Peritonitis is a serious condition that starts in the abdomen. That's the area of the body between the chest and the pelvis. Peritonitis happens when the thin layer of tissue inside the abdomen becomes inflamed. The tissue layer is called the peritoneum. Peritonitis usually happens due to an infection from bacteria or fungi.

There are two types of peritonitis:

• Spontaneous bacterial peritonitis. This infection is caused by bacteria. It can happen when someone has liver disease, such as cirrhosis, or kidney disease.
• Secondary peritonitis. Peritonitis can happen due to a hole, also called a rupture, inside an organ in the abdomen. Or it can be caused by other health conditions.

It's important to get treatment fast for peritonitis. Health care providers have ways to clear out the infection. They also can treat any medical problem that might be causing it. Peritonitis treatment usually involves medicines that are used for infections caused by bacteria, called antibiotics. Some people with peritonitis need surgery. If you don't get treatment, peritonitis can lead to a serious infection that spreads through the body. It can be deadly.

A common cause of peritonitis is a treatment for kidney failure called peritoneal dialysis. This treatment helps get rid of waste products from the blood when the kidneys struggle to do that job themselves. If you get peritoneal dialysis, you can help prevent peritonitis with good hygiene before, during and after dialysis. For example, it's important to wash your hands and clean the skin around your catheter.

Symptoms of peritonitis include:

• Belly pain or tenderness.
• Bloating or a feeling of fullness in the abdomen.
• Fever.
• Upset stomach and vomiting.
• Loss of appetite.
• Diarrhea.
• Reduced urine.
• Thirst.
• Not able to pass stool or gas.
• Feeling tired.
• Confusion.

If you get peritoneal dialysis, peritonitis symptoms also may include:

• Cloudy dialysis fluid.
• White flecks, strands or clumps — which are called fibrin — in the dialysis fluid.

When to see a doctor

Peritonitis can be life-threatening if you don't get treatment quickly. Call your health care provider right away if you have severe pain or tenderness of your abdomen, bloating or a feeling of fullness along with:

• Fever.
• Upset stomach and vomiting.
• Reduced urine.
• Thirst.
• Not able to pass stool or gas.

If you get peritoneal dialysis, call your health care provider right away if your dialysis fluid:

• Is cloudy or has an unusual color.
• Has white flecks in it.
• Has strands or clumps in it.
• Smells unusual, especially if the area around your catheter is changes color or is painful.

Peritonitis also might happen after a burst appendix or a serious injury to your abdomen

• Get medical help right away if you have severe belly pain. It may feel so bad that you can't sit still or find a comfortable position.
• Call 911 or get emergency medical care if you have severe belly pain after an accident or injury.

Peritoneum infection is usually caused by a hole in an organ in the abdomen, such as the stomach and colon. The hole is also called a rupture. It's rare for peritonitis to happen for other causes.

Common causes of a hole that leads to peritonitis include:

• Medical procedures
  • Peritoneal dialysis uses tubes, also called catheters, to remove waste products from the blood. An infection may happen during peritoneal dialysis due to an unclean treatment room, poor hygiene or tainted equipment.
  • Peritonitis also may happen after digestive surgery.
  • Use of feeding tubes can lead to peritonitis.
  • Peritonitis can happen after a procedure to take out fluid from your abdomen, such as for the condition ascites in liver disease.
  • In rare cases, it can be a complication of an exam to check inside the rectum and colon called colonoscopy.
  • Peritonitis can happen after a procedure to check the digestive tract called endoscopy. This is also rare.
• A ruptured appendix, stomach ulcer or hole in the colon. Any of these conditions can allow bacteria to get into the peritoneum through a hole in your digestive tract.
• Pancreatitis. This is inflammation of a gland in the abdomen called the pancreas. If you have pancreatitis and you get an infection, bacteria could spread outside the pancreas. That may lead to peritonitis.
• Diverticulitis. Infection of small, bulging pouches in the digestive tract may cause peritonitis. This could happen if one of the pouches breaks open. The burst pouch could spill waste from the intestine into the abdomen.
• Trauma. Injury may cause peritonitis. This could allow bacteria or chemicals from other parts of the body to get into your peritoneum.

Peritonitis that happens without a hole or tear is called spontaneous bacterial peritonitis. It's usually a complication of liver disease, such as cirrhosis. Advanced cirrhosis causes a lot of fluid buildup in your abdomen. That fluid buildup could lead to a bacterial infection.

Some things that raise the risk of peritonitis are:

• Peritoneal dialysis. Peritonitis can happen in people who get this treatment.
• Other medical conditions. Certain conditions raise your risk of getting peritonitis, such as:
  • Liver cirrhosis.
  • Appendicitis.
  • Stomach ulcers.
  • Diverticulitis.
  • Crohn's disease.
  • Pancreatitis.
• History of peritonitis. Once you've had peritonitis, your risk of getting it again may be higher than that of someone who's never had it.

Without treatment, peritonitis may cause a whole-body infection called sepsis. Sepsis is very dangerous. It can cause shock, organ failure and death.

Peritonitis that's linked with peritoneal dialysis is often caused by germs around the catheter. If you use peritoneal dialysis, take these steps to prevent peritonitis:

• Wash your hands before you touch the catheter. Scrub under your fingernails and between your fingers.
• Clean the skin around the catheter with an antiseptic every day.
• Store your supplies in a clean place.
• Wear a surgical mask during your dialysis fluid exchanges.
• Talk with your dialysis care team about the correct care for your peritoneal dialysis catheter.

Your health care provider may prescribe antibiotics to prevent peritonitis, especially if you've had peritonitis before. Antibiotics also might be prescribed if you have a buildup of peritoneal fluid due to a medical condition such as liver cirrhosis. If you take medicine called a proton pump inhibitor, you may be asked to stop taking it.

To diagnose peritonitis, your health care provider talks with you about your medical history and gives you a physical exam. Your symptoms alone may be enough for your provider to diagnose the condition if your peritonitis is linked to peritoneal dialysis.

If more tests are needed to confirm a diagnosis, your health care provider may suggest:

• Blood tests. A sample of your blood may be taken to see if you have an increase in disease-fighting white blood cells. This is usually a sign of an infection or inflammation. You also might have a blood culture test to find out if bacteria are in your blood.
• Imaging tests. You may have an X-ray exam to check for holes or other tears in your digestive tract. You also may have a test that uses sound waves to make images inside your body, called ultrasound. In some cases, you may have a CT scan.
• Peritoneal fluid analysis. In this test, a thin needle is used to take a sample of the fluid in your peritoneum. You're more likely to have this test if you get peritoneal dialysis or if you have fluid in your abdomen from liver disease. An increased white blood cell count in this fluid usually points to an infection or inflammation. A culture of the fluid may be used to spot bacteria.

Spontaneous bacterial peritonitis can be life-threatening. You'll need to stay in the hospital. Treatment includes antibiotics. It also includes supportive care to ease your symptoms.

You'll also need to stay in the hospital for secondary peritonitis. Treatment may include:

• Antibiotics. You'll likely take antibiotic medicine through a needle in a vein. This clears out the infection and keeps it from spreading. The type of antibiotic you'll need and how long you'll have to take it will vary. It depends on how serious your condition is and the kind of peritonitis you have.
• Surgery. