4.05-4.06 LFT

Question 1

The five liver enzymes?

Answer 1

AST
ALT
LDH (least liver specific)
ALP
GGT

Question 2

What enzyme is implicated in liver gluconeogensis (Cori Cycle) ?

Answer 2

LDH

Question 3

What liver enzyme is involved in drug and xenobiotic elimination at the liver?

Answer 3

GGT (Gamma-glutamyltransferase)

Question 4

High serum AST/ALT > 2 with Oral AST below 300 U/L

Answer 4

Excessive alcohol

Perivenous hepatocytes damaged (zone 3) by alcohol metabolism production of ROS especially at mitochondria (AST) while peiportal ALT spared

Question 5

AST/ALT ~1 (but variable), but absolute amount of enzymes are higher

Answer 5

Drug induced hepatitis

Question 6

AST/ALT often slightly < 1 with some variability, very high both enzymes >500 U/L in more extreme cases

Answer 6

Acute viral hepatitis

High sensitivity, immune system causing the damage

Question 7

What LDH isoform is specific to hepatocytes ?

Answer 7

LDH-5

Question 8

What’s the problem with blood panels of LDH?

Answer 8

Do not distinguish RBC (1) from liver isoforms (5) of LDH & LDH-5 has short half life = underrepresent liver damage
LOW SENSITIVITY

Question 9

What happens to GGT and ALP with heptocellular damage?

Answer 9

Increase moderately

Question 10

What damage is “induced” by alcohol and drugs and present at high levels in bile duct cells ?

Answer 10

GGT

Question 11

What tends to result in a massive increase in both GGT and ALP?

Answer 11

Cholestasis (bile duct obstruction)

Note
Secreted so can increase without hepatocell lysis

Question 12

Where does heme catabolism take place?

Answer 12

Macrophages in liver or spleen

Question 13

Heme is broken down into what during catabolism at the macrophage>

Answer 13

Unconjugated bilirubin (UCB)
Must hitch ride on albumin to reach over *

Question 14

How does bilirubin become conjugated?

Answer 14

1-2 glucoronic acid molecules via UGT enzyme to make conjugated bilirubin more soluble

Question 15

Molecule that can’t measure becomes of its extreme hydrophobic and often underestimates truel levels?

Answer 15

IBL (indirect bilirubin)

Question 16

A mature of CB xD often resuls in overestimation

Answer 16

Direct bilirubin

Question 17

Total bilirubin (TBIL) ?

Answer 17

= UCB + CB

Question 18

What can lead to massive UCB release that often exceed what even the healthiest over can tackle?

Answer 18

Massive RBC hemolysis/premature destruction

Question 19

What conditions can cause in prehepatic jaundice or massive RBC damage?

Answer 19

G6PD or PK deficiencies

Question 20

What kind of jaundice results in increased UCB, highly elevated IBIL, TBIL, CB BUT normal DBIL?

Answer 20

Prehepatic jaundice
(G6PG/PK deficiency)

Question 21

Increased conjugate bilirubin production will lead to what?

Answer 21

Elevated urobilinogen in urine
Stools appear darker b/c stercobilin

Question 22

Sky high LDH but little to no increases in other liver enzymes (jaundice)?

Answer 22

Prehepatic jaundice

Question 23

What is the major effect of hepatic jaundice?

Answer 23

Impaired ability to produce conjugated bilirubin = elevated IBL** + elevated DBIL (hepatocell lysis) + elevated TBIL

Question 24

Higher proportion of the urobilinogen from hepatic jaundice also goes where because of impaired enterohepatic circulation In hepatic jaundice?

Answer 24

Kidneys

Question 25

Generally leads to moderate to significant increases in 5 hepatic enzymes?

Answer 25

Hepatic jaundice

Question 26

Post hepatic jaundice caused most commonly by?

Answer 26

Bile duct obstruction (stones/tumors)

Question 27

Increased DBIL, Normal IBIL, lil to no increase in urobilinogen, sometimes very dark urine from CB, with normal AST, ALT, LDH but very high ALP and GGT (jaundice kind)?

Answer 27

Post hepatic jaundice

Question 28

Chronic obstruction of teh bile duct leads to what?

Answer 28

Post hepatic jaundice OR proliferation of GGT and ALP secreting cells

Question 29

What molecules implies status of CB in the body/cell?

Answer 29

DBIL

Question 30

What molecule implies the status of Unconjugated bilirubin in the body?

Answer 30

IBIL