Peritoneal effusion, also called ascites, is a buildup of extra fluid in the lining of the belly. It may be described as abdominal swelling. A few types of cancer can cause abdominal effusion, including peritoneal mesothelioma. Doctors may recommend draining the fluid to help control this symptom.

01. Overview

What Is Peritoneal Effusion?

Peritoneal effusion, or ascites (uh-sai-teez), is a collection of fluid in the lining of the lower abdomen (peritoneum). With ascites, an abnormal amount of fluid builds up between the two layers of the peritoneum. This fluid can put pressure on abdominal organs, potentially causing pain, swelling and other symptoms.

Treatment may vary depending on the ascites severity and cause. Often, the cause is cirrhosis of the liver or cancer. If cancer is the cause, it is considered malignant peritoneal effusion. This diagnosis has related treatment options to help reduce fluid buildup and prevent it from recurring.

Other Names for Peritoneal Effusion

Doctors may use other terms or phrases to reference peritoneal effusions, including:

  • Abdominal effusion
  • Ascites
  • Buildup of free fluid in the abdomen
  • Excess peritoneal fluid
  • Extra fluid in the peritoneum
  • Fluid buildup in the peritoneal cavity
  • Intraperitoneal fluid buildup
  • Malignant peritoneal effusion
  • Swollen belly

Peritoneal Effusion and Mesothelioma

Peritoneal effusion may be a symptom of peritoneal mesothelioma. Some research shows ascites in 60% – 100% of newly diagnosed peritoneal mesothelioma patients. This symptom may be one of the first things to make patients seek medical care.

Diagnostic tests may help doctors diagnose patients with ascites and, subsequently, peritoneal mesothelioma. Once a patient is diagnosed with mesothelioma, some treatments may seek to resolve peritoneal effusions. These treatments may help improve patients’ comfort and limit the recurrence of ascites.

02. Causes

Causes of Peritoneal Effusion

The most common cause of peritoneal effusion is liver disease (80%). The second most common is cancer (10%), which includes peritoneal mesothelioma. Other conditions like heart failure (3%) and tuberculosis (2%) can also cause ascites.

Peritoneal mesothelioma patients may develop ascites from fluid produced by aggressive tumors. This fluid accumulates in the abdominal cavity. If cancer cells migrate to the lymphatic system, they can block lymph drainage. This may also cause ascites.

Non-Cancerous Causes of Peritoneal Effusion

  • Cirrhosis (liver disease)
  • Dialysis
  • Heart failure
  • Pancreatic disease
  • Tuberculosis

Cancers That Cause Peritoneal Effusion

  • Breast cancer
  • Colon cancer
  • Liver cancer
  • Lung cancer
  • Ovarian cancer
  • Pancreatic cancer
  • Peritoneal mesothelioma

Peritoneal effusion symptoms may vary slightly depending on the cause. For example, malignant (cancerous) effusions may have cancer-related symptoms, like weight loss. Doctors can recommend the best course of treatment to address specific symptoms.

03. Symptoms

Symptoms of Malignant Peritoneal Effusion

Peritoneal effusion may cause a range of symptoms, including abdominal pain and nausea. For some patients, the symptoms of ascites may be the first step towards another diagnosis. People should seek medical care for stomach bloating that feels full and painful.

Symptoms of Peritoneal Effusion

  • Abdominal pain
  • Dyspnea (difficulty breathing)
  • Fatigue
  • Impaired movement
  • Loss of appetite
  • Lower limb swelling
  • Nausea
  • Vomiting

Common peritoneal mesothelioma symptoms may overlap with symptoms of ascites. Peritoneal mesothelioma symptoms include weight loss, a full abdomen, a general feeling of discomfort (malaise) and abdominal discomfort. Malignant peritoneal mesothelioma patients also report feeling overly full, nauseous or both.

As a patient’s underlying disease progresses, symptoms such as ascites may worsen. This may lead to increased abdominal discomfort. Talking with a healthcare provider at the onset of symptoms may help target the cause sooner. Some diseases, such as mesothelioma and other cancers, are more likely than others to lead to ascites.

04. Diagnosis

How Is Peritoneal Effusion Diagnosed?

Diagnosing ascites is an important first step in pinpointing the underlying condition. Doctors may use differential diagnosis to help rule out potential causes. This process may include cytology testing to screen for effusion-causing cancers, such as peritoneal mesothelioma, ovarian cancer and breast cancer.

