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What is Peritonitis?

Your abdomen, also called your midsection or belly, is the part of your body that contains your organs including your stomach, small and large intestine, and liver. These organs are protected by the abdominal wall, a layer of tough tissue under your skin. On the inside of the abdominal wall is another thin layer of tissue called the peritoneum [peh-ree-tohn-EE-um].

Peritonitis [peh-ree-tuhn-EYE-tis] is a condition where the peritoneum becomes inflamed. This is usually caused by an infection from bacteria or fungus, but can also be caused by fluids leaking into your abdomen from other organs like the liver.

Usually, peritonitis is caused by an infection that gets into your peritoneum because of a rupture (rip or tear) in the abdominal wall. Some other types of peritonitis can happen even without a rip are:

  • Spontaneous bacterial peritonitis. This kind of peritonitis happens when there is a bacterial infection inside your body that spreads to the peritoneum.
  • Secondary peritonitis. This can be caused by bacteria inside your body that spread to the peritoneum, or chemicals released into your body by other organs like a leaky intestine.


The symptoms of peritonitis can be different from person to person. The most common symptom is a lot of pain in your abdomen that gets worse when you move or if someone touches you there. Other symptoms include:

  • Bloated abdomen
  • Fever
  • Feeling sick or vomiting
  • Not having any appetite to eat or drink
  • Diarrhea
  • Low urine output
  • Feeling very thirsty
  • Not able to use the bathroom
  • Feeling tired

When to See a Doctor

Peritonitis is a very serious illness, and you should see a doctor right away if you think you might have it. Without medical care, the infection in your abdomen can spread to other parts of your body, including your organs and/or bloodstream.


Peritonitis is usually caused by an infection in the peritoneum that makes it inflamed. 

This infection often happens because of a hole in the digestive tract. Your stomach, small intestine, large intestine, and colon process food and drink, turning it into nutrients and waste products. These organs also safely digest bacteria that can cause infection. If one of these organs has a hole in it, the food or waste can leak out into the other parts of your body like the peritoneum, making you sick.

A hole in your digestive organs can be caused by:

  • Tubes or catheters [KATH-ih-turs]Feeding tubes can help you eat if you have an illness that makes it hard to chew, swallow, or digest food. Catheters can take waste out of your body if you can’t walk to go to the bathroom or don’t have control over that part of your body. Both of these create a hole in your digestive organs that can sometimes leak.
  • Diverticulitis [DYE-vuhr-TIK-you-LI-tis]. Your digestive tract has small pouches that can get infected and burst. If this happens, waste can get into your abdomen, spreading the infection to your peritoneum.
  • Trauma. Your abdomen can be punctured because of accidents, like falling on something sharp or a car crash, or because of violence, like being shot in the abdomen or stabbed with a knife.

Other causes of peritonitis include:

  • Bile or other chemicals.  Your liver makes bile, a fluid that helps break down fats in the food you eat. Bile is a normal part of your digestive system, but it can leak into your abdomen and inflame other organs, including your peritoneum.
  •  Sepsis. Sepsis is an infection in your bloodstream that can spread to your abdomen and other parts of your body.

Diagnosis and Tests

If your doctor thinks you have peritonitis, they will do a physical exam to look for symptoms. During this exam, they might also ask you questions about your medical history, including:

  • If you’ve had recent injuries that could have caused an infection
  • If you are recovering from any other illness
  • If you are having dialysis

Sometimes, your doctor might need to do more tests to check for peritonitis and rule out other conditions that can have similar symptoms.  Some of these tests include:

  • Blood tests. A lab can check how many white blood cells there are in your blood. A high count of these cells can mean you have an infection.
  • Imaging tests. Tests like x-rays, ultrasounds, or CT scans can be used to take pictures or videos of the inside of your body and look for holes in your abdomen.
  • Peritoneal fluid analysis. The fluid inside your peritoneum can be checked in a lab to check for infection or other illnesses.


Treatments for peritonitis include:

  • Antibiotics. An antibiotic is a medicine that can fight the infection and stop it from spreading through your peritoneum or other parts of your body.
  • Surgery. You might need surgery to remove infected tissue and repair the part of the abdomen that has the hole.
  • Other treatments. Your doctor might use other treatments to help you with the pain or other symptoms of peritonitis while you are sick. These can include pain medicine, fluids, oxygen, and blood transfusion.


You can lower your chance of getting peritonitis by taking steps to avoid situations that could cause injury or infection to your abdomen. Some of these include:

  • Drive safely. Car accidents are a major cause of injury and can cause damage to your abdomen and organs, including rips that can let harmful bacteria into your peritoneum.
  • Dialysis hygiene. If you are getting dialysis for another condition, you should take steps to make sure you don’t get an infection around the dialysis site. Wash your hands before touching the catheter, clean the skin around it every day, and wear a surgical mask when you’re exchanging dialysis fluids.
Peritonitis [PEH-ree-TUHN-eye-TIS] is a condition where the peritoneum, the thin layer of tissue inside your abdomen, becomes inflamed. This is usually caused by an infection from bacteria or fungus, but can also be caused by fluids leaking into your abdomen from other organs like the liver.