Cirrhosis pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Aditya Govindavarjhulla, M.B.B.S. [2]
Overview
Pathophysiology
The liver plays a vital role in synthesis of proteins (e.g. albumin, clotting factors andcomplement), detoxification and storage (e.g. vitamin A). In addition, it participates in the metabolism oflipids and carbohydrates.
Cirrhosis is often preceded by hepatitis and fatty liver (steatosis), independent of the cause. If the cause is removed at this stage, the changes are still fully reversible.
The pathological hallmark of cirrhosis is the development of scar tissue that replaces normal parenchyma, blocking the portal flow of blood through the organ and disturbing normal function. Recent research shows the pivotal role of stellate cell, a cell type that normally stores vitamin A, in the development of cirrhosis. Damage to the hepatic parenchyma leads to activation of the stellate cell, which becomes contractile (called myofibroblast) and obstructs blood flow in the circulation. In addition, it secretes TGF-β1, which leads to a fibrotic response and proliferation of connective tissue. Furthermore, it disturbs the balance between matrix metalloproteinases and the naturally occurring inhibitors (TIMP 1 and 2), leading tomatrix breakdown and replacement by connective tissue-secreted matrix.[1]
The fibrous tissue bands (septa) separate hepatocyte nodules, which eventually replace the entire liver architecture, leading to decreased blood flow throughout. The spleen becomes congested, which leads to hypersplenism and increased sequestration ofplatelets. Portal hypertension is responsible for most severe complications of cirrhosis.
References