approach to the yellow patient

Question 1

List the THREE main underlying pathological processes that cause icterus/jaundice. [3 marks]

Answer 1

1. pre hepatic = rapid and excessive breakdown of RBCs releasing bilirubin
2. heptic = liver damage imparis ability to conjugate and excrete bile leading to build up in blood
3. post hepatic = obstruction of bile duct

Question 2

Explain why a severe reduction in liver function can result in a patient presenting with yellow mucous membranes. [6 marks]

Answer 2

• The liver is involved in the management of products from the breakdown of haem[oglobin] from RBCs. [1]
• One of the products of the breakdown of haem[oglobin] is bilirubin. [1]
• Bilirubin is yellow in colour. [1]
• Bilirubin is processed by the liver and excreted in bile. [1]
• f the liver is not functioning it cannot process the bilirubin quickly enough. [1]
  -Therefore bilirubin accumulates in the plasma and tissues. [1]

Question 3

what would be the initial diagnostic test of choice to rule out pre-hepatic causes of icterus

Answer 3

hematology profile

Question 4

what are some common presenting hx and clinical signs of liver disease in horses

Answer 4

• uncommon in clinical disese, seen more in inappetent/anorexic horse
• mild recurrent colic
• jaundice
• lethargy
• photosensitisation
• weight loss (chronic)
• neuro changes (head pressing, circling abnorm behave)
• pyrexia

Question 5

explain aetiology and pathogenesis of liver failure in the horse

Answer 5

• anorexia
• haemolytic disease (neonatal isoerythrolysis)
• hepatobiliary causes (inflammation of liver and biliary tract, infection, gall stones)

Question 6

list common differentials for a horse with jaundice

Answer 6

• infectious cause
• biliary obstruction
• ragwort poisoning

Question 7

how do you diagnose liver disease in the horse

Answer 7

biochem:
- elevated GGT
- increased AST
- increased bile acids
- incresed bilirubin
- SDH elevation
- increased blood ammonia

Question 8

how do you treat liver disease in horses

Answer 8

• supportive therapy
• antibiotics if infection
• treatment difficult in horses once liver has begun to fail

Question 9

what are some common hx and clinical signs of dogs with liver disease

Answer 9

• yellow mucus membranes/sclera
• dark urine
• lethargy
• vomit/diarrhea
• Pu/PD
• weight loss
• abdo pain/distension
• pyrexia
• neuro signs

Question 10

what are the 3 categories of aeitology and pathogenesis for jaundice in the dog

Answer 10

1. preheptaic = increased RBC destruction (acute and severe)
2. hepatic = function liver disease - unable to conjugate bilirubin so cannot excrete into biliary system
3. post-hepatic = obstruction of biliary system - conjugated bilirubin cannot be excreted into intestines

Question 11

list differentials for preheptatic liver dz

Answer 11

• IMHA
• toxicity
• RBC parasite

Question 12

list common ddx for hepatic dz

Answer 12

• hepatic neoplasia
• toxicity
• lepto
• acute/chronic hepatopathy/cirrhosis

Question 13

list common ddx for post hepatic liver dz

Answer 13

• neoplasia (intestine, pancrease, biliary)
• gallbladder stones/mucocele
• pancreatits

Question 14

diagnostic option for liver disease

Answer 14

• hx and PE
• blood: biochem, hematology, PCV, smear, bile acid stim test
• urinalysis
• abdo US