Lecture 17: Liver Pathology Flashcards
What is the normal weight of the liver?
1400-1600 grams
What is the porta hepatis?
- Portal vein
- Hepatic artery
- BIle duct
What are the anatomical divisions of the liver?
Lobules
What are the functional divisions of the liver?
Acini
Describe the normal liver architecture?
Portal tract;
- Hepatic art.
- Bile duct
- Portal vein
Parenchyma
- Zone 1 (periportal)
- Zone 2 (Mid-zonal)
- Zone 3 (Centrilobular)
Terminal hepatic vein
What are two common patterns of liver disease?
- Cirrhosis
- Portal hypertension
Both potential consequences of liver pathology.
Describe how liver cirrhosis results;
End stage liver damage
- Death and atrophy
- Inflammation leads to fibrosis = cirrhosis, loss of synthetic function (Hep. damage) (No normal flow from liver to portal vein)
Different sized nodules depending on eitiology.
Describe the change of liver architecture in liver cirrhosis;
- Bridging fibrous septae (Link portal tracts)
- Parenchymal nodules (Proliferating hepatocytes encircled by fibrosis, Micro and macro nodules)
Disruption of entire architecture
- Vascular architecture reorganised with shunts; PV and HA blood bypasses functional liver cells
- Progressive fibrosis
What is portal hypertension and what causes it?
- Increased resistance to portal blood flow
- Prehapatic (obstructive thrombosis)
- Posthepatic (Severe R. sided heart failure)
- Intra hepatic (Cirrhosis)
What is the consequences of portal hypertension?
- Ascites
- Portosystemic shunts; Bypasses develop where systemic and portal circulation share capillary bed.
- Congestive splenomegaly
- Hepatic encephalopathy (Diffuse confusion)
What can cause viral hepatitis?
- Hepatitis A, B, C, D and E virus
- Cytomegalovirus
- Epstein-barr virus
What are some notes on Hepatitis A virus;
- Benign self-limited disease
- Incubation, 2-6 weeks
- Does not cause chronic hepatitis
- Substandard hygiene and sanitation
- Person to person, feacal oral transmission
- Asymptomatic or mild febrile illness +/- jaundice
What are some notes on hepatitis B virus;
- Acute (resolves) or chronic which may lead to cirrhosis
- Fulminant hepatitis leads to massive necrosis
- Associated with hepatitis D infection
- 4-26 weeks infection
- Blood and body fluid born
- Immune response to viral antigens expressed on infected hepatocytes leads to liver cell damage
What are some notes on hepatitis C virus;
- Major cause of liver disease
- Inoculations and blood transfusions
- Acute infection usually undetected
- Chronic disease usually occurs in majority
- 20+% develop cirrhosis 5-20 years post infection
How are drug and toxin induced liver injury classified?
- Predictable hepatotoxins (acting in dose dependant manner and occurring in most individuals) i.e paracetamol
- Unpredictable/idiosyncratic hepatotoxins
How can hepatotoxins act?
- Directly through cell toxicity, act through hepatic conversion to an active toxin or active immune mechanisms.
What is the pattern of injury for hepatotoxins?
Pattern of injury includes;
- Cholestasis
- Hepatotcellular necrosis
- Fatty liver disease
- Fibrosis
- Granulomas
- Vascular lesions and neoplasms.
What is the most common thing to cause acute liver failure?
Paracetamol
What is the most common thing to cause chronic liver failure?
Alcohol
What is found in alcoholic fatty liver disease?
- Hepatic steatosis (Fatty change)
- Alcoholic hepatitis
- Cirrhosis
What are the pathological effects of alcohol?
- Changed lipid metabolism
- Decreased export of lipoproteins
- ROS induced cell injury and cytokines
What is non alcoholic fatty liver disease associated with?
- Metabolic syndrome
- Obesity
- T2D
- Dyslipidemia (hypercholestremia)
- Hypertension
What is the spectrum of disease activity for NAFLD?
- Initially hepatic steatosis
- May progress to steatosis and inflammation (NASH: non-alcoholic steatohepatisis)
- Over 15 years, 11% patient with NASH progress to cirrhosis.
What is heamochromatosis?
- Excessive accumulation of body iron in the liver and pancreas.
