Lecture 11 - Jaundice

Question 1

How does jaundice present itself?

Answer 1

Yellow discolouration of the skin, eyes and other tissues.

Question 2

What causes Jaundice?

Answer 2

A buildup of bilirubin in tissue fluids and bloodstream.

Question 3

How would you diagnose liver disease?

Answer 3

Performing liver function tests.

Question 4

What levels would you look at on a liver function test?

Answer 4

• Bilirubin
• Liver enzymes (AST/ALT)
• Hepatobiliary enzymes (gGt/Alk, Phos)
• Albumin
• Total protein
• Autoantibodies/antibody titre
• Haematology
• Viral markers
• Metabolic indicators
• Tumour markers

Question 5

How much bile is produced per day?

Answer 5

About 0.5L per day

Question 6

What produces bile?

Answer 6

Hepatocytes

Question 7

How often is bile recycled?

Answer 7

6-8 times a day to recycle bile salts

Question 8

How much bile is stored in the gallbladder?

Answer 8

100ml

Question 9

What is bile involved in?

Answer 9

• Released into the intestine on demand
• Emulsification of fat in the intestine
• Fat soluble vitamin uptake (A, D, E, K)
• Excretion of substances which can’t be cleared by kidney’s (cholesterol, bilirubin)

Question 10

What is bilirubin a product of?

Answer 10

• Haem catabolism

- From red blood cells, myoglobin, cytochromes and peroxidases

Question 11

How much bilirubin is produced per day?

Answer 11

250-300mg

Question 12

What is the pathway of bilirubin?

Answer 12

• Transported to the liver carried by albumin
• In the liver, it is conjugated with glucuronic acid by UDP glucuronyltransferase (water soluble when conjugated).
• Metabolised by b-glucuronidase in the gut to form urobilinogens
• Some of these are reabsorbed and sent back to the liver and some are excreted in urine.

Question 13

What are the steps of bilirubin metabolism?

Answer 13

(1) Production
(2) Uptake by the hepatocyte
(3) Conjugation
(4) Excretion into bile ducts
(5) Delivery to the intestines

Question 14

What are the three causes/types of jaundice?

Answer 14

• Prehepatic
• Intrahepatic
• Extrahepatic

Question 15

What causes pre-hepatic jaundice?

Answer 15

Conditions that heighten your blood’s rate of hemolysis. Because the bilirubin can only process so much bilirubin at once, bilirubin overflows into bodily tissues.

Question 16

Symptoms of pre-hepatic jaundice?

Answer 16

Increased bilirubin (unconjugated) in blood but normal AST/ALT, normal ALP/gGT in the liver

Question 17

Liver symptoms in anaemia?

Answer 17

• Gallstones
• Hepatomegaly, splenomegaly
• AST/ALT elevated
• Thrombosis
• Iron overload
• Hepatic thrombosis
• Coagulated deficit
• Altered MRI signal

Question 18

What syndrome can prehepatic jaundice result in?

Answer 18

Gilbert’s Syndrome

Question 19

Describe neonatal jaundice

Answer 19

• Up to 90% of babies, more if premature.
• Delays in clearance of bilirubin from red cell breakdown.
• Treated by phototherapy
• Only a concern if persists and is accompanied by pale stool/dark urine.

Question 20

Describe hepatic jaundice

Answer 20

• Normal haem metabolism so normal bilirubin in the liver
• ## Increased bilirubin and raised AST/ALT and mild increase in ALP/gGT in the liver –> results in liver disease

Question 21

What is viral hepatitis?

Answer 21

• Viruses selectively infect hepatocytes
• Very strong immune response causes severe hepatitis (A-E)
• Immune system then kills the infected hepatocytes

Question 22

Describe post-hepatic jaundice

Answer 22

• Passage through the bile ducts are blocked
• Leaks into circulation
• Conjugated bilirubin is soluble so is excreted in the urine.
• Increased bilirubin, modest increase in AST/ALT, raised ALP/gGT
• Obstruction of bile ducts due to gallstones, disease of the ducts