What Causes Peritoneal Effusions?

Cirrhosis of the liver causes approximately 85% of peritoneal effusion cases, and cancer causes roughly 10% of cases. The condition is common among peritoneal mesothelioma patients.

Certain cancers have an association with malignant ascites. They include cancers of the colon, rectum, lung, pancreas, liver, ovary, uterus, breast or lymphatic system.

Peritoneal carcinomatosis causes about 50% of malignant peritoneal effusions. It involves small deposits of cancer in the 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. This blocks 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. This leads to a state called portal hypertension that causes ascites.

Peritoneal effusion isn’t associated with survival time. But, worsening ascites is a sign of cancer progression.

Symptoms of Peritoneal Effusions

As fluid builds between the layers of the peritoneal lining, various symptoms occur.

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

Diagnostic Process

Doctors perform physical examinations, imaging scans and testing ascites, to diagnose peritoneal effusion. 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.

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 show the presence of fluid around the abdomen.

A paracentesis drains the fluid and collects a sample to look for signs of cancer using pathology tests.

A study of cytology testing of peritoneal effusions detected cancerous cells in 34% of samples. Pleural effusions revealed cancer cells in 64% of samples. A 2022 study published these results in Cytopathology.


Treatment of malignant ascites involves cancer treatments such as chemotherapy. Nonmalignant ascites treatment involves draining fluid.

Peritoneal effusion is treatable and controllable. Proper treatment controls pain and other symptoms besides resolving recurring ascites.

Treatment seeks to manage the buildup of fluid for patients with peritoneal mesothelioma.

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. It drains excess fluid from the abdomen using a hollow needle and a drainage tube.

Repeat procedures control recurring ascites and associated symptoms.

Intraperitoneal Catheter

Doctors suggest the placement of a permanent intraperitoneal catheter for severe, recurring cases.

Permanent catheters allow constant drainage of ascitic fluid. This 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 places the catheter in the peritoneum. The catheter goes into small incisions in the abdomen, which is then connected to a drainage tube.


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 production.

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

Surgery and heated chemotherapy is an effective treatment to control ascites. It removes cancer and kills the remaining cells with chemotherapy. This greatly reduces the production of ascitic fluid.

Half of the surgery patients 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 recurring effusions and prior asbestos exposure, peritoneal mesothelioma may be the cause.

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

A paracentesis alone cannot diagnose malignant peritoneal mesothelioma. A tissue biopsy must confirm the presence of cancerous cells.

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