Block 15 Flashcards
(81 cards)
Definition of Cirrhosis
chronic damage → hepatocyte destruction → chronic scarring + damage tht become irreversible → liver becomes fibrotic
Which cells mediate the fibrosis process?
Stellate cells
Where are stellate cells found?
in the perisinusoidal space btwn. hepatocytes + sinusoid
Main function of stellate cells
store vitamin A
What do injured hepatocytes release that activate stellate cells?
parakrin factors
What happens to activated stellate cells?
- they lose vitamin A
- they proliferate
- they secrete TGF-beta
all of this triggers collagen production => fibrotic tissue formation
Explain the mechanism of portal hypertension
build up of fibrotic tissue compresses central vein + sinusoids → increases P in sinusoid and thus the portal veins
OR
new vessels produced in angiogenesis provide low-volume, high P venous drainage tht cannot accomodate as much blood vol as normal => portal vein P increases
Why does portal hypertension increase risk of ascites + congestive splenomegaly?
increased chance tht fluid in BVs gets pushed into tissues + across tissues into lrg open spaces e.g. peritoneal activity –> ascites
Pathological effects of decreased liver function
- ⇒ decreased detoxification ⇒ toxins can enter brain and cause hepatic encephalopathy e.g. ammonia → asterixis(hand tremor)
- decreased oestrogen metabolism ⇒ more oestrogen in blood → gynaecomastia, spider angiomata, palmar erythema
- increased unconjugated bilirubin as liver normally conjugates bilirubin ⇒ jaundice
- decreased albumin → hypoabluminaemia
- decreased clotting factor production- prolongs prothrombin time
Describe some histopathological features of cirrhosis:
- regenerating nodules
- bridging fibrosis
Why does transaminase increase in hepatitis?
damaged hepatocytes leak out amino transminase into blood which increases liver transaminase => ALT + AST will increase
Describe the general mechanism of hepatitis infection
Hep virus infects hepatocyte → CD8+ cells recognise abnormal proteins presented on MHC I → Cytotoxic killing → hepatocyte apoptosis → liver damage → increased transaminase
What are then signs + symptoms of the icteric phase of acute viral hepatitis?
- darkened urine -> conjugated bilirubin gets filtered into urine making it darker
Jaundice
Anticteric hepatitis is
hepatitis w/o jaundice
3 types of jaundice
Pre-hepatic
Intrahepatic
Post-hepatic
Pre-hepatic jaunduce
- excessive RBC breakdown
- overwhelms liver’s ability to conjugate bilirubin ⇒ unconjuagted hyperbilirubinaemia
Causes of Intrahepatic Jaundice
hepatic cell dysfunction ==> liver loses ability to conjugate bilirubin
Causes of post-hepatic jaundice
biliary drainage obstruction
e.g. gallstones, abdo masses
Definition of Jaundice
high levels of bilirubin in blood
Most common causes of jaundice
- viral hepatitis
- alcohol related liver disease
Types of hepatitis transmitted by faecal-oral route
Hep A and Hep E
Type of hepatitis transmitted by blood
Hep C and Hep B
Key marker of Hep B
HBV surface antigen HbsAg
Which Hep virus needs Hep B to infect?
Hep D