9 Min Read
Last Updated: 05/20/2024
Fact Checked

Written by Karen Selby, RN | Medically Reviewed By Dr. Rupesh Kotecha | Edited By Walter Pacheco

Key Facts About Peritoneal Effusion
  • Cirrhosis is the most common cause of peritoneal effusions, accounting for 80% of cases.
  • Cancer is the second most common cause of ascites, with about 10% of cases.
  • There are different types of ascites, including malignant and infectious.
  • Recent research shows hyperthermic intraperitoneal chemotherapy (HIPEC) can successfully treat recurrent and malignant peritoneal effusions.

What Is Peritoneal Effusion?

Peritoneal effusion, also called ascites, is an abnormal buildup of fluid in the peritoneal cavity. This peritoneal fluid can accumulate in the abdomen, leading to abdominal distention (a swollen belly), pain and other symptoms. The peritoneum is the thin membrane of tissue that lines the inside of the abdominal cavity. 

Certain medical conditions can cause fluid to cross this membrane and collect in the abdomen. Peritoneal effusion is common in peritoneal mesothelioma patients. Peritoneal effusion isn’t associated with mesothelioma survival rates, but worsening ascites is a sign of cancer progression.

A diagram showing where peritoneal effusion occurs.
What is Peritoneal Effusion?

There are several ways to describe different types of peritoneal effusions. Ascites can be uncomplicated and easily treated, or it can be refractory, meaning it’s resistant to treatment. Peritoneal effusions can also be classified based on their cause. For example, cancer causes malignant peritoneal effusions.

Ascites can also be described based on protein levels in the peritoneal fluid. An exudate is peritoneal fluid with a high protein level, while a transudate is fluid with a low protein level. This information can help doctors determine the cause of peritoneal effusion.

What Causes Peritoneal Effusions?

Many conditions, including liver disease, cancer and infections, can cause peritoneal effusions. Liver cirrhosis is the most common cause of ascites. Cirrhosis can cause portal hypertension, or high blood pressure in the veins that enter the liver, which can force fluid into the abdominal cavity.

Cancer is the second most common cause of peritoneal effusions. It can cause ascites in several different ways. Metastases or primary tumors of the peritoneum can produce fluid. Metastases to the lymph nodes can block the normal flow of lymph fluid. Liver metastases can cause cirrhosis-like problems that lead to ascites.

Causes of Peritoneal Effusions and Percentage of Cases
  • Cirrhosis (about 80%)
  • Cancer (about 10%)
  • Heart failure (about 3%)
  • Tuberculosis (about 2%)
  • Other (about 2%)
  • Dialysis (about 1%)
  • Pancreatic disorder (about 1%)

Less common causes of peritoneal effusions include heart failure, kidney failure, pancreatitis, tuberculosis, low protein levels in the blood and bacterial peritonitis — an infection of the peritoneum.

Continued Learning

Asbestos-Related Diseases

Symptoms of Peritoneal Effusions

Peritoneal effusion is one of many signs and symptoms of mesothelioma. Ascites is reported in more than half of all cases of peritoneal mesothelioma but can also occur with other types of mesothelioma that have spread to the abdomen.

Abdominal symptoms of peritoneal effusions are the most common, including pain, swelling, bloating, nausea and loss of appetite. Weight gain can occur because of fluid retention in the abdomen.

Symptoms of Peritoneal Effusion
  • Abdominal pain
  • Abdominal swelling or distention
  • Chest pain
  • Fatigue
  • Loss of appetite
  • Nausea
  • Swollen ankles
  • Trouble breathing
  • Weight gain

Peritoneal effusion is always a sign of an underlying condition. Symptoms can vary based on the severity of the ascites and the underlying cause.

Trina presented to me with unexplained ascites (excess abdominal fluid). We did an exploratory laparotomy and multiple peritoneal biopsies for an angry looking peritoneum. The pathological diagnosis turned out to be abdominal mesothelioma.

How Is Peritoneal Effusion Diagnosed?

Doctors diagnose peritoneal effusion based on the results of a physical exam, imaging scans and laboratory analysis of the peritoneal fluid. Ascites is among the first diagnoses that will come to a doctor’s mind when a patient goes to the doctor with severe abdominal distension.

Imaging tests, such as ultrasonography and CT scans, can show the presence of peritoneal fluid in the abdomen. If fluid is present, doctors need to collect a liquid biopsy to make a diagnosis.

A gloved hand is holding a microscope slide stained pink to identify cancer cells.
A needle biopsy from a peritoneal effusion can reveal details on cancer cell type.

A procedure called paracentesis is used to drain ascites fluid and collect a biopsy for analysis. The sample is analyzed in a pathology lab to determine the type of peritoneal effusion and to look for potential cancer cells. This process is known as cytology.

According to a 2022 study, cytology testing of ascites fluid can detect malignant mesothelioma about 34% of the time. This is why doctors typically rely on tissue biopsies to ensure an accurate diagnosis of mesothelioma.

Treating Peritoneal Effusions

Treatment for nonmalignant peritoneal effusions involves draining excess fluid and taking steps to prevent further fluid accumulation. For malignant ascites, this can involve chemotherapy. Managing pain and other symptoms is also part of treatment.

Mesothelioma treatments can help address pleural effusions or ascites and prevent recurrent effusions.


