Pathology: Liver

Question 1

Causes of Liver Injury

Answer 1

• Alcohol
• Drugs and toxins
• Infection
• Autoimmune disorders
• Metabolic
• Genetic

Question 2

Cirrhosis

Answer 2

• End stage liver disease
• Irreversible
• Usually takes years to develop
• Diffuse hepatic fibrosis and scar tissue - caused by chronic inflammation of liver - permanent alteration of liver blood flow and function

Question 3

Cirrhosis: Causes

Answer 3

• Alcoholic liver disease
• Viral hepatitis
• Cryptogenic cirrhosis (metabolic syndrome)
• Biliary cirrhosis (inflammation/blockage of bile ducts)
• Genetic
• Drugs
• Autoimmune conditions

Question 4

Cirrhosis: Therapy

Answer 4

• Main supportive therapy: improve nutrition, correct vitamin deficiencies
• Patients with end-stage liver disease are potential candidates for liver transplant

Question 5

Cirrhosis: Morphology

Answer 5

• Lobules replace by bridging fibrous septa (walls)
• Delicate bands or broad scars of collagenous tissue
• Small to large nodules of regenerating heptocytes
• Distribution of the architecture of the entire liver

Question 6

Cirrhosis: Mechanism

Answer 6

Repeated injury to hepatocytes causes:

1. Progressive hepatocyte injury and death + chronic inflammation: release of toxins and cell signalling molecules from liver cells and inflammatory cells
2. Cytokines and toxins activate stellate cells (usually just Vit A storage)
3. Stellate cells transform to myofibroblasts and synthesise fibrous bands of enw EXM rixh in collagen I and III (process called fibrosis) -> causes disruption of normal ECM
4. Converts sinusoids from slow flow channels allowing exchange of nutrients and toxins, into fast flow channels without exchange
5. Cytokines also cause proliferation of remaining hepatocytes to form nodules between the fibrous bands

Question 7

Cirrhosis: Clinical Features

Answer 7

• Jaundice
• Ascites
• Muscle weakness, anorexia and malnutrition
• Portal hypertension

Question 8

Ascites

Answer 8

• Build up of fluid in peritoneal cavity
• Linked to late stage cirrhosis and portal hypertension
  Caused by:
• Raised hydrostatic pressure in the portal vein system leading to increased extravascular fluid which drains into the peritoneum
• Hypoalbuminemia: low blood protein production by liver reduces osmotic pressure of the blood so less extravascular fluid flows back into the blood