Written By: Karen Selby, RN,
Last modified: October 15, 2021

What Causes Peritoneal Effusions?

Approximately 85% of ascites cases are caused by cirrhosis of the liver, and roughly 10% of cases are caused by cancer. While the condition is relatively common among peritoneal mesothelioma patients, this cancer is a rare cause of peritoneal effusion overall.

Malignant ascites is typically associated with cancers of the colon, rectum, lung, pancreas, liver, ovary, uterus, breast or lymphatic system.

About 50% of malignant peritoneal effusions are caused by peritoneal carcinomatosis. This is when there are many small deposits of cancer in the peritoneal lining of the abdominal cavity. Roughly 13% are the result of other cancers spreading to the liver.

In peritoneal mesothelioma patients, malignant ascites may develop from:

  • Cancer cells migrating into lymph nodes and lymphatic channels, blocking the flow of fluid and resulting in fluid accumulation.
  • Aggressive tumors producing fluid that accumulates in the abdominal cavity.
  • Liver metastases that result in functional cirrhosis, which leads to a state called portal hypertension that causes ascites.

Peritoneal effusion isn’t strongly associated with survival time, but worsening ascites is a sign that the cancer is progressing.

Symptoms of Peritoneal Effusions

As fluid builds between the layers of the peritoneal lining, various symptoms may occur, including:

  • Abdominal pain
  • Abdominal swelling or distention
  • Trouble breathing
  • Chest pain
  • Weight gain
  • Nausea
  • Loss of appetite
  • Fatigue

Diagnostic Process

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. However, further testing is required to confirm fluid has indeed accumulated in the abdominal cavity.

Tools Used to Diagnose Peritoneal Effusion

  • Physical examination
  • Ultrasonography
  • CT scan
  • Testing fluid obtained via paracentesis (drainage of ascites fluid)

Imaging tests — such as ultrasonography and CT scans — can quickly indicate the presence of fluid around the abdomen.

When ascites is new to a patient or the cause is unknown, a paracentesis is ordered to drain the fluid and collect a sample to look for signs of cancer using pathology tests.

Mesothelioma Packet
Get a Free Peritoneal Mesothelioma Guide
Receive a peritoneal mesothelioma guide overnight. Learn about your diagnosis, top doctors and how to pay for treatment.


Treatment of malignant ascites is different from nonmalignant ascites.

While peritoneal effusion is a source of discomfort for people with peritoneal mesothelioma, it is treatable and controllable. Proper treatment can control pain and other symptoms in addition to resolving recurring ascites.

For patients with peritoneal mesothelioma, treatment of peritoneal effusion seeks to manage the buildup of fluid.

Treatment of ascites for peritoneal mesothelioma patients may include:

  • Therapeutic paracentesis
  • Placement of a permanent intraperitoneal catheter for ongoing drainage[/li]
  • Chemotherapy
  • Cytoreductive surgery and heated chemotherapy


A paracentesis is a minor surgical procedure that drains excess fluid from the abdomen using a hollow needle and a drainage tube that collects the fluid into a bag.

This procedure may be performed multiple times to control recurring ascites and associated symptoms such as distention, pain, nausea, vomiting and difficulty breathing.

Intraperitoneal Catheter

If severe cases of peritoneal effusions recur, your doctor may suggest the placement of a permanent intraperitoneal catheter.

Permanent catheters allow constant drainage of ascitic fluid, which relieves distension, pressure, pain, nausea, vomiting and difficulty breathing. Patients no longer have to return to the hospital for repeated paracenteses.

A minor surgical procedure in a hospital setting is required to place the catheter in the peritoneum. Small incisions in the abdomen are made to insert the catheter, which is then connected to a drainage tube.

The tube connects to a bag that collects the ascitic fluid. The bag is easily removed from the tube to allow nurses and patients to regularly dispose of accumulated fluid.

Patients and their caregivers are taught how to empty the bag and care for the catheter by a nursing staff before they go home. Some patients may have nurses come to their home to empty the bag and provide ongoing instruction until they are completely comfortable with the process.


Patients who opt to receive chemotherapy may notice a reduction of peritoneal effusion. When chemotherapy effectively kills mesothelioma cells, the tumors shrink. Fewer cancer cells means less fluid is produced.

However, ascites can recur when the cancer begins to grow again. A second or third line of chemotherapy can control recurring peritoneal effusions, especially in conjunction with a paracentesis or intraperitoneal catheter.

Cytoreductive Surgery and Heated Chemotherapy

Peritoneal mesothelioma patients who are diagnosed early enough to qualify for surgery also undergo hyperthermic intraperitoneal chemotherapy, also known as heated chemotherapy or HIPEC.

The surgery attempts to remove as much cancerous tissue as possible and is followed by localized chemotherapy that is heated to more efficiently kill any residual cancer cells that surgeons were unable to remove.

This approach is an effective way to control ascites because much of the cancer is removed or killed with chemotherapy, which greatly reduces the production of ascitic fluid.

Half of peritoneal mesothelioma patients who undergo surgery with heated chemotherapy live longer than five years, regardless of ascites or other symptoms. Approximately 40% of peritoneal mesothelioma patients qualify for surgery.

Is Mesothelioma a Cause of Your Peritoneal Effusions?

If you have a history of asbestos exposure and are experiencing recurring buildup of fluid in the lining of your abdomen, peritoneal mesothelioma may be the cause.

Peritoneal mesothelioma is very rare, with less than 600 cases diagnosed each year in the United States. The disease is frequently misdiagnosed as other abdominal cancers or less serious gastrointestinal conditions.

A paracentesis alone cannot diagnose malignant peritoneal mesothelioma. In many cases, no cancerous cells are found in the ascitic fluid. To get an accurate diagnosis, a tissue biopsy is obtained with either a fine-needle aspiration or a laparoscopic surgical biopsy.

If ascites persists, consider seeking a second opinion from a mesothelioma specialist.

Get the Compensation You Deserve
Older man viewing webinar on a laptop
Mesothelioma Case Value Webinar
Lab technician using a microscope in a lab
Immunotherapy & Mesothelioma Clinical Trials

Tell us what you think
Did this article help you?
How did this article help you?
What about this article isn’t helpful for you?
Did this article help you?

Thank you for your feedback. Would you like to speak with a Patient Advocate?