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About fluid in the abdomen

This page tells you about fluid in the abdomen (ascites). There is information on


What ascites is

Ascites (pronounced ay-site-eez) is the medical name for a build up of fluid in the abdomen. The abdomen is the area of the body below the ribs and lungs and above the hip bones. It contains many of the body's organs, including the stomach, small and large bowel, pancreas, liver, spleen, and kidneys.

Around the organs of the abdomen there is a sheet of tissue called the peritoneum. It is made up of 2 layers. One layer of the peritoneum lines the wall of the abdomen. The other layer covers the organs in the abdomen.  The layers produce a small amount of fluid, so that the organs in the abdomen can move smoothly.

Sometimes fluid builds up between the 2 layers of the peritoneum. This makes the abdomen swell.



The causes of ascites in the abdomen

There are a number of possible causes of fluid in the abdomen (ascites).  It may develop when

  • Cancer cells irritate the lining of the abdomen and make it produce too much fluid
  • The lymph glands in the abdomen become blocked so that they can’t drain fluid out of the abdomen as they usually do
  • Areas of cancer in the liver raise the pressure in nearby blood vessels, forcing fluid out of the blood vessels and into the abdominal cavity
  • The liver is not working normally – it can’t make blood proteins as it should, causing fluid to leak out of the veins and into the abdominal cavity
  • The heart is not working normally

A number of conditions can cause fluid in the abdomen, including liver disease, heart disease and cancer. This page is about ascites due to cancer. This is usually a sign that the cancer has spread and is advanced. Cancers that can cause ascites include  


Symptoms of ascites

The main symptom of fluid in the abdomen is swelling. This often develops over a few weeks but may happen over a few days. Symptoms include

  • Clothes feeling tighter, or needing to increase your belt size
  • Bloating
  • Feeling uncomfortable
  • Abdominal pain
  • Back pain
  • Difficulty sitting comfortably and moving about
  • Feeling sick
  • Loss of appetite
  • Indigestion
  • Constipation
  • Needing to pass urine often
  • Shortness of breath
  • Tiredness (fatigue)

Tests for ascites

Your doctor will examine you and ask you about your symptoms. You will have tests to help find out what is causing the fluid build up in your abdomen. These may include

  • An ultrasound scan
  • Sampling the fluid from your abdomen to check for cancer cells and infection
  • Blood tests to check your general health and how well your liver and kidneys are working
  • A CT scan

To take a sample of fluid, your hospital doctor puts a needle into your abdomen using an ultrasound scan to guide them. They use a syringe to draw out some fluid and send it to the laboratory to be examined under a microscope. In the lab, they will look for cancer cells in the fluid.

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Updated: 15 September 2015