Liver Function Tests

Question 1

Causes of liver disease

Answer 1

Infection
Adverse drug reaction 
Alcohol abuse
Obesity 
Cancer

Question 2

Normal blood concentrations

Answer 2

Bilirubin 5-17micromol/l
Hepatocellular:
Alanine (ALT) <50iU/l
Obstruction:
Alkaline phosphatase 39-17iU/l
Gamma-glutamyl transpeptidase 0-70iU/l male 0-40iU/l female
Synthetic function: 
Albumin 30-48g/l 
Coagulation INR 1-1.2

Question 3

Stages of haem breakdown

Answer 3

Haem-> iron+globin
     |
Biliverdin
     |
Insoluble bilirubin
      |
Liver
     |
Soluble bilirubin 
Biliary excretion

Question 4

Conditions where bilirubin might be altered

Answer 4

Biliary obstruction (choleostasis)
Hepatocellular damage
Haemolysis

Question 5

Conditions where aminotransferases maybe altered

Answer 5

Hepatocellular damage
Leak out of damaged cells-> large increase in blood
Detection of paracetamol overdose
ALT more specific to liver damage

Question 6

Conditions where Alkaline phosphatase might be altered

Answer 6

Present in canicular and sinusoid membranes of liver
Increased in choleostasis
But also produced by bone and placenta so increased in pregnancy
Raised in infiltration of the liver-> metastasis

Question 7

Conditions where Gamma GT’s might be altered

Answer 7

Present in manny tissues
Increased by induction
Alcohol 
Carbamazepine
Barbiturates
Phenytoin
Rifampincin
Increased in choleostasis 
May be increased in cellular damage
Look at mean corpuscular volume as we'll

Question 8

Conditions where albumin might be altered

Answer 8

Measure of synthetic activity of the liver

Indicates a change over longer term-> 16-24 days

Question 9

International normalised ratio

Answer 9

Prothrombin time
Indicates synthetic activity
Coagulation factors have a short half life so indicates change acute and chronic

Question 10

Hepatitis LFT results

Answer 10

ALT and AST raised 
ALP increased or normal 
Bilirubin increased or normal
GGT increased or normal
Albumin only effected in late stages 
INR raised or normal

Question 11

Cholestasis LFT results

Answer 11

ALP raised
GGT raised 
Bilirubin raised  as not excreted 
ALT and AST raised or normal
Albumin normal, synthetic function not effected by choleostasis 
INR raised or normal

Question 12

LFT chronic liver disease

Answer 12

GGT raised
Bilirubin raised
Albumin decreased
INR increased
ALP, ALT, AST raised or normal

Question 13

Pre hepatic jaundice

Answer 13

Problem before liver
Insoluble bilirubin produced faster than the liver can conjugate it
Haemolytic anaemias such as spherocytosis
Gilbert’s syndrome-> decreased UDP- glucuranosyl transferase-> conjugated bilirubin

Question 14

Hepatocellular jaundice

Answer 14

Transaminases leak out
Liver can’t conjugate bilirubin
Reduced excretion

Question 15

Choleostasis

Answer 15

Cholesterol blockage of bile duct 
Intra hepatic:
Primary biliary cirrhosis-> autoimmune damage to duct
hepatocellular damage
Pregnancy
Extra hepatic:
Gall stones
Cancer in head of pancreas

Question 16

Obstructive jaundice

Answer 16

Choleostasis
GGT and ALP not excreted so are raised
Liver can conjugate but not excrete bilirubin
Water soluble bilirubin excreted in urine

Question 17

Other complications, ascites

Answer 17

Accumulation of fluid in peritoneal cavity
Oedema secondary to hypoproteinaemia
Sodium retention due to secondary hyperaldosteronism
Portal hypertension
Treat with diuretics or surgery

Question 18

Encephalopathy

Answer 18

Neuropsychiatric symptoms 
Personality changes
Disorientation 
Confusion and drowsiness
Sensitivity to centrally acting drugs
Ammonia produced by gut isn't exerted by liver-> reacts with neurotransmitters 
Rx. Neomycin/metronidazole and lactulose

Question 19

Other complications of liver disease

Answer 19

Impaired coagulation
Gastric bleeding rx ranitidine
Bleeding of oesophageal varies rx beta blockers, octreotide

Question 20

Signs of hepatic disease

Answer 20

Jaundice
Pruritis 
Nausea and vomiting 
Hepatomegaly 
Ascites
Spider naevi
Dark urine and pale stools