What is the pathophysiology of portal hypertension?
Portal hypertension is characterized by a pathologic increase in portal venous pressure that leads to the formation of an extensive network of portosystemic collaterals that divert a large fraction of portal blood to the systemic circulation, bypassing the liver.
What is the pathophysiologic relationship between cirrhosis and portal hypertension?
The most common cause of portal hypertension is cirrhosis, or scarring of the liver. Cirrhosis results from the healing of a liver injury caused by hepatitis, alcohol abuse or other causes of liver damage. In cirrhosis, the scar tissue blocks the flow of blood through the liver and slows its processing functions.
What is the pathophysiology of cirrhosis?
Cirrhosis slows the normal flow of blood through the liver, thus increasing pressure in the vein that brings blood to the liver from the intestines and spleen. Swelling in the legs and abdomen. The increased pressure in the portal vein can cause fluid to accumulate in the legs (edema) and in the abdomen (ascites).
What are the three categories of portal hypertension?
With regard to the liver itself, causes of portal hypertension usually are classified as prehepatic, intrahepatic, and posthepatic.
What happens portal hypertension?
Portal hypertension occurs when there is an obstruction of blood flow through the liver, and pressure rises within the portal vein. This obstruction can be intrahepatic (intra=within +hepatic=liver), pre-hepatic (pre=before) or post- hepatic (post=after).
Does portal hypertension cause hypertension?
Portal hypertension is a detrimental complication resulting from obstruction of portal blood flow, such as cirrhosis or portal vein thrombosis. In liver cirrhosis, increased intrahepatic vascular resistance to the portal flow elevates portal pressure and leads to portal hypertension (Figure 1).
Why does splenomegaly occur in cirrhosis?
Liver disease such as cirrhosis, or liver scarring, can cause the blockage of blood flow through the liver, thus causing blood to back up in the portal vein resulting in increased pressure or portal hypertension. As a result, the spleen becomes engorged with blood, leading to splenomegaly.
What is the relationship between cirrhosis and portal hypertension?
Portal hypertension, defined as an increase in pressure gradient between the portal venous system and the hepatic veins, is a major consequence of the progression of chronic liver disease, because it gives rise to most of the complications that lead to death or to listing for liver transplantation in patients with cirrhosis.
Which is the most common cause of portal hypertension?
Figure 4. Suprahepatic causes of portal hypertension. Hepatic Causes Cirrhosis is the most common cause of portal hypertension, and chronic viral hepatitis C is the most common cause of cirrhosis in the United States. Alcohol-induced liver disease and cholestatic liver diseases are other common causes of cirrhosis.
What causes increased intrahepatic vascular resistance in cirrhosis?
In cirrhosis, increased intrahepatic vascular resistance is a result of massive structural changes associated with fibrosis/cirrhosis and intrahepatic vasoconstriction2-4. It is reported that intrahepatic vasoconstriction accounts for at least 25% of increased intrahepatic vascular resistance.
How does portal hypertension affect the gut and liver?
Increased portal pressure caused by portal hypertension may influence the gut–liver axis, further advance the pathology of liver fibrosis/cirrhosis, and exacerbate portal hypertension itself. Therefore, gut microflora may have an important role in a pathological loop that develops and maintains portal hypertension.