Icterus and hepatic encephalopathy in small animals Flashcards
icterus - define
hyperbilirubinaemia
bilirubin in the liver
conjugated with glucuronic acid - water soluble for excretion in the urine
pre-hepatic icterus - cause
Haemolysis
Conjugation + uptake of bilirubin into liver overwhelmed
hepatic icterus - cause
Uptake, conjugation and excretion of bilirubin in hepatocytes overwhelmed
post-hepatic icterus - cause
Cholestasis
Conjugation, excretion and uptake back into liver overwhelmed
clinical signs linked with gastrointestinal tract
Vomiting Diarrhoea Acholic faeces Melaena Abdominal effusion = ascites (cirrhosis)
clinical signs linked with neurological system
Personality change Ptyalism (cats) (hypersalivation) Head pressing Disorientation Seizures stupor
clinical signs linked with renal/urinary system
PU/PD
Pollakiuria, stranguria, dysuria
Bilirubinuria
haematological signs
Pale mucous membranes - Anaemia from GI haemorrhage, anaemia of chronic disease, coagulation disorder, haemolysis
DDx for pre-hepatic
Immune Haemolytic Anaemia
Babesia infection
Toxins: Onions, lead, copper
DDx for hepatic - cat
Suppurative Cholangiohepatitis Lymphocytic plasmacytic hepatitis Hepatic Lipidosis Feline Infectious Peritonitis Toxins (acetaminophen, aspirin) Neoplasia
DDx for hepatic - dog
Acute liver disease (toxins)
Leptospirosis
Chronic hepatitis
Neoplasia
DDx for post-hepatic
Pancreatitis
Neoplasia (Liver, duodenum, pancreas)
Cholelithiasis
How would you differentiate between prehepatic and hepatic icterus?
Perform PCV/TS
If prehepatic: PCV low, TS normal
If hepatic: usually PCV normal, TS can be low if Albumin low
How would you differentiate between hepatic and posthepatic icterus?
Ultrasound will identify obstruction of the gall bladder and masses or pancreatitis associated with it
full hepatic disease workup
Haematology, chemistry profile, UA Abdominal ultrasound Liver function tests Coagulation tests Aspirate effusion, cytology Liver fine needle aspirate Fine needle aspirate and culture of bile Liver biopsy: Histology, culture
liver enzymes
ALT: most liver specific enzyme
AST: also present in muscle, intestines…
AP: Biliary duct cells, Isoenzymes: Cortisol-induced (only dogs!), bone, intestines, liver, placenta etc
indications for liver failure on chemistry profile
Low albumin
Low cholesterol
Low glucose
Low BUN (blood urea nitrogen)
measuring bile acid level
first measurement fasted
feed then take second measurement:
rate limiting step = re-uptake of bile acids from the blood into hepatocytes
elevated in liver failure/portosystemic shunt
hepatic encephalopathy
Digestion of proteins: NH3 und aromatic AA go directly into the blood without passing through the liver first
Exposure of CNS to shunted gut-derived toxins
hepatic encephalopathy - clinical signs
Neurologic signs bizarre behaviour head pressing Seizures intermittent blindness Cats: Ptyalism urate stone formation
Most important diseases causing HE in small animals - cats
Acute liver failure (toxic)
Hepatic lipidosis
Neoplasia
Portosystemic shunts
Most important diseases causing HE in small animals - dogs
Portosystemic shunts Liver failure (acute): Toxic, infectious Liver failure (chronic): cirrhosis
