-evidence of liver dysfunction in patient with neurological signs
-exclusion of other known brain diseases
-episodic signs of encephalopathy that may worsen after eating
-hyperammonemia
What are precipitating factors for hepatic encephalopathy?
-GI hemorrhage
-excessive protein intake
-infection
-medications
-hyponatremia
-hypokalemia
-metabolic alkalosis
-renal failure
-dehydration
-constipation
-overzealous diuretic use
-diarrhea
What are the screening tests that should be done in patients with suspected hepatopathy?
-CBC
-serum chem
-UA
-fecal
-abdominal radiographs
-abdominal ultrasound
What should be done if the screening tests indicate hepatopathy?
-rule out secondary hepatopathy
-confirm with more specific tests such as tissue sampling
What are the common causes of secondary hepatopathy?
-right sided CHF
-hypoxia
-glucocorticoids
-diabetes mellitus
-hyperlipidemia
-hyperthyroidism
-hypothyroidism
-non-hepatic inflammatory dz
-drug-induced
-metastatic neoplasia
What interpretations may be made regarding hepatopathy once history, PE, screening tests, and specific tests are completed?
-primary vs secondary disorder
-pattern of disease
-estimate of degree of hepatobiliary dysfunction
What is the most important test for determining the type and severity of hepatobiliary dz?
liver biopsy
Which hepatobiliary conditions DO NOT require a liver biopsy for definitive diagnosis?
-gall bladder mucocele
-congenital vascular anomalies
-biliary tract infections
Which biochemical tests help to determine primary vs secondary hepatobiliary dz?
-hepatocellular liver enzymes; ALT and AST
-hepatobiliary/cholestatic liver enzymes; ALP and GGT
-bilirubin
Which nonspecific biochemical tests can provide indications of liver function?
-total protein and albumin
-coagulation tests
-urea
-glucose
-cholesterol (if no evidence of cholestasis)
Which biochemical tests can provide more specific indications of liver function and or/portosystemic shunting?
-pre- and post-meal bile acids testing (if no evidence of cholestasis)
-ammonia
Which biochemical tests can provide more specific indications of liver function only?
bilirubin (if no evidence of cholestasis)
Which liver diseases can present with normal liver enzymes?
-portosystemic shunt
-microvascular dysplasia
-metastatic hepatic neoplasia
-end-stage cirrhosis
Which diseases will often present with increased liver enzymes and normal functional indices?
secondary hepatopathies
What are the general characteristics of liver enzymes?
-degree of increase is related to degree of damage, not liver function
-degree of enzyme increase is NOT prognostic
-increase is more common in primary liver dz
-reactive hepatopathy can occur when organs with portal venous drainage are damaged
What are the characteristics of ALT?
-more sensitive for liver injury than AST; higher increase
-most specific to liver injury
What are the characteristics of AST?
-less sensitive than ALT
-less specific than ALT due to presence in liver, muscle, and RBCs
-increased AST w/ normal ALT indicates extrahepatic source
-AST > ALT with elevated CK indicates muscle origin; normal CK indicates RBC origin
What are the characteristics of ALP?
most common change on biochem panel in dogs
-lowest specificity for hepatobiliary dz in dogs
-increases with cholestatic dz, hepatocellular carcinoma, steroids, and feline hepatic lipidosis
What are the characteristics of GGT?
-production stimulated by steroids in dogs
-increases in feline cholangitis
What is delta bilirubin?
conjugated bilirubin in plasma bound irreversibly to albumin via covalent bonds
What are the characteristics of bile acids?
-increase in portosystemic shunt, parenchymal hepatic dz, and cholestasis
-sensitive and specific for hepatobiliary dz and/or portosystemic shunt IF there is no cholestasis
-severity of increase does not relate to disease category
What are the characteristics of hyperammonemia?
-portosystemic shunt and acute hepatocellular inability to detoxify ammonia into urea can lead to hepatic encephalopathy
-must see >70% reduction in urea cycle function to see hyperammonemia
-arginine is essential AA for urea cycle in cats; anorexia can reduce urea cycle
What are the characteristics of coagulation proteins and hepatopathy?
-abnormal coagulation is common but spontaneous bleeding is rare
-marked coagulopathy correlates with functional failure as a prognostic value
-PT increase is the most common coagulopathy in cats
What are the characteristics of protein C?
-anticoagulant protein synthesized in the liver
-biomarker of hepatoportal perfusion
-can be used to distinguish between macroscopic shunting and microvascular dysplasia
How is protein C activity level interpreted in the face of abnormal bile acids and no evidence of severe liver injury or cholestasis?
-protein C activity level <70% is consistent with PSS
-protein C activity level >100% is consistent with microvascular dysplasia
What can be identified on abdominal radiography with regards to the liver?
-liver size
-normal gastric axis
-hepatomegaly
-microhepatica
-ascites
-free gas in region of liver
What are the characteristics of abdominal ultrasound for liver evaluation?
-low sensitivity; liver can appear unremarkable despite severe dz
-normal appearance does not rule out hepatic dz
-allows for visualization of internal structure/echogenicity and lesions within parenchyma
Which conditions is abdominal ultrasound most useful for assessment?
-extrahepatic bile duct obstruction
-cholecystitis
-choleliths
-gallbladder mucocele**
-ascites**
-portal hypertension**
-PSS
What are the characteristics of CT evaluation of the liver?
-used to evaluate liver size, hepatic mass lesions, and PSS
-CT angiography has good sensitivity and specificity for CPSS
-less operator-dependent than ultrasound
What are the characteristics of trans-splenic portal scintigraphy?
-used when evaluating CPSS
-used to determine shunt termination
-provides quantitative analysis of shunt fraction
What are the pros of liver FNA compared to biopsy?
-less invasive
-fewer risks
-faster results
-less expensive
What are the cons of liver FNA compared to biopsy?
-low cellularity
-chance for artifacts
-no assessment of tissue architecture
What is the overall agreement between liver FNA and histology?
between 30 and 61%
Which diseases can liver FNA help detect?
-vacuolar hepatopathy
-hepatic lipidosis
-round-cell neoplasia
-infection
What are the most common techniques for hepatic biopsy?
-core needle biopsy
-laparoscopic biopsy
-surgical biopsy
