LFTs

Question 1

what are the hepatic enzymes in LFTs?

Answer 1

serum transaminases (ALT/AST)
Alkaline phosphatase
Gamma Glutamyl Transpeptidase

Question 2

what are the indicators of intrinsic synthetic function?

Answer 2

albumin
Prothrombin time
Bilirubin

Question 3

hepatic enzymes are usually intracellular, when are they released from hepatocytes?

Answer 3

hepatocellular injury

Question 4

what do hepatic enzymes do?

Answer 4

catalyse gamma-amino acids

Question 5

how does damage affect aminotransferase?

Answer 5

often raised in all aetiologies/hepatocellular pathologies

usually less than 500 in obstructive jaundice

Question 6

what does ALP do?

Answer 6

enzyme that catalyses the hydrolyses of a number of organic phosphate esters

Question 7

what is the pathway of bilirubin?

Answer 7

breakdown of haem
transported to liver bound to albumin
uptake into hepatocytes
undergoes conjugation
excreted via urine/faeces

Question 8

what is isolated hyperbilirubinaemia?

Answer 8

high bilirubin either conjugated or unconjugated

Question 9

what clotting factors does the liver synthesise?

Answer 9

factor 1 (fibrinogen)
factor 2 (prothrombin)
5
7
9
10
13

Question 10

what does prothrombin time measure?

Answer 10

conversion time from PT to thrombin

Question 11

what does elevated PT indicate?

Answer 11

reduced synthetic functionality

Question 12

what can cause elevated PT?

Answer 12

Drugs (warfarin)
bile malabsorption - Vit K deficiency (common in gall stones, cholangitis)
consumptive coagulopathy

Question 13

important history Questions?

Answer 13

use/exposure to chemicals/drugs
accompanying symptoms
parenteral exposures (tattoos, sex, blood transfusions, snorting drugs)
travel history
alcohol exposure
occupational exposure
temporal variation (eg. cholestatic = itchy at night)

Question 14

name some drugs that can cause deranged liver tests

Answer 14

antibiotics
antidepressants
statins
NSAIDs
Anti-epileptics
Anti-TB (anti-TNF alpha)
sulphonamides/sulphonylureas
Over the counter

Question 15

ALT/AST > Bili N/?

Answer 15

hepatocellular

Question 16

ALP > ALT/AST

Increased Bili?

Answer 16

cholestasis

Question 17

increased PT/INR?

Answer 17

prolonged jaundice/vit K malabsorption

hepatocellular dysfunction

Question 18

Albumin means?

Answer 18

difficult to isolate

Question 19

what is the picture of acute hepatocellular injury?

Answer 19

AST:ALT ration more than 0.8
need acute liver screen for hepatitis, HIV and other viruses (consider HSV if pregnant)
Doppler ultrasound
review medications
possible hypertension

Question 20

what mimic/overlap conditions can cause raised AST:ALT?

Answer 20

coeliac disease
muscle disorders
adrenal sufficiency
anorexia
thyroid

Question 21

how can you exclude coeliac disease?

Answer 21

tTG - IgA
consider HLA testing
gold standard = biopsy

Question 22

what is caused by unconjugated hyperbilirubinaemia?

Answer 22

increased bilirubin production
impaired hepatic bilirubin uptake
impaired bilirubin conjugation

Question 23

what can cause impaired bilirubin uptake in hepatocytes?

Answer 23

heart failure
portosystemic shunts
drugs - rifampicin, probenacid

Question 24

what canc cause impaired bilirubin conjugation?

Answer 24

gilberts/CN type 2
hyperthyroidism
liver disease

Question 25

what occurs with conjugated hyperbilirubinaemia?

Answer 25

Extrahepatic cholestasis (biliary obstruction)
Intrahepatic cholestasis (cirrhosis, sepsis,TPN, hepatitis)

Question 26

what are the signs of acute liver failure?

Answer 26

jaundice
encephalopathy
..

Question 27

what is a cholestatic picture in LFTs?

Answer 27

raised alkaline phosphatase
raised bilirubin (not always a huge amount)

Question 28

what can CMV and EBV virus cause?

Answer 28

splenomegaly