Liver Diseases Flashcards
What is the most common reason why acute liver failure occurs?
Tends to happen when there is a sudden insult to the liver and liver function loss is RAPID
What is an example of acute liver failure?
paracetamol poisoning
Define ‘paracetamol poisoning’
= free radical damage to hepatocytes caused by processing paracetamol through an alternative pathway.
= due to a blockage or overloading of normal pathways
What are hepatocytes?
Specialised epithelial cells- make up 80% of liver mass
(Paracetamol poisoning) What are the options for treating this early in the process- which drug can be given if an overdose is detected?
= can be assessed by blood sample to determine risk
= liver metabolic pathway for paracetamol follows zero order kinetics ( the rate of reaction does not depend on the reactant concentration)
= acetylcysteine can be given if there is a risk of damage above recommended dose- as this is given to block alternative pathways
What 2 things will happen when there is a sudden loss of liver function?
=the liver has both synthetic and metabolic functions: both of these will stop
= the ability to make proteins and clotting factors will be lost and ability to decontaminate the blood from toxic substances will be lost
In acute liver failure: Due to the sudden loss of liver function when and what can cause rapid death?
= within 5-7 days
= bleeding risk (most likely to lead to death)
= encephalopathy - impairment of brain function cause by high levels of toxins in the blood
Does the liver usually recover after acute liver failure?
Yes- given time
What is often the only option for patients suffering from acute liver failure?
liver transplant (within a few days)- often not possible
What may happen if a patient suffering from acute liver failure is kept alive for a period of time ?
Their own liver may come back into function
What are 3 examples of chronic liver failure?
= Cirrhosis
= primary liver cancer
= secondary liver cancer
What is Cirrhosis? (simple definition)
= disordered architecture of the liver
How can primary liver cancer occur?
= can follow on from cirrhosis
= or can happen due to hepatitis virus infection
How might secondary liver cancer occur?
Can be metastatic (development of secondary malignant growths at a distance from the site of primary cancer)
= particularity from bowel tumours where cells from cancer can be washed through portal system and embedded themselves in liver where they grow
Cirrhosis is a mixed picture of……… , ……… , …… of liver structure ?
= damage
= fibrosis
= regeneration
Describe Cirrhosis in more detail?
= damage to hepatocytes
= once damage stopped the liver regenerates (happens when insufficient damage to cause ALF but enough that a proportion of the liver is gradually lost each recovery
= when the liver is regenerated (although cells can regenerate) the liver architecture often cannot (standard portal triad may not be regenerated properly)
Describe the multi-factorial aetiology of cirrhosis: (6 points)
= alcohol
= primary biliary cirrhosis (autoimmune disease)
= viral disease (hep b&c (chronic active hepatitis) virus is never controlled or cleared continues to replicate)
=autoimmune chronic hepatitis
= heamachromatosis (iron levels build up slowly)
= cystic fibrosis
Give an example of a patient who may be at a higher risk of cirrhosis?
if a patient had a tendency towards haemochromatosis and also was a heavy drinker
What are the key signs and symptoms of Cirrhosis?
= NONE
= Acute bleed- portal hypertension
= ascites and oedema
= jaundice
= spider naevi/ palmar erythema
= encephalophathy
(Cirrhosis) Why might an acute bleed be a symptom of Cirrhosis?
= portal hypertension, elevated pressure in portal venous system, the portal vein is a major vein which leads to the liver, blood vessels around oesophagus to swell (oesophageal varices)
Why might jaundice by a symptom of Cirrhosis?
= related to the livers ability to produce bilirubin
= if fewer liver cells are able to correctly process bilirubin, conjugated and pass it to the biliary tree. chances of jaundice are higher
Why might ascites be a sign of cirrhosis?
= when lack of synthetic-ability of liver to produce normal plasma proteins there will be a loss of plasma oncotic pressure (the osmotic pressure generated by large molecules (especially proteins) in solution ) which holds fluid within the blood vessels
=as this reduces as the protein pressure falls, fluid will more easily move into the tissues
= in particular, from the portal vein into the peritoneum where it will accumulate (ASCITES)
Why might encephalopathy be a sign/symptom of Cirrhosis?
