Ascites (Fluid in the Abdomen)

What is ascites?

Ascites is a collection of more fluid than normal in the abdominal cavity. In everyday speech it is sometimes called “water gathering in the abdomen”.

Ascites is not a disease in itself. It is generally a sign arising as a result of another disease. The commonest cause is advanced liver disease and cirrhosis, but heart disease, certain cancers, kidney disease and, less often, infections or diseases of the pancreas can also lead to ascites.

Swelling of the abdomen that is new or increasing rapidly must be assessed.

Why does ascites form?

In cirrhosis, the structural changes that develop in the liver make it harder for blood to flow through it, and cause the rise in pressure called portal hypertension.

At the same time, mechanisms that make the body retain salt and water come into play. Fluid may then leave the blood vessels and begin to collect in the abdominal cavity.

Put simply:

liver disease → a rise in portal vein pressure → retention of salt and water by the kidneys → fluid collecting in the abdominal cavity → ascites

What are the commonest causes of ascites?

One of the commonest causes of ascites is cirrhosis of the liver.

Besides that, ascites can be caused by:

• Heart failure,
• Certain cancers affecting the lining of the abdomen or the organs within it,
• Kidney disease,
• Certain infections such as tuberculosis,
• Diseases of the pancreas,
• Obstruction of certain blood vessels in the liver and the abdomen.

For this reason, when ascites is found, what matters is not only draining the fluid but establishing why it formed.

What symptoms does ascites cause?

When the amount of fluid is small the patient may feel no symptoms at all.

As the fluid increases there may be:

• Swelling and tightness of the abdomen,
• A progressive increase in the girth of the abdomen,
• Weight gain,
• Feeling full early,
• Loss of appetite,
• Shortness of breath,
• Difficulty moving about,
• Swelling of the feet and legs,
• A feeling of heaviness or discomfort in the abdomen.

When a large amount of ascites forms, the abdomen can become quite tight and press on the diaphragm, making breathing difficult.

How is ascites diagnosed?

The doctor may suspect fluid in the abdomen during the examination.

One of the methods used most often in making the diagnosis is ultrasound of the abdomen. Ultrasound can show even an amount of fluid too small to be noticed on physical examination.

Depending on the patient’s situation, the following may be used:

• Liver tests,
• Kidney function,
• Sodium and potassium,
• Albumin,
• INR,
• A full blood count,
• Ultrasound of the abdomen,
• Doppler ultrasound,
• Computed tomography or other imaging methods where needed.

But in ascites appearing for the first time in particular, examining the fluid itself is very valuable.

What is paracentesis?

Paracentesis is the taking of a sample of fluid from the abdominal cavity, or the draining of excess fluid, with a fine needle or catheter.

It can be done for two different purposes.

Diagnostic paracentesis

A small amount of fluid is taken and examined in the laboratory.

This examination can give information about:

• Whether the ascites is due to liver disease,
• Whether there is infection in the fluid,
• Whether certain cancers or other conditions are involved.

Therapeutic paracentesis

Where there is a great deal of ascites and it is causing tightness of the abdomen, pain or shortness of breath, a larger amount of fluid can be drained.

In most patients this can quickly reduce the tightness of the abdomen and the shortness of breath.

What tests are done on the ascitic fluid?

Depending on the patient’s situation, the fluid taken may be tested for:

• A cell count,
• Albumin,
• Protein,
• Culture,
• Cytological examination and other specific tests where needed.

Comparing the albumin values in the blood and in the ascitic fluid allows a value called the SAAG (serum-ascites albumin gradient) to be calculated.

SAAG helps the doctor establish whether the ascites is due to portal hypertension.

These are not assessments for the patient to interpret themselves; the results are assessed together with the other clinical and laboratory findings.

Can the ascitic fluid become infected?

Yes.

In patients with cirrhosis in particular, infection can develop in the ascitic fluid without any other clear focus of infection in the abdomen. This is called spontaneous bacterial peritonitis (SBP).

This can be serious and requires prompt treatment.

In a patient with ascites, a healthcare provider should be seen without delay if there develops:

• Fever,
• Newly begun abdominal pain,
• Tenderness of the abdomen,
• Confusion or a tendency to sleep,
• A sudden deterioration in general condition,
• Low blood pressure,
• Worsening of kidney function.

Importantly, in some patients the infection can develop without fever or marked abdominal pain.

How is ascites treated?

Treatment is planned first of all according to the cause of the ascites.

In ascites due to cirrhosis, the aim of treatment is both to reduce the fluid in the abdomen and to prevent it collecting again as far as possible.

