Ascites is the accumulation of protein-containing (ascitic) fluid within the abdomen.
Ascites tends to occur in long-standing (chronic) rather than in short-lived (acute) disorders. It occurs most commonly in cirrhosis (severe scarring of the liver), which is commonly caused by consumption of large amounts of alcohol or by viral hepatitis. Ascites may occur in other liver disorders, such as severe alcoholic hepatitis without cirrhosis, chronic hepatitis, and obstruction of the hepatic vein (Budd-Chiari syndrome). Ascites can also occur in disorders unrelated to the liver, such as cancer, heart failure, kidney failure, inflammation of the pancreas (pancreatitis), and tuberculosis affecting the lining of the abdomen.
In people with a liver disorder, ascitic fluid leaks from the surface of the liver and intestine and accumulates within the abdomen. A combination of factors is responsible. They include portal hypertension (high blood pressure in the veins that bring blood from the intestine to the liver), fluid retention by the kidneys, and alterations in various hormones and chemicals that regulate body fluids. Also, blood vessels become less able to retain fluid because albumin is usually also lost from the blood into fluids in the abdomen. Albumin, the main protein in blood, helps keep fluid from leaking out of blood vessels
Occasionally, an infection called spontaneous bacterial peritonitis develops in ascitic fluid for no apparent reason. Untreated, this infection can be fatal. Survival depends on early treatment with appropriate antibiotics.
Small amounts of fluid within the abdomen usually cause no symptoms, but massive amounts may cause abdominal swelling (distention) and discomfort. The swollen abdomen puts pressure on the stomach, sometimes leading to loss of appetite, and pressure on the lungs, sometimes leading to shortness of breath.When a doctor taps (percusses) the abdomen, the fluid makes a dull sound. When the abdomen contains large amounts of fluid, the abdomen is taut, and the navel is flat or even pushed out. In some people with ascites, the ankles swell because excess fluid accumulates there (causing edema).
When a doctor taps (percusses) the abdomen, the fluid makes a dull sound. However, a doctor may not be able to detect ascitic fluid unless the volume is about a quart or more.
If doctors are uncertain whether ascites is present or what is causing it, they may do ultrasonography.In addition, a small sample of ascitic fluid can be withdrawn by inserting a needle through the wall of the abdomen—a procedure called diagnostic paracentesis (see Paracentesis). Laboratory analysis of the fluid can help determine the cause.
The basic treatment for ascites is a low-sodium diet, usually combined with drugs called diuretics. Diuretics make the kidneys excrete more sodium and water into the urine.
If ascites makes breathing or eating difficult, the fluid may be removed through a needle inserted into the abdomen—a procedure called therapeutic paracentesis. The fluid tends to reaccumulate unless people also follow a low-sodium diet and take a diuretic. Because a large amount of albumin is usually lost from the blood into the abdominal fluid, albumin may be given intravenously.
If large amounts of fluid accumulate frequently or if other treatments are ineffective, a portosystemic shunt or liver transplantation may be needed. The portosystemic shunt connects the portal vein or one of its branches with a vein in the general circulation and thus bypasses the liver (see Treatment).
Last full review/revision August 2012 by Steven K. Herrine, MD