The diagnosis of malignant peritoneal effusion may include any combination of the following:

  • Abdominal paracentesis (removal of fluid) followed by ascitic fluid analysis
  • Abdominal ultrasound
  • Blood tests
  • CT scan or other imaging tests
  • Fluid biopsy
  • Patient history
  • Physical examination
  • Tumor tissue biopsy

Doctors may order cancer screening tests to differentiate between peritoneal effusion and malignant peritoneal effusion. This may lead to a mesothelioma diagnosis.

Depending on patients’ symptoms, doctors may use various methods for treating ascites.

05. Treatment

How Is Peritoneal Effusion Treated?

Diuretics and paracentesis are the most common initial treatments for ascites. These methods can help treat and manage peritoneal effusions. Ascites may recur, resulting in patients receiving multiple rounds of drainage or other treatment. In some of these cases, palliative care options may also help ease discomfort.

Mesothelioma doctors may use different methods to treat peritoneal effusions, including:

  • Catheters and other drainage ports: Catheters are tubes that can allow fluid to drain out of the peritoneum. Some, such as shunts, can be implanted and used long-term. Some catheters go through the skin, draining fluid into an external container. And some drain fluid from the peritoneum into another area of the body. Doctors may also choose other types of drainage ports.
  • Diuretics: Doctors may prescribe medication that increases the frequency of urination. This has shown a reduction in peritoneal fluid buildup for some patients. Diuretics may be more effective against ascites caused by cirrhosis versus cancer.
  • Hyperthermic intraperitoneal chemotherapy (HIPEC): Doctors use a heated, localized chemotherapy to treat peritoneal mesothelioma in this method. The chemotherapy is heated to a temperature that kills cancer cells without killing healthy cells. Often HIPEC is combined with cytoreductive surgery.
  • Palliative HIPEC: This method uses heated chemotherapy alone, not in combination with surgery. For some patients, it has shown complete resolution of ascites and improvement in quality of life.
  • Paracentesis: In this method, doctors insert a needle into the abdominal cavity to drain the fluid buildup in the peritoneum. Paracentesis is the most common treatment for malignant peritoneal effusion. It is effective at relieving symptoms of abdominal discomfort, nausea, vomiting and breathing difficulty. This method provides temporary relief for 90% of patients. Symptoms may return quickly, so this method is frequently repeated.

For cancer patients, their mesothelioma treatments may also treat peritoneal effusions.

In 2019, researchers published a study about at-home drainage treatment. The study took place in 2011 at Memorial Sloan Kettering in New York. All 48 cancer patients received tunneled drainage catheters to treat ascites at home. Results showed an improvement in various factors, such as fatigue and other symptoms.

Reported Improvements From At-Home Drainage Treatment

  • Cognitive function
  • Difficulty breathing
  • Emotional function
  • Fatigue
  • Insomnia
  • Loss of appetite
  • Nausea and vomiting
  • Pain
  • Quality of life

When managing peritoneal effusions and underlying diseases, early detection, diagnosis and treatment matter. These factors may lead to patients having different prognostic and treatment options. Individuals experiencing symptoms of peritoneal effusion should speak to a healthcare provider for further guidance.

06. Common Questions

Common Questions About Peritoneal Effusion

What is the difference between ascites and normal peritoneal fluid?

Ascites happens when peritoneal fluid builds up beyond the normal amount. It can cause discomfort and bloating. The normal amount of peritoneal fluid differs with biological sex:

  • Male patients: Usually have very little
  • Female patients: May have up to 20 mL depending on hormonal changes

What causes free fluid to build up in the abdomen?

Free fluid buildup in the abdomen may be caused by:

  • In cancer cases: Tumor cells making a lot of protein, drawing fluid into the area
  • In cirrhosis cases: A cirrhosis symptom (portal hypertension) that can cause fluid to build
  • In cases of heart failure and kidney issues: Kidney cells retaining salt and water, causing fluid buildup

What is the life expectancy of a person with ascites?

Peritoneal effusion prognosis varies by root cause. Research shows patients with cirrhosis and ascites have a 5-year survival rate of about 30%. Survival for patients with cancer-related ascites depends on treatment and patient factors. More temporary causes are associated with better outcomes.