Icterus and hepatic encephalopathy in small animals

Question 1

icterus - define

Answer 1

hyperbilirubinaemia

Question 2

bilirubin in the liver

Answer 2

conjugated with glucuronic acid - water soluble for excretion in the urine

Question 3

pre-hepatic icterus - cause

Answer 3

Haemolysis

Conjugation + uptake of bilirubin into liver overwhelmed

Question 4

hepatic icterus - cause

Answer 4

Uptake, conjugation and excretion of bilirubin in hepatocytes overwhelmed

Question 5

post-hepatic icterus - cause

Answer 5

Cholestasis

Conjugation, excretion and uptake back into liver overwhelmed

Question 6

clinical signs linked with gastrointestinal tract

Answer 6

Vomiting
Diarrhoea
Acholic faeces
Melaena
Abdominal effusion = ascites (cirrhosis)

Question 7

clinical signs linked with neurological system

Answer 7

Personality change
Ptyalism (cats) (hypersalivation)
Head pressing
Disorientation
Seizures
stupor

Question 8

clinical signs linked with renal/urinary system

Answer 8

PU/PD
Pollakiuria, stranguria, dysuria
Bilirubinuria

Question 9

haematological signs

Answer 9

Pale mucous membranes - Anaemia from GI haemorrhage, anaemia of chronic disease, coagulation disorder, haemolysis

Question 10

DDx for pre-hepatic

Answer 10

Immune Haemolytic Anaemia
Babesia infection
Toxins: Onions, lead, copper

Question 11

DDx for hepatic - cat

Answer 11

Suppurative Cholangiohepatitis
Lymphocytic plasmacytic hepatitis
Hepatic Lipidosis
Feline Infectious Peritonitis
Toxins (acetaminophen, aspirin)
Neoplasia

Question 12

DDx for hepatic - dog

Answer 12

Acute liver disease (toxins)
Leptospirosis
Chronic hepatitis
Neoplasia

Question 13

DDx for post-hepatic

Answer 13

Pancreatitis
Neoplasia (Liver, duodenum, pancreas)
Cholelithiasis

Question 14

How would you differentiate between prehepatic and hepatic icterus?

Answer 14

Perform PCV/TS
If prehepatic: PCV low, TS normal
If hepatic: usually PCV normal, TS can be low if Albumin low

Question 15

How would you differentiate between hepatic and posthepatic icterus?

Answer 15

Ultrasound will identify obstruction of the gall bladder and masses or pancreatitis associated with it

Question 16

full hepatic disease workup

Answer 16

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

Question 17

liver enzymes

Answer 17

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

Question 18

indications for liver failure on chemistry profile

Answer 18

Low albumin
Low cholesterol
Low glucose
Low BUN (blood urea nitrogen)

Question 19

measuring bile acid level

Answer 19

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

Question 20

hepatic encephalopathy

Answer 20

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

Question 21

hepatic encephalopathy - clinical signs

Answer 21

Neurologic signs
bizarre behaviour
head pressing
Seizures
intermittent blindness
Cats: Ptyalism
urate stone formation

Question 22

Most important diseases causing HE in small animals - cats

Answer 22

Acute liver failure (toxic)
Hepatic lipidosis
Neoplasia
Portosystemic shunts

Question 23

Most important diseases causing HE in small animals - dogs

Answer 23

Portosystemic shunts
Liver failure (acute): Toxic, infectious
Liver failure (chronic): cirrhosis