ASCITES CAUSES

The two most important factors in the production of ascites due to chronic liver disease are:

Low levels of albumin in the blood that cause a change in the pressure necessary to prevent fluid exchange (osmotic pressure). This change in pressure allows fluid to seep out of the blood vessels.
An increase in the pressure within the branches of the portal vein that run through liver (portal hypertension). Portal hypertension is caused by the scarring that occurs in cirrhosis. Blood that cannot flow through the liver because of the increased pressure leaks into the abdomen and causes ascites.

Other conditions that contribute to ascites development include:

Hepatitis
Heart or kidney failure
Inflammation and fibrous hardening of the sac that contains the heart (constrictive pericarditis).

Persons who have systemic lupus erythematosus but do not have liver disease or portal hypertension occasionally develop ascites. Depressed thyroid activity sometimes causes pronounced ascites, but inflammation of the pancreas (pancreatitis) rarely causes significant accumulations of fluid.