= brain impairment due to toxic materials within the blood, will happen as the liver function fails to remove these (leads to death)
What are spider naevi and palmar erythema a result of?
- high oestrogen levels are seen because oestrogen metabolism is not taking place
How does spider naevi present?
= small prominent arterioles which develop near the skin
= become enlarges and produce a central arteriole with lots of feeder vessels coming away from there
How does Palma Erythema present?
= no known aetiology
= pale palm surrounded by erythema around the margins of the hand
What is ascites? (simple definition)
= fluid accumulating in the peritoneal area, around the bowel
Why does ascites occur?
=lower plasma protein synthesis and lower oncotic pressure within blood vessels
= fluid easily moves from blood vessels out into the tissues (in this case peritoneum) where is accumulates as liquid
Describe the pressure caused in ascites?
High Portal venous pressure
How can ascites be fixed?
fluid drained manually to release the pressure that it is placing on the thorax
What are oesophageal varices?
= dilations of the little veins at the bottom end of the oesophagus
What 2 types of function can be lost in liver failure?
= synthetic
= metabolic
What 2 main things are included in the loss of synthetic function in liver failure?
= plasma proteins synthesis will lead to ascites and oedema
= loss of clotting factors
What is meant by the loss of clotting factors in liver failure?
= loss of synthetic function
= if patient develops oesophageal varices which then rupture there is little ability for the blood to be able to clot itself (often terminal event)
Describe loss of metabolic function (liver failure)? (3)
=medicines will be unpredictable
= detoxification
=failure of conjugation of bilirubin will lead to the characteristic jaundice
Describe detoxification in the loss of metabolic function in liver failure?
= products of metabolism which are harmful to the brain will not be removed and therefore will pass to cause encephalopathy, potential toxicity
What does the failure of conjugation of bilirubin lead to?
Jaundice
How is red blood cell haemoglobin broken down and how does it become bilirubin?
=haemoglobin is broken into heme and globin
= heme breaks down into iron and biliverdin (green pigment)
= biliverdin is then transformed into bilirubin (orange pigment)
What do liver function tests measure?
the degree of liver inflammation
What do liver function tests usually look at?
= the ability of the liver enzymes to escape from the cell like ALT (alkaline transaminase) and GGT (Gamme-glutamyl)- these enzymes will escape the liver cells if they are damaged or inflamed more easily than if they are healthy
What do liver function tests usually look at?
= the ability of the liver enzymes to escape from the cell like ALT (alkaline transaminase) and GGT (Gamme-glutamyl)- these enzymes will escape the liver cells if they are damaged or inflamed more easily than if they are healthy
What is the most useful test for determining liver function?
= INR
Why is the INR the most useful test for liver function?
= based upon synthesis of clotting factors and therefore is synthesis is impaired as liver function is impaired then the INR will change
What scenario may there be a raised liver function test result however nothing is wrong with the patient
= enlarged liver producing normal amount of enzymes
what scenario might there be a normal liver function test result however the liver is damaged?
= small fibrosed liver which is producing a lot of hepatic enzymes- fewer cells producing a higher amount of enzymes
What does the INR measure?
= measured prothrombin time against a control (lab worker/volunteer)
= prothrombin -> thrombin
What is a normal value of INR/
1.0
Normal value of INR if patient is on warfarin?
- therapeutic range is 2-4
What does it mean if the INR is not 1?
significant liver synthetic dysfunction (not enough clotting factors)
Give 2 examples of fluid retention?
=ascites
= ankle oedema
Why might a patient suffering from liver failure have a raised INR?
the liver is no longer synthesising clotting factors effectively- prolonged bleeding
Why is portal hypertension a result of liver failure?
- blood is unable to leave portal veins and enter hepatic vein, escapes at edge pf embryological gut and lower oesophagus to form these thin-walled oesophageal varices
- inability of GI blood to re-enter the vena cava
- leads to oesophageal vein dilation
In liver failure- what can the inability to remove waste lead to?
encephalopathy
What can build-up of haembreakdown products lead to ?
jaundice (unconjugated bilirubin)
How can liver failure be treated?
= identify patients at risk of developing liver failure
= reduce rate at which damage is happening
= supportive
= transplantation