Paracentesis for mesothelioma is a minor surgical procedure that involves draining fluid through a long, blunt needle inserted into the abdominal cavity. Draining the fluid can relieve acute symptoms but needs to be repeated if ascites returns.

Large volumes of fluid can accumulate in the abdomen with ascites. A recent study shows that removing 5 liters or more of ascites fluid requires an infusion of albumin to maintain proper protein and electrolyte levels in the blood.

Intraperitoneal Catheter

For severe, recurring ascites, a permanent intraperitoneal catheter can be surgically placed in the abdomen. This allows for constant drainage of peritoneal effusion fluid through a tube attached to the catheter.

This minor surgical procedure involves inserting the catheter into the peritoneal space through small incisions in the abdomen. In addition to relieving symptoms, an intraperitoneal catheter eliminates the need for repeated paracentesis.


Chemotherapy can improve malignant peritoneal effusions by killing the cancer cells responsible for producing ascites fluid. Ascites can recur when the cancer begins to regrow. A second or third line of chemotherapy can control recurring peritoneal effusions. 

The Journal of Surgical Oncology published a 2023 study of patients with malignant ascites. Researchers found that combining inpatient ascites drainage with chemotherapy and supplemental nutrition improved patient outcomes.

Cytoreductive Surgery and Heated Chemotherapy

Surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) is an effective treatment to control malignant ascites. Cytoreductive surgery removes cancerous tumors, and chemotherapy infused into the abdominal cavity kills the remaining cells. This greatly reduces the production of ascitic fluid.

A 2023 study in the Journal of Obstetrics and Gynaecology showed that HIPEC combined with the drug bevacizumab improved malignant ascites more than HIPEC alone. Another chemotherapy technique called pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is currently undergoing clinical trials. It is expected to improve clinical outcomes, especially in patients ineligible for surgery and HIPEC.

Is Mesothelioma a Cause of Your Peritoneal Effusions?

If you have recurring peritoneal effusions and prior asbestos exposure, mesothelioma may be the cause. Malignant mesothelioma of all types can cause peritoneal effusions. This includes not only peritoneal mesothelioma but also pleural, pericardial and other types of mesothelioma.

Peritoneal mesothelioma is rare, with less than 600 cases diagnosed each year in the United States. It is commonly misdiagnosed as another type of abdominal cancer or a less serious gastrointestinal condition. Remember, paracentesis alone is not sufficient to diagnose malignant peritoneal mesothelioma. A tissue biopsy is needed to confirm the presence of cancerous cells.

Persistent or recurrent ascites can be a sign of mesothelioma or other cancer. Consider seeking a second opinion from a mesothelioma specialist for persistent peritoneal effusions.

Survivor Story
Jayda K. Default Subtitle

Recurrent Ascites Leads to Peritoneal Mesothelioma Diagnosis

Survivor Story

“As a young woman with abdominal pain, I had a really hard time convincing someone I was in pain. A really hard time. I was told it was just my period,” Jayda said. Her doctors finally did a laparoscopy. Her peritoneal effusion turned out to be more than a gallon of fluid and the surgeon saw growths on her peritoneum. A biopsy confirmed her peritoneal mesothelioma diagnosis.

Read Jayda’s Story

Common Questions About Peritoneal Effusions

Can peritoneal effusions be prevented?

Yes, you can take steps to prevent liver disease and cancer, but that does not guarantee that you will not develop these conditions. A healthy lifestyle can lower your risk of cancer and liver cirrhosis. This includes avoiding alcohol, tobacco and recreational drugs, getting regular exercise, eating a healthy diet, limiting salt intake and practicing safe sex.

What are the complications associated with peritoneal effusions?

Peritoneal effusions can cause many serious complications. Fluid buildup in the abdomen can put pressure on abdominal organs and the chest. Persistent ascites fluid in the abdomen can lead to infection, such as spontaneous bacterial peritonitis.

Complications of peritoneal effusions

  • Abdominal hernias
  • Abdominal pain
  • Difficulty breathing
  • Fluid in the lungs
  • Kidney failure
  • Risk of infection

Controlling ascites and treating the underlying cause can help prevent these complications.

Are there any risk factors for developing peritoneal effusions?

Several medical conditions can significantly increase your risk of developing ascites.

Risk factors for peritoneal effusions

  • Abdominal infections
  • Abdominal or pelvic cancer
  • Alcohol abuse
  • Autoimmune hepatitis
  • Congestive heart failure
  • Genetic liver diseases
  • Hepatitis B or C
  • Kidney failure
  • Nonalcoholic fatty liver disease

Conditions that lead to liver cirrhosis are the biggest risk factors for ascites. Certain cancers, infections, heart failure or kidney failure also greatly increase the risk of developing peritoneal effusions

How long does it take to recover from peritoneal effusions?

Many symptoms of peritoneal effusions typically improve immediately after draining ascites fluid. Uncomplicated peritoneal effusions — without infection, cancer, or liver disease — respond well to treatment. Refractory peritoneal effusions, on the other hand, are recurrent and do not respond well to treatment.

Treatment for recurrent ascites can last for many months, requiring repeated procedures. Multiple rounds of chemotherapy may be needed to control malignant ascites.

Can peritoneal effusions recur?

Yes, peritoneal effusions can, and often do, recur. Depending on the underlying cause, ascites can return days to months after successful treatment. In the case of malignant ascites, recurrent peritoneal effusions can be a sign of worsening cancer.

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