1. Reducing salt

In ascites due to cirrhosis, the body’s retention of excess salt is one of the main reasons for the fluid collecting.

Patients are therefore generally advised to keep their daily sodium intake below about 2 grams. That amount corresponds to roughly 5 grams of table salt.

But excessive and unsupervised restriction of salt reduces the taste of food and can lead to inadequate nutrition, particularly in patients with advanced liver disease.

The diet should therefore be arranged for the individual.

2. Water tablets (diuretics)

Diuretics such as spironolactone and furosemide are often used in the treatment of ascites.

These medicines help the excess salt and water in the body to be passed in the urine.

But the doses have to be adjusted under a doctor’s supervision. Using too much diuretic can cause problems such as:

• Deterioration of kidney function,
• A low sodium level,
• Disturbances of potassium,
• Low blood pressure,
• Dehydration.

Blood tests and body weight may therefore need to be monitored during treatment.

Does water need to be restricted too?

Not every patient with ascites needs to restrict water.

In ascites due to cirrhosis the basic approach is reducing salt. Fluid restriction is advised by the doctor mostly in patients whose blood sodium has fallen markedly.

For this reason it is not right for a patient to restrict water severely on their own.

What is done if there is a great deal of ascites?

If the abdomen is very tight and the patient is having difficulty breathing or eating, fluid can be drained by large-volume paracentesis.

When a large amount of ascitic fluid is drained, some patients need albumin to be given intravenously in order to protect the circulation and kidney function.

Paracentesis can reduce ascites quickly, but because it does not remove the underlying disease the fluid can collect again over time.

What is resistant (refractory) ascites?

Where the ascites cannot be brought under control despite salt restriction and an appropriate, tolerated dose of diuretic treatment, or where the fluid collects again shortly after paracentesis, this is called resistant or refractory ascites.

This is one of the important markers that the liver disease has reached an advanced stage.

In these patients the following may come into consideration:

• Repeated paracentesis,
• Giving albumin,
• TIPS in suitable patients,
• Assessment for liver transplantation.

What is TIPS?

TIPS (transjugular intrahepatic portosystemic shunt) is a special connection between blood vessels, created by interventional radiology, in order to reduce the high portal vein pressure within the liver.

In suitably selected patients it can help bring refractory ascites under control and can reduce the need for paracentesis.

But TIPS is not suitable for every patient. Many factors are assessed together — liver function, the state of the heart, age, kidney function, and the risk of hepatic encephalopathy.

Why does the development of ascites matter?

In a patient with cirrhosis, the development of ascites is one of the important markers that the disease has entered its decompensated stage.

For this reason ascites should not be seen merely as an uncomfortable collection of fluid in the abdomen.

The patient’s:

• Cause of liver disease,
• Liver function,
• Kidney function,
• Nutritional state,
• Risk of infection,
• Screening for liver cancer,
• Suitability for liver transplantation where needed

should all be assessed as a whole.

What should a patient with ascites attend to?

• The salt restriction the doctor advises should be followed.
• The dose of diuretics should not be changed on one’s own.
• Regular monitoring of weight can be useful.
• Alcohol should not be taken.
• Herbal products or supplements should not be taken without consulting the doctor.
• Because certain painkillers such as ibuprofen, diclofenac and naproxen can impair kidney function, they should not be taken without consulting a doctor, particularly by people with cirrhosis and ascites.
• Protein should not be cut out entirely. It matters that patients with liver disease take enough protein and calories.
• Regular check-ups should not be missed.

When should a doctor be seen urgently?

In a patient with ascites, medical assessment is needed without delay if there develops:

• Fever,
• Newly begun or increasing abdominal pain,
• A change in consciousness or excessive sleepiness,
• Vomiting blood,
• Black stools,
• A marked reduction in the amount of urine,
• Severe shortness of breath,
• Rapidly increasing swelling of the abdomen,
• Low blood pressure or fainting.

The important message

Ascites is not a disease but a sign of an underlying one.

Although the commonest cause is cirrhosis of the liver, not every ascites has the same cause. In newly developed ascites in particular, establishing the cause and, where needed, taking a sample of the ascitic fluid, matters.

Ascites due to cirrhosis can be brought under control with appropriate nutrition and salt restriction, diuretics, paracentesis where needed and, in selected patients, TIPS.

But because the development of ascites can be an important marker of advanced liver disease, what needs to be assessed and followed regularly is not only the fluid in the abdomen but the liver disease as a whole.

This content has been prepared for general information. Because the cause and the treatment of ascites can vary from person to person, decisions on diagnosis and treatment should be made by a doctor.