Lecture 12- Jaundice and liver function tests (LFTs)

Question 1

Jaundice

Answer 1

= clinical manifestation of increase bilirubin the blood

• Yellow discolouration of sclera and the skin

Question 2

• When Hb goes to the Spleen it is broken down into haem and globin
  *

Answer 2

• Globin
• Haem

Question 3

haem metabolism

Answer 3

• Converted to biliverdin (unconjugated)
• Transported via albumin to the liver
• Liver conjugates bilirubin with glucuronic acid to make it water soluble
  
  1. Can enter entero- hepatic circulation
  2. Can travel down to duodenum and stay in the gut à oxidised to stercobilin – makes faecal matter brown
  3. Can go to the kidney and be excreted as urobilinogen

Question 4

causes of jaundice

Answer 4

1. pre-hepatic
2. hepatic
3. post-hepatic

Question 5

pre-hepatic jaundice

Answer 5

• Too much break down of HB –> haem
• Too much demand for liver
• Liver cant conjugate it all
• Therefore some bilirubin is unconjugated

Question 6

what can cause increased breakdown of Hb

Answer 6

• Haemaglobinopathies
  
  • Sickle cell
  • Thalamasemia
  • Spherocytosis
• Haemolysis

Question 7

hepatic jaundice

Answer 7

• Liver function down (reduced hepatocyte function)
• Reduced conjugating ability of the liver

Question 8

causes of hepatic jaundice

Answer 8

Chronic liver disease

Acute liver damage

Question 9

post hepatic jaundice

• Any obstructive condition to the bile duct à if any part of excretion pathway is obstructed e.g. gall stones
• Most common

Question 10

which type of bilirubin (conjugated or unconjugated) will be raised if cause is post-hepatic

Answer 10

• Type of bilirubin likely to be raised is conjugated –> water soluble –> goes through blood stream to the kidney
  
  • More bilirubin excreted by the kidney
  • Therefore discolouration of the urine
    
    • Dark urine, pale stools

Question 11

post hepatic causes

Answer 11

• Gall stones
• Inflammation which causes scarring or narrowing of the biliary tree
• Enlargement of the head of the pancreas (pancreatic carcinoma)à painless jaundice (red flag)
• Intrahepatic obstruction within the liver
  
  • Inflammation/ oedema
  • Tumour e.g. hepatocellular carcinoma (compression locally)
• Cirrhosis- no expansile
  
  • Compresses veins – portal hypertension
  • Also compresses bile ducts in liver

Question 12

what is included in a liver function test

Answer 12

• albumin
• ALT
• AST
• ALO
• Bilirubin

Question 13

albumin levels represent

Answer 13

synthetic function of the kidney

• can have renal causes too

Question 14

damage to the liver causes an increase in which enzymes being released into the plasma

Answer 14

ALT

AST

Question 15

ALT

Answer 15

• More specific to liver ‘L’
• Acute liver damage (likely for them both to go up)

Question 16

• AST

Answer 16

• Aspartate transaminase
  
  • Also found in cardiac (increased troponin) and skeletal muscle (look at increase in CK) and RBC (FBC)
  • Chronic liver damage (likely for them both to go up)

Question 17

• ALP- alkaline phosphatase

Answer 17

• Bile ducts in the liver blocked (cholestasis)
• Can be high in children that are growing quickly/ also malignancy of bone
• Gamma-glutamyl transferase - another enzyme which will confirm if the raised ALP are caused by a damaged or obstructed bile duct as opposed to the bone

Question 18

• Bilirubin

Answer 18

• Conjugated vs unconjugated
  
  • Unconjugated
    
    • Neonatal jaundice
    • Unconjugated bilirubin can cross the BBB
      
      • Damage to the brain

Question 19

Indications for LFTs

Answer 19

• Healthy (baseline LFTS)
• Liver conditions (monitor)
• Suspected liver pathology

Question 20

e.g. Women with abdominal pain and looks jaundiced. Ultrasound shows obstructed CBD

Answer 20

• Post-hepatic jaundice
• Obstructive pattern on LFT

Question 21

e.g. Man with vomiting and jaundice

• Acute vital hepatitis
• Hepatic jaundice
• Hepatocellular damage on LFTs

Answer 21

• Must be pre-hepatic
• Increased unconjugated bilirubin (abnormality in red blood cells –> look at FBC e.g. haemolytic anaemia)

Question 22

if increase in uncongugated bilirubin

Answer 22

must be pre-hepatic cause

• would be hepatic of post-hepatic if conjugated

Question 23

e.g. Paracetamol overdose

Answer 23

• Hepatocellular damage indicated by high AST/ALT
• Hepatic cause

Question 24

e.g. Severe epigastric pain and vomiting

Answer 24

• Common bile duct obstruction
• Stone obstruction after pancreatic duct
• ALP will be high due to damage to bile duct cells

Question 25

increased ALP indicates

Answer 25

obstructive pattern- gall stones

Question 26

e.g. no sign of jaundice

Answer 26

* Obstructive pattern but no jaundice yet

Question 27

e.g. mixed picture

Answer 27

* Think of the clinical picture * Some liver problems can show a mixed picture * Hepatocellular (cancer can cause direct damage to hepatocytes) and obstructive damage (cause compression to bile duct cells) * Both hepatic and post-hepatic causes * GI cancer has metastasises to the liver (most common cause of this mixed picture)

Question 28

What clinical signs might be evident if the Liver is unable to synthesise Albumin?

