Pathology Liver Flashcards
How does oxygen tension change across the hexagonal structures in the liver?
Oxygen tension is greater at the peripheries near the mini portal triad and this decreases as you move across the mid acinar zone towards the central vein.
=> Periportal an pericentral hepatocytes have slightly different functions
Which cells of the liver are most vunrable to injury?
Pericentral cells
The liver has a large functional reserve- how much can be removed and the liver heal entirely be restitution?
Approximately half of the liver
How long does it take for a liver to cirrhose?
At least 20 years
What is cirrhosis?
Terminal fibrosis of the liver
What are the causes of acute liver failure (jaundice)?
Acute onset Hep A/B
Alcohol
Drugs
Bile duct obstruction
What is Acetoaminophen toxicity?
Paracetamol overdose producing confluent necrosis
What are the consequences of acute liver failure?
1) Complete resolution
2) Chronic liver disease (alcoholics or chronic hepatitis B/C)
3) Death from liver failure
Do all patients with severe liver disease have jaundice?
No
What does the liver do to bilirubin?
Conjugates it
What is pre hepatic jaundice?
Where there is too much haem to break down
What causes prehepatic jaundice?
Haemolytic anaemias (sickle cell)
Prehepatic jaundice: Conjugated or unconjugated bilirubin?
Unconjugated
What is hepatic jaundice?
Liver cells injured or dead
What are the causes of hepatic jaundice?
Acute liver failure Alcoholic hepatitis Cirrhosis (decompensated) Pregnancy Autoimmune (Primary biliary cirrhosis, Primary sclerosing cholangitis)
What is post hepatic jaundice?
Where bile cannot escape into the bowel
Post hepatic jaundice: conjugated or unconjugated bilirubin?
Conjugated bilirubin
What are the causes of post hepatic jaundice?
Congenital biliary atresia
Gallstones blocking CBD
Strictures in CBD
Tumours (head of pancreas or cholangiocarcinoma
Is cirrhosis reversible?
No- its the primary end point for all liver disease.
What does cirrhosis look like?
Bands of fibrosis separating regenerative nodules of hepatocytes. The blood which enters the liver cannot be filtered and the proteins produced by the liver cannot be secreted due to the alteration of hepatic microvasculature.
Common causes of cirrhosis?
Haemochromatosis (iron overload) Autoimmune (PSC, PBC) Alcohol Hepatitis Gall stones
What are the complications of cirrhosis?
1) Portal hypertension
2) Ascites
3) Liver failure- not carrying out its functions, detoxifying, producing proteins
4) HHC
Why is ascites a complication of cirrhosis?
Liver is not producing enough albumin which lowers the osmotic pressure in the circulation so much of the plasma water can enter the peritoneal cavity
What are the consequences of portal hypertension?
Portocaval anastamosis issues:
1) Oesophageal varacies
2) Caput medusa
3) Haemorrhoids (rectal varacies)
What are the causes of portal hypertension other than cirrhosis?
Portal fibrosis
Portal vein thrombosis
What are the features of cirrhosis and what are the causes of these features?
Oedema: Hypoalbuminaemia
Ascites: Portal hypertension and hypoalbuminaemia
Haematemisis: Oesophageal varacies (portal hypertension)
Spender navi (Hypoeostrogenism)
Bleeding and bruising (reduced clotting factor synthesis)
Coma- inability to eliminate toxic bacteria
Infection: reduced Kupffer cell number and function
What is the pathophysiology of alcoholic liver disease?
Alcohol causes increased peripheral release of fatty acids and increased synthesis of fatty acids and triglycerides within the liver.
Acetylaldehyde, a product of alcohol metabolism is toxic to liver cells
Alcoholic fatty liver is reversible and forms over what time scale?
A few days- liver turns pale fatty lump. Steatosis
Alcoholic hepatitis is reversible and forms over what time scale?
4-6 weeks
What is the differential diagnosis for steatosis?
Alcoholic hepatisis NASH, Diebetes type 2 Drugs Pregnancy Nutritional (TPN) Hepatitis C