chempath tutorial 3 - jaundice & liver function tests

Question 1

What are the visible manifestations of jaundice?

Answer 1

Yellowing of the skin, mucus membranes and the sclera of the eyes

Question 2

Why may transient jaundice occcur in a premature infant?

Answer 2

Their bilirubin conjugating systems are immature, and there will be increased breakdown of fetal red blood cells releasing bilirubin

Question 3

What happens to plasma levels of total bilirubin in haemolytic anaemia?

Answer 3

Increases

Question 4

What happens to plasma levels of unconjugated in haemolytic anaemia?

Answer 4

Increases

Question 5

What happens to plasma levels of conjugated bilirubin in haemolytic anaemia?

Answer 5

Stays normal

Question 6

What happens to levels of urine urobilinogen in haemolytic anaemia?

Answer 6

Increases

Question 7

What happens to levels of urine bilirubin in haemolytic anaemia, and why?

Answer 7

Not present (because urine bilirubin is conjugated, but levels of conjugated do not rise in haemolytic anaemia because hepatobiliary function is normal

Question 8

What happens to plasma levels of total bilirubin in cholestasis?

Answer 8

Increase markedly

Question 9

What happens to plasma levels of unconjugated in cholestasis?

Answer 9

modest increase or stays normal

Question 10

What happens to plasma levels of conjugated bilirubin in cholestasis?

Answer 10

Marked increase

Question 11

What happens to levels of urine urobilinogen in cholestasis?

Answer 11

Decreases

Question 12

What happens to urine bilirubin levels in cholestasis?

Answer 12

They increase/is present

Question 13

Why do urobilinogen levels in the liver decrease with cholestasis?

Answer 13

There is less conjugated bilirubin being excreted into the intestines and converted to urobilinogen, and therefore a decreased level in theurine

Question 14

What is the difference between bile pigments and bile salts?

Answer 14

Bile pigments are the coloured derivatives of the breakdown of Haem, while bile salts are derived from cholesterol and are used in lipid digestion and absorption

Question 15

How do plasma cholesterol levels change with cholestasis?

Answer 15

Tend to rise

Question 16

How do plasma cholesterol levels change with chronic hepatocyte damage?

Answer 16

Fall

Question 17

In what sorts of liver disease is the determination of the activities of aspartate and alanine aminotransferases (AST and ALT) in plasma useful as a diagnostic acid?

Answer 17

when there has been liver cell damage or necrosis, especially acute

Question 18

In what sorts of liver disease is the determination of the activities of alkaline phosphatase and gamma glutamyltransferase in plasma useful as a diagnostic acid?

Answer 18

Cholestasis (intrahepatic or extrahepatic), alcoholic liver disease

Question 19

What type of jaundice does cirrhosis cause?

Answer 19

Intrahepatic obstructive jaundice

Question 20

How can a liver function test differentiate cirrhosis from acute hepatitis?

Answer 20

In acute hepatitis, there is no change in the ability of the liver to produce proteins, so albumin levels will be normal, while they will be markedly low in a poorly functioning cirrhotic liver.

Question 21

In a case of extrahepatic biliary obstruction, what would you expect the levels of plasma alanine aminotransferase to be?

Answer 21

Mildy/moderately elevated

Question 22

In a case of extrahepatic biliary obstruction, what would you expect the levels of plasma cholesterol to be?

Answer 22

elevated due to failure to excrete

Question 23

In a case of extrahepatic biliary obstruction, what would you expect the levels of prothrombin to be?

Answer 23

low

Question 24

In a case of extrahepatic biliary obstruction, what would you expect the levels of gamma glutamyl transferase to be?

Answer 24

High

Question 25

In a case of extrahepatic biliary obstruction, what would you expect the levels of urine bilirubin to be?

Answer 25

high

Question 26

In a case of liver cirrhosis, what would you expect the levels of plasma alanine aminotransferase to be?

Answer 26

Mildy/moderately elevated (may be normal)

Question 27

In a case of liver cirrhosis, what would you expect the levels of cholesterol to be?

Answer 27

Low due to cell damage reducing synthesis

Question 28

In a case of liver cirrhosis, what would you expect the levels of prothrombin to be?

Answer 28

Low

Question 29

In a case of liver cirrhosis, what would you expect the levels of gamma glutamyl transferase to be?

Answer 29

High, if alcoholic liver disease present

Question 30

In a case of liver cirrhosis, what would you expect the levels of urine bilirubin to be?

Answer 30

elevated

Question 31

What is bilirubin bound to in the blood?

Answer 31

Albumin

Question 32

What are the 3 key ways that drugs may lead to jaundice?

Answer 32

1. Promote haemolysis
2. Inhibit bilirubin conjugation
3. Damage liver cells/cause hepatitis reactions/cause cholestasis

Question 33

Why is prothrombin concentration reduced in patients with cholestasis?

Answer 33

Because of a lack of absorption of Vitamin K, which is a fat soluble vitamin, because of limited secretion of bile salts into the intestine that are required for lipid digestion/uptake.

Question 34

Why can increased prothrombin time in a patient with jaundice be reversed with Vitamin K in cases of cholestasis, but not cirrhosis?

Answer 34

With cholestasis, issue is low vitamin K to activate clotting factors, which can be reversed with infusion.
In cirrhosis, there is liver damage reducing the number of factors being produced, meaning vitamin K will not help.