Answer 28

oedema--\> ascites

Question 29

In basic terms why might someone with Liver disease become confused?

Answer 29

build up of ammonia which is toxic to the brain

Question 30

In simple terms what is thought to be the aetiology of Non- alcoholic fatty liver disease (NAFLD)?

Answer 30

insulin resistance increase the amount of glucose converted to TAF - deposited in the liver

Question 31

In simple terms what is thought to be the aetiology of Non- alcoholic fatty liver disease (NAFLD)?

Answer 31

wilsons

Question 32

In basic terms, how is the Portal circulation different to the Systemic circulation?

Answer 32

goes through the liver

Question 33

What potential complications of portal hypertension can result in haematemesis?

Answer 33

oesophageal varices

Question 34

What duct is formed when the right and left hepatic ducts join as they exit the Liver?

Answer 34

common hepatic duct

Question 35

In simple terms, what is the underlying problem in prehepatic jaundice

Answer 35

higher breakdown of haem related to high amount of billirubin too much for the liver to conjugate mixed conjugated and unconjugated billirubin in blood test

Question 36

What classification of hyperbilirubinaemia do you get in Hepatic jaundice?

Answer 36

hepatic and post-hepatic

Question 37

State two common causes for Post-Hepatic jaundice

Answer 37

gall stones strictures of biliary tree

Question 38

What might a patient notice about the colour of their faeces if they have Post-Hepatic jaundice?

Answer 38

pale

Question 39

What measurement included in Liver Function Tests actually measures Liver function

Answer 39

ALT- most specific to hepatocellular damage

Question 40

Following contraction of the gallbladder, what structures does Bile pass through on its journey to the duodenum?

Answer 40

common bile duct and ampulla of vater into the 2nd part of the duodenum

Question 41

Briefly describe the potential effects of excess alcohol on the Liver over a period of: * Weeks * Years * Decades

Answer 41

* Weeks- fatty liver (reversible) * Years- alcoholic hepatitis * Decades- cirrhohis

Question 43

In simple terms explain how varices can form in the GI tract

Answer 43

due to protal hypertension - fibrosiss of live means the liver cannot expand- therefore veisn that enter the liver will be compressed - increased BP in portal system therefore blood shunts from portal system tp the systemic ciruclation via anastomes

Question 44

escribe the effects of portal hypertension on kidney function in Hepatorenal syndrome

Answer 44

decreased renal function activation of symapthetic nervous system results in renal vasoncstriction and therefore reduced renal blood flow, reduced GFR - renal failure , even acute tubular necrosis (ATN)

Question 45

Explain why you get dark urine in Post-Hepatic jaundice

Answer 45

- conjugated bilirubin (dark brown) is water soluble therefore can go intot he blood stream to the kidney - post-hepatic jaundice means there is a blockage into the GI system therefore less excreted in faeces and more goes into the blood and filtered by the kidneys

Question 46

What can cause a raised ALP (Alkaline Phosphatase) level on a Liver function test?

Answer 46

damage to the lining of the biliary tree

Question 47

1. Explain to a friend (in stages) how chronic alcohol misuse can eventually result in the formation of abdominal ascites

Answer 47

1. increased fat depsoiton in the liver 2. overtime increase in inflmamaortry cell influx * chronic inflammation * cirrhosis 3. decrease expandability of liver * compressed protal vein * increased portal hypertension 4. less albumin produced 5. ascites

Question 49

Explain to your friend (yes the one trying to ignore you right now) how hepatocellular injury can lead to a mixed conjugated and unconjugated hyperbilirubinaemia

Answer 49

hepatocellular disease can cause a mixed unconjugated and conjugated hyperbilirubinemia due to both impaired bilirubin conjugation and canalicular excretion drgrvtd in conjugated bilirubin excretion cause isolated conjuagted hyperbilirubinemia without cholestasis

Question 50

cholestasis

Answer 50

Cholestasis is a liver disease. It occurs when the flow of bile from your liver is reduced or blocked. Bile is fluid produced by your liver that aids in the digestion of food, especially fats. When bile flow is altered, it can lead to a buildup of bilirubin.

Question 51

(i) Name two of the three paired salivary glands (2x 1⁄2 marks)