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Flashcards in Diseases of the liver and pancreas Deck (49)
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1

Which organelle conjugates bilirubin?

Smooth endoplasmic reticulum

2

What are the functions of the liver?

Carbohydrates
- Glycogen storage & synthesis
- Glycolysis & gluconeogenesis

Proteins
- Synthesis & catabolism
- Clotting factors
- Amino acid metabolism &urea synthesis

Lipids
- Lipoprotein & cholesterol synthesis
- Fatty acid metabolism
- Bile acid synthesis

Excretion & detoxification
- Bile acid & bilirubin excretion
- Drug detoxification & excretion
- Steroid hormone inactivation & excretion

Miscellaneous
- Iron storage
- Vitamin A, D, E & B12 storage & metabolism

3

What is measured by LFTs?

Alkaline phosphatase

ALT (alanine aminotransferase)

AST (aspartate transaminase)

Bilirubin

Albumin

Total protein

GGT (glutamyl transferase)

4

What tests might be used for specific liver functions?

Carbohydrate metabolism
- glucose

Protein metabolism
- albumin
- urea
- prothrombin (clotting factors)

Lipid metabolism
- cholesterol
- triglycerides
- bile acids

Excretion and detoxification
- bilirubin
- drugs
- steroid hormones

Misc
- Ferritin (iron storage)
- Prothrombin time (Vit K)

5

What tests give an indication of hepatocyte damage?

Aminotransferases
- Alanine/ALT
- Aspartate/AST
- Found in the cell and only released by cellular damage.

ALT is more specific for liver than AST

AST also found in muscle and red blood cells

Tumour markers – α-fetoprotein (primary hepatocellular carcinoma)

6

What tests give an indication of biliary tract damage?

Impaired excretory function
- Increased Conjugated bilirubin

Increased synthesis of enzymes by cells lining the bile canaliculi
- ALP
- γGT

7

What might be the causes of increased ALP in biliary tract damage?

Cholestasis (intra- or extrahepatic)

Infiltrative diseases

Space-occupying lesions (tumours)

Cirrhosis

8

Which organs also secrete ALP isoenzymes?

Liver

Bone

Intestine

Placenta

9

If γGT and ALP are raised, what might this mean?

A raised γGT supports a liver source of ALP (as opposed to any other isoenzyme).

Elevated due to structural damage

10

What can cause biliary tract damage?

alcohol

enzyme inducing agents
- e.g. anti-epileptics

fatty liver
- e.g. due to alcohol, diabetes or obesity

heart failure

prostatic disease

pancreatic disease
- acute & chronic pancreatitis, cancer

kidney damage
- ARF, nephrotic syndrome, rejection

11

What are the biochemical markers of fibrosis?

ELF score
- PIIINP
- TIMP-1
- Hyaluronic acid

12

What is bilibrubin a measure of?

Excretory capacity of the liver and free flow of bile.

13

What is bilirubin measured as?

Total

Unconjugated
- Pre-hepatic & Hepatic

Conjugated
- Post-hepatic (Obstructive) & Hepatic

14

What serum level of bilirubin is considered to be jaundice?

> 40-50 μmol/L

15

What happens to bilirubin in the liver?

It is conjugated to bilirubin glucuronide by glucuronyl transferase.

16

What protein is bilirubin bound to in the blood?

Albumin

17

What are the pre-hepatic causes of jaundice?

Haemolysis
- e.g. Rhesus incompatibility

Ineffective erythropoiesis
- e.g. spherocytosis

18

What are the post-hepatic (obstructive) causes of jaundice?

Gallstones

Biliary Stricture

Cancer
- i.e. cholangiocarcinoma, head of pancreas

Cholangitis

19

What are the hepatic causes of jaundice?

Unconjugated
- Pre-microsomal
- Microsomal
- Inherited disorders of conjugation e.g. Gilberts, Crigler-Najjar

Conjugated
- Post-microsomal/impaired excretion
- Intrahepatic obstruction
- Inherited disorders of excretion e.g. Dubin-Johnson, Rotor.

20

What are the inborn errors of bilirubin metabolism?

Decreased activity of UDP glucuronyl transferase
- Gilbert’s
- Crigler-Najjar

Reduced ability to excrete bilirubin glucuronide
- Dubin-Johnson
- ROTOR

21

What is the pathway from haemoglobin to bilirubin glucuronide?

Haemoglobin -> bilirubin albumin-bound bilirubin -> bilirubin -> bilirubin glucuronide -> bile duct

22

The patient is jaundiced, their AST/ALT is elevated and their ALP is normal. What will are they likely to have?

Approx 90% of these patients will have hepatitis

23

The patient is jaundiced, their AST/ALT is normal and their ALP is elevated. What will are they likely to have?

Approx 90% will have obstructive jaundice

24

What will urine tests show in prehepatic jaundice?

Unconjugated bilirubin - no urinary bilirubin

25

What will urine tests show in hepatic jaundice?

Variable depending on degree of obstruction due to either disease or inflammatory oedema

26

What will urine tests show in post-hepatic jaundice?

Dark urine (&pale stools)

27

What are the systemic effects of liver disease?

jaundice

oestrogen XS
- gynaecomastia
- spider naevi
- liver palms
- testicular atrophy

bruising

pigmentation

clubbing

dependent oedema

ascites

encephalopathy

osteomalacia / osteoporosis

28

What specific tests can be used in chronic active and autoimmune hepatitis?

Anti smooth muscle, anti liver/kidney, anti microsomal and anti nuclear antibodies

29

What test can be used for primary biliary cirrhosis?

Anti mitochondrial antibodies

30

What test can be used for hereditary haemachromatosis?

Ferritin

transferrin saturation

liver biopsy

genetic testing

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