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Flashcards in Liver Failure Deck (30)
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1
Q

What are the common causes of acute liver failure

A

Paracetamol damage

Sudden loss of synthetic or metabolic functions

2
Q

Describe how paracetamol overuse can cause acute liver failure

A

Free radical damage to the hepatocytes caused by processing paracetamol through an alternative pathway due to blockage from overloading of the normal pathways

3
Q

How may patients survive acute liver failure

A

If they can be kept alive for long enough, their liver may gradually come back into function as there is large regenerative potential
Transplant often the only option

4
Q

What are the common causes of chronic liver failure

A

Cirrhosis
Primary liver cancer - can follow from cirrhosis or happen from other causes such as a hepatitis infection
Secondary liver cancer - metastases, often from bowel cancer

5
Q

Why does liver cirrhosis occur

A

When the liver regenerates, although the cells can regenerate, the liver architect often can’t, so if there is enough fibrosis to lose the normal liver architecture, there will be permanent loss of liver function that will result in cirrhosis

6
Q

What are the common causes of liver cirrhosis (6)

A
Multi factorial aetiology:
Alcohol
Primary biliary cirrhosis
Viral disease - chronic active hepatitis
Autoimmune chronic hepatitis
Haemachromatosis
Cystic fibrosis
7
Q

What are the signs and symptoms of liver cirrhosis

A
Often none
Acute bleed - portal hypertension and oesophageal varices
Jaundice
Oedema and ascites
Encephalopathy 
Spider naevi, pal Mary erythema
8
Q

Why is ascites a sign of cirrhosis

A

When lack of synthetic ability to produce normal plasma proteins, there will be a loss of the plasma oncotic pressure which holds fluid within the blood vessels
As this reduces fluid will more easily move into the tissues and particular from the portal vein into the peritoneum where it accumulates

9
Q

What are spider naevi

A

Small prominent arterioles which develop near the skin and become enlarged and produce a central arteriole with lots of feeder vessels coming away from them
Looks like a spider

10
Q

What is palmar erythema

A

When there is high oestrogen in the blood the patient will develop the pattern of a pale palm surrounded by erythema around the margins of the hand

11
Q

What is ascites

A

Fluid accumulation in the peritoneum due to low plasma protein synthesis producing a lower oncotic pressure within the blood vessels such that fluid moves easily from vessels out into the tissues

12
Q

How is ascites treated

A

Necessary to drain manually to release the pressure it is placing on the thorax

13
Q

What are oesophageal varices

A

Dilated and thin-walled veins in the oesophagus

14
Q

How to oesophageal varices form

A

Blood entering the portal system has no exit route as the portal vein cannot communicate with the hepatic vein so it escapes at the edge of the embryological gut at the lower oesophagus
Blood engorges as it passes through vessels in the lower oesophagus

15
Q

What are the consequences of oesophageal varices

A

May protrude into the oesophageal lumen

Are easy to rupture which will lead to a catastrophic bleed

16
Q

How is a patients survival rate affected if they stop drinking

A

Survival rate significantly reduces even if there is a second cause of liver failure eg - oesophageal varices
This is due to there being some residual liver regeneration that can take place

17
Q

What synthetic functions are lost during liver failure

A

Loss of plasma proteins will lead to problems with ascites and oedema, patient will present with swollen ankles and abdomen
Due to loss of clotting factors, if the patient develops oesophageal varices which then rupture, there is little ability for the blood to be able to clot

18
Q

What metabolic functions are lost in liver failure

A

Loss of first pass metabolism
Products of the metabolism which are toxic to the brain will not be removed and will pass, causing encephalopathy
Failure of conjugation of bilirubin will lead to jaundice

19
Q

What different tests can be used for liver function

A

Hepatic enzyme level tests - ALT, GGT

INR - most useful

20
Q

Why can hepatic cell enzyme levels be used to test liver function

A

These enzymes will escape if there is damage or inflammation more easily that if there is health in the liver
If inflammation in the liver, these enzymes will be detected more in the blood

21
Q

Why are hepatic cell enzyme tests not always useful

A

If there is a large liver producing a normal amount of enzymes we may find raised levels even though the liver is healthy
Similarly a fibrosed liver may produce a lot of hepatic enzymes but the levels measured are actually normal as there are fewer cells producing a higher amount of enzyme

22
Q

What is INR

A

Measures time taken for prothrombin to form thrombin and compares it against a control

23
Q

What is a normal INR for a patient taking warfarin

A

2-4

24
Q

What is considered a high INR for a patient with liver failure

A

1.2-1.3

25
Q

What are the effects of liver failure

A

Fluid retention - ascites and oedema
Raised INR as the liver is no longer synthesising clotting factors effectively
Portal hypertension leading to oesophageal varices
Inability to remove waste products leading to encephalopathy
Build up in the blood of unconjugated bilirubin leading to jaundice

26
Q

What treatment options are available for liver failure

A

Managing things such as alcohol consumption and infection are very important
Transplantation is the only cure
Artificial liver systems are not yet available but are starting to provide some degree of liver function

27
Q

Describe how a live transplant donor can be used in a liver transplant

A

When a liver is donated, each liver has 3 lobes each of which can be transplanted into separate people
Therefore a single lobe can be removed from a live donor and transplanted

28
Q

Why are live donor liver transplants very risky

A

It requires good division of major blood vessels supplying each lobe and that these can be identified
If this is not the case there will be catastrophic bleeding and it is likely the donor will die as a consequence

29
Q

What must a dentist remember when treating a patient at risk of liver failure (Metabolic consequences)

A

Sedatives are going to be a problem and giving IV sedation out of hospital may be risky
May be necessary to reduce doses of normal medicines because of accumulation
Paracetamol often the safest option as NSAIDS will increase bleeding risk
Always ask the physician

30
Q

What must a dentist remember when treating a patient at risk of liver failure (Synthetic consequences)

A

Remember bleeding tendency, drug binding may be reduced and there may not be gamma globulin synthesis
LA are largely metabolised in the plasma such as articaine and therefore don’t pose a problem