What Is Peritonitis?

Medically Reviewed by Jabeen Begum, MD on November 14, 2023
5 min read

Peritonitis is inflammation of the peritoneum, the tissue that lines the inner wall of your abdomen and covers and supports most of your abdominal organs. Peritonitis is usually caused by infection from bacteria or fungi.

If left untreated, peritonitis can rapidly spread infection to the blood. That can cause sepsis, a condition that can lead tomultiple organ failure and death. So, if you develop any of the symptoms -- the most common of which is severe abdominal pain -- you should call your doctor. If you have severe abdominal pain after an accident or injury, call 911 or get to an emergency department to prevent potentially fatal complications.

Doctors split peritonitis into several types. These include:

  • Spontaneous bacterial peritonitis. This is when bacteria start growing in the abdominal lining. It’s most common in people with liver disease and those with kidney failure getting dialysis through a tube in their abdominal lining.
  • Secondary peritonitis. This is when an infection spreads to the lining from elsewhere. It can happen, for example, when there’s a hole in your stomach or intestines, or when your appendix bursts. This is the most common type.
  • Sterile peritonitis. Sometimes, you can get peritonitis without an infection. That can happen if irritating fluids leak from your gallbladder, pancreas, stomach, or elsewhere in your body. This may also be called chemical peritonitis.


The first symptoms of peritonitis are often poor appetite, nausea, and a dull belly ache. The dull ache can quickly turn into persistent, severe abdominal pain that gets worse when you move.

Other signs and symptoms may include:

If you get peritoneal dialysis, symptoms also may include:

  • Cloudy dialysis fluid
  • White flecks, strands, or clumps in the dialysis fluid

The most common causes of spontaneous bacterial peritonitis (SBP) include:

  • Liver disease with cirrhosis (scarring), and a buildup of abdominal fluid, called ascites. The fluid can get infected. Other conditions that cause fluid buildup, such as kidney disease, heart failure, and certain cancers, also can lead to peritonitis.
  • Peritoneal dialysis for kidney failure. Germs can get into the catheter tube placed in your peritoneum to move fluids in and out of your body and remove waste products from your blood. Feeding tubes also can cause direct infections of the abdominal lining.

 Causes of secondary peritonitis can include:

  • A ruptured appendix
  • Stomach ulcers
  • Digestive diseases such as Crohn's disease and diverticulitis
  • An inflamed pancreas
  • Pelvic inflammatory disease
  • Holes in your stomach, intestines, or gallbladder
  • Surgery
  • Injuries from knife wounds, gunshots or accidents
  • Punctures from endoscopy or colonoscopy (medical tests in which viewing tubes enter the throat or rectum), although these are rare events.

Causes that don't involve infection can include:

  • Bile leaking from an inflamed gallbladder
  • Acid leaking from your stomach after an ulcer causes a hole
  • Enzymes leaking from an inflamed pancreas
  • A ruptured tumor or cyst


If you have any symptoms of peritonitis, call your doctor right away. The doctor will ask about your symptoms and medical history, and do a thorough physical examination. They'll check for tension and tenderness in your belly.

You may get some tests, including:

  • Blood tests to look for infection and inflammation
  • Imaging tests, such as X-rays and CT scans, to look for holes and tears in your digestive tract
  • Exploratory surgery to find out what's causing your problems

Your doctor also may perform a paracentesis, a procedure to take fluid from the abdominal cavity with a thin needle. The test can check for infection and may relieve some pressure if you have fluid buildup in your belly.

If you're diagnosed with peritonitis, you'll be admitted to a hospital. Typically, you'll immediately start intravenous antibiotics or antifungal medications to treat the infection. You'll need more treatments if signs of sepsis or other complications appear. Such treatments may include intravenous fluids and drugs to maintain blood pressure.

You might also get pain medication and oxygen. Some people need blood transfusions.

If you have peritonitis caused by peritoneal dialysis, you may get medications injected directly into the abdominal cavity.

Many people need emergency surgery, especially if their peritonitis is caused by conditions such as appendicitis, a stomach ulcer, or diverticulitis. The infected tissue and any part of the peritoneal tissue seriously damaged by infection will be surgically removed.

In the hospital, you will be closely watched for signs of sepsis and septic shock. You might be transferred to an intensive care unit.

Does peritonitis go away?

With fast treatment, peritonitis usually goes away. But you could have lingering complications, such as organ damage.

Some people who have ascites (fluid built up in their bellies because of liver damage) might get antibiotics to prevent peritonitis. It's not clear, though, that the practice works.

People getting dialysis through a tube in their abdomens also can take steps to prevent peritonitis.

If you're getting peritoneal dialysis, you should:

  • Thoroughly wash your hands, including the areas between your fingers and under your fingernails, before touching the catheter.
  • Wear a mouth/nose mask during your fluid exchanges.
  • Inspect each bag of solution for signs of contamination, such as cloudiness, before you use it.
  • Find a clean, dry, well-lit place to do your treatments.
  • Apply an antibiotic cream to the catheter exit site every day.
  • Store your supplies in a cool, clean, dry place.

Immediately report any possible contamination of your dialysis fluid or catheter to your dialysis nurse. In many cases, a single dose of antibiotics can prevent contamination from turning into an infection. Such infections are less common than they once were because of improved equipment and safety practices.

Peritonitis can lead to complications, including:

  • Sepsis. The infection can get into your bloodstream and trigger inflammation throughout your body, potentially leading to organ failure and death.
  • Dehydration . As fluid builds up in the belly, the rest of your body may get too little fluid.
  • Constipation. You may have trouble pooping because your organs are temporarily paralyzed.
  • Scar tissue. Inflammation may cause scar buildup that can block your bowels.
  • Kidney failure. This can happen when people with liver disease develop a condition called hepatorenal syndrome, which affects blood flow to the kidneys. The only cure is a liver transplant.
  • Repeat infections. Sometimes, peritonitis comes back after the original cause is treated.