Icterus and liver / pancreas disease Flashcards
pancreas enzyme specificity?
amylase and lipase arent very specific
can use CPLI (canine pancreatic lipase) which is specific
What hepatocellular enzymes are used to measure damage to hepatocytes?
ALT - most specific in cats and dogs, can be released from massively damaged muscle
AST - also in muscle and RBC
SDH - used in horse
GLDH
What can you measure to rule out muscle involvement?
Creatinine kinase - increases and decreases faster than ALT and AST
What enzymes are used to measure cholestasis?
ALP - from bile duct ep and increases with cholestasis, there is a steroid induced isoform in dogs, very short half life in cats
GGT - from bile duct ep, used in large animals
How would you expect the measure of hepatic function to change with liver failure?
high bilirubin low urea high ammonia low glucose low albumin altered cholesterol
What are the 6 main things measured to test hepatic function?
bilirubin - check conjugated vs unconjugated
ammonia and urea glucose cholesterol - increase with cholestasis and decrease with hepatic failure bile acids (no gall bladder in horses) ammonium - hard to measure
How is icterus categorised?
pre-hepatic, hepatic and post hepatic
What is pre-hepatic icterus?
increased bilirubin production - haemolysis
mainly unconjugated bilirubin
What are the main causes of pre-hepatic icterus in horses?
neonatal isoerythrolysis, EIA, autoimmune haemolytic anaemia
What is hepatic icterus?
impaired hepatic uptake or conjugation of bilirubin
increased unconjugated than normal
Main causes of hepatic icterus in horses?
(hepatocellular disease,) anorexia
What is post-hepatic icterus?
impaired excretion of bilirubin
more conjugated
Main causes of post - hepatic icterus in horses?
cholangitis, cholangiohepatitis
Main ddx for horse icterus?
1) anorexia
2) anaemia
3) liver disease
Horse clinical signs of liver disease?
-common: depression anorexia colic (mild) weight loss icterus
-uncommon:
photosensitization, diarrhoea, bilateral laryngeal paralysis, haemorrhagic diathesis, ascites, dependent oedema
What is hepatic encephalopathy?
severe hepatic dysfunction causing clinical signs of cerebral disease
can be due to reduced ammonia clearance so toxic ammonia gets to brain
cat causes: acute liver failurs, hepatic lipidosis, neoplasia
dog causes: portosystemic shunt, liver failure
Main diagnostics for hepatic disease in horses?
bloods:
bile acids
SDH
GGT
ultrasonography
hepatic biopsy
Treatment of hepatic disease in horses?
supportive
HE - sedate and hypertonic saline for cerebral oedema
Dietary - high carb., limited protein
What is pyrrolizidine alkaloid toxicity in horses?
Ragwort poisoning
cumulative over 4 - 12 weeks
PA is normally metabolised by the liver to toxic pyrrole derivatives which are anti-mitotic to see megalocytes on biopsy
poor prognosis
What is Theillers disease in horses?
unknown cause
widespread hepatic necrosis and a small liver
What is Tyzzer’s disease in horses and what is it caused by?
Clostridium piliformis
in 7-42 day old foals
found dead
multifocal hepatitis and enteritis
What can cause and how to diagnose and prognosis of cholelithiasis in horses?
Cause: parasites, ascending biliary inf, biliary stasis
Diagnose: fever + icterus + colic , lliver enzymes, ultrasounds, biopsy and histopath.
Prognosis: depends on degree of fibrosis
What is hyperlipaemia in horses?
- mainly seen in obeses shetlands/ ponies
- due to a negative energy balance recruiting fat stores so triglycerides (TG) are made in the liver and as they are obese there is so much fat broken down that the TG cant be taken up by peripheral tissues so stays in the liver
- measure TG in serum
- treat: reverse NEB, support hepatic disease, eliminate stress, inhibit further fat metabolism (insulin) , try and increase TG uptake by peripheral tissues
- poor prognosis
DDX for pre-hepatic icterus in small animals?
immune mediated haemolytic anaemia, babesia,toxins
DDX for hepatic icterus in cat and dog?
cat - suppurative (neutrophilic) / non suppurative (lymphocytic) cholangiohepatitis, lymphocytic plasmocytic hepatitis, hepatic lipidosis, FIP, toxins, neoplasia
dog - acute liver disease, leptospirosis, chronic hepatitis, neoplasia
DDX for post- hepatic icterus in small animals?
pancreatitis , neoplasia, cholelithiasis, pancreatic disease ( neoplasia, abscess) , bile duct rupture
How do you differentiate between pre / hepatic/ post icterus?
pre vs hepatic : blood (PCV)
hepatic vs post : abd rads / ultrasound - blockages
Cat-, serum albumin as if hypoalbuminaemia then likely hepatic but normal doesn’t help
Small animal clinicalCats signs of icterus?
- GI : vom, dia, acholic faeces, melaena, ascites
- neurologic: personality change, ptyalism (drooling cats) , head pressing, disorientation, seizures, stupor
- Renal / urinary: PU/PD , pollakiuria, stranguria, dysuria, bilirubinuria
- Haematologic : pale MM
How does the bile acid function test work?
test fasted levels then feed
should normally increase then decrease in blood
if remains increased then impaired uptake back into liver
What is hepatic lipidosis in cats?
Cats normally live on a protein only diet so if theyre anorexic then FA are released from adipose tissue and go to the liver. Normally they are b-oxidised and made into energy and low density lipoproteins but when liver isnt working they accumulate
Outline normal bilirubin metabolism
from old RBC , unconjugated but bound to albumin in the blood - liver - conjugated to glucronic acid and unbound from albumin - now water soluble - liver
