HOW LIVER CIRRHOSIS OCCUR, TYPES AND CAUSES
Cirrhosis is the disease which mainly affects the liver. In cirrhosis condition liver does not work properly due to long term damage of liver.
Introduction to liver :-
Liver is the largest organ in the body weighing 1400-1600 grams in males and 1200-1400 grams in females.
Liver consists of two main lobes:-
- Right lobe.
- Left lobe .
- Liver plays a major role in detoxification of toxic substances.
- Mainly important for metabolism.
- The liver cells are called hepatocytes, any of the abnormalities caused destruction of hepatocytes which leads to various liver diseases.
Liver disorders :-
The damage of liver may shows many of the diseases like :-
- Hepatic failure
Cirrhosis of the liver is one of the 10 leading causes of deaths, it represents the irreversible and stage of several diffuse diseases causing hepatocellular injury
It can be characterized by four features :-
- It involves entire liver.
- The normal structure of liver is disorganized.
- Formation of nodules and separated from one another by irregular bands of fibrosis.
- It occurs due to hepatocellular necrosis & regenerative nodules.
Pathogenesis of LIVER CIRRHOSIS :-
It involves combination of few processes :-
- Hepatocellular necrosis
- Healing of fibrosis
- Formation of compensatory regenerative nodules.
It occurs mainly by the three methods :-
Continued destruction of hepatocytes
Cause collapse of normal globular hepatic parenchyma
Leads to fibrosis
Increased synthesis of type 1 and type 3 collagen.
Proliferation of fat strong cells in to myofibroblasts and fibrocytes.
Two glycoproteins fibronectin and laminin are deposited in excessive amount in area of liver
Liver cells damage .
Regenerative nodules :-
Acts as stimulants for growth and proliferation of more hepatocytes.
Proliferation of hepatocytes is restricted within fibrous nodules.
Forming degenerative nodules .
Due to damaged parenchyma of liver
Formation of fibrous nodules.
New vessels formed in the septa are connected to a vessel in a portal triad.
Blood is drained in to hepatic vein .
Thus blood bypasses the hepatic parenchyma
Gaps in the hepatic sinusoidal are closed
Results in development of capillaries in the sinusoidal.
Classification of LIVer cirrhosis :-
Based on etiology and also morphology.
- Morphological classification:-
These are 3 types.
- Micronodular cirrhosis: In this type nodules are usually regular and small less than 3mm in diameter. It represents impaired capacity for regrowth as seen in alcoholism, malnutrition, severe anaemia.
- Macronodular cirrhosis : In this type nodules are variable size larger than 3mm in diameter , or is more irregular than micronodular cirrhosis.
- Mixed cirrhosis: In this type some parts of liver shows micronodular appearance and other parts shows macronodular.
Based on etiology :-
- Alcoholic liver disease and cirrhosis :-
This term is used to describe the spectrum of liver injury associated with acute and chronic alcoholism.
These are 3 stages in alcohol liver disease :-
Stage.1 :- Alchoholsteatosis (fatty liver )
Stage.2 :- alchoholic hepatitis.
Stage.3 :- alchoholic cirrhosis
Ethanol metabolism :-
- One gram of alcohol gives 7 calories but it is not stored in the body and undergoes oxidation in the liver thus no contribution to nutrition other than to give energy.
- Ethanol after ingestion and absorption from small bowel circulates through liver.
- Where about 90% is oxidized to acetate by a 2 step enzymatic process and the enzymes involved are :-
- Alcohol dehydrogenase (in cytosol)
- Acetaldehyde dehydrogenase ( in mitochondria).
Metabolism of ethanol in liver :-
The Acetate converted into Acetyl-coA, This acetyl coA converted into carbon dioxide and water.
Risk factors for alcoholic liver diseases :-
Some Individuals are predisposed to alcoholic cirrhosis is not clearly known but few risk factors are :-
- Drinking patterns :-
- Epidemiological studies have attributed alcoholic cirrhosis to chronic alcoholism.
- Excessive consumption of alcoholic leads to fatty liver.
- Gender :-
- Women have increased acceptability.
- Develop advanced alcoholic liver disease.
- Absolute malnutrition of proteins and vitamins is regarded as a contributory factor in the evolution of cirrhosis.
- Inter current bacterial infections are common in cirrhosis patient’s and may accelerate the cause of disease.
- Genetic factors :-
- The rate of ethanol metabolism in under genetic control
- The two genetic enzymes are :-
- MEOS (microsomal p450 oxidase )
- Alchohol dehydrogenase.
6. Hepatitis B and C infection:-
- Concurrent infection with either HBV or HCV is an iimportant risk factor for progression of alchoholic liver disease .
Causes of liver cirrhosis:-
- Viral hepatitis
- Chemical hepatotoxins.
- Other infections example- parasitic infections & Wilson disease
- Idiopathic cause
- Excessive consumption of alcohol
- Decreased enzymes in the liver.
- Destruction of hepatocytes.
Laboratory diagnosis :-
- Liver biopsy – study of liver called liver biopsy.
- The progressive form of the disease however generally presents following biochemical and hematological alterations Such as
- Elevated transaminases -increased SGOT is more than that of SGPT.
- Rise in serum gamma glutamic transpeptidase.
- Elevation of serum alkaline phosphatase
Symptoms of Liver cirrhosis:-
- Hyperbilurubinaemia may leads to jaundice
- Destruction of blood cells (RBC) &(WBC)
- Decreased blood clotting time .
Thanks for reading………
PRAVEENA, LATHA SREE
References :- – 1. Harsh mohan, text book of pathology, latest edition.
2. Tripathi, Essentials of Medical Pharmacology.