Histopath 8: Liver Pathology Flashcards
What direct does blood and bile flow in the liver?
Blood = Zone 1 -\> zone 3 Blie = zone 3 -\> zone 1
What are the 3 different zones of a liver lobule known as
Z1 - Periportal - closest to portal triad
Z2 - Mid Zone
Z3 - Periventricular - most mature hepatocytes (least oxygenated - most sensitive to ischaemia)
What part of the liver lobule is most likely to be affected by:
- Viral hepatitis and toxic substance ingestion
- Metabolic toxins
Viral hepatitis and toxic substance ingestion:
Periportal / Z1 (closest to portal triad)
Metabolic toxins (ethanol, paracetamol): Perventricular / Z3 = Most liver enzymes: most sensitive to metabolic toxins (ethanol, paracetamol)
NB - alcohol isnt toxic however Z3 has the most alcohol dehydrogenase hence makes a lot of acetaldehyde which is the issue
What is acute hepatitis caused by?
Viral (Hep A-E)
Drugs
Histopathological features of acute hepatitis?
Spotty necrosis - Small foci of inflammation and necrosis with inflammatory infiltrates
This usually concentrates around portal triad + smaller v what is seen in chronic hep
What is chronic hepatitis caused by?
Viral (Not Hep A or E)
Drugs
PBC, PSC, Wilson, hemochromatosis
Histopathological features of chronic hepatitis?
Piecemeal necrosis/interface hepatitis
- Loss of the border between the portal tract and the surrounding parenchyma (lot more widespread compared to spotty necrosis)
Bridging fibrosis from portal triad → central vein: Signals evolution to cirrhosis (this means blood cant come into close contact w/ liver enzymes)
What is cirrhosis?
Abnormality of liver architecture – interferes with liver function and blood flow
What are the key features of cirrhosis?
Hepatocyte necrosis
Nodules of regenerating hepatocytes
- Micronodular: alcoholic hepatitis
- Macronodular: alpha-1, Wilson’s, viral hepatitis
Distortion of vascular architecture
Fibrosis
Difference between extra- and intra-hepatic shunting as seen in cirrhosis?
Extrahepatic shunting – Blood backlogs into the sites of porto-systemic anastomosis -> Esophageal varices, anorectal varices, caput medusae
Intrahepatic shunting – Blood goes through liver but does not contact hepatocytes/is not filtered
Complications of liver cirrhosis?
Portal hypertension
Hepatic encephalopathy
Hepatocellular carcinoma
What are the 3 main histological pattens of alcoholic liver disease?
Hepatic steatosis
Alcoholic hepatitis
Alcoholic cirrhosis
IMPORTANT TO REMEMBER THESE CAN CO-EXIST
What are the main features of Hepatic steatosis?
Fully reversible if alcohol is avoided
Large, pale, yellow greasy liver
Buzz words:
- Fat droplets in hepatocytes
What are the main features of Alcoholic hepatitis?
Large, fibrotic liver
80% also cirrhotic
Buzzwords:
- Hepatocyte ballooning (when hepatocytes die due to alcohol)
- Mallory Denk Bodies (bits of hyaline - stains blue)
- Mainly zone 3 damage (most metabolic active site)
- Neutrophil polymorphs
- Fibrosis
What are the main features of Alcoholic cirrhosis?
Shrunken brown organ
Buzzwords:
- Micronodular cirrhosis
What are the main features of NAFLD? Cause?
Histologically similar to alcoholic liver disease (ballooning, mallory denk etc)
Distinguished based on history
Cause: insulin resistance associated with raised BMI and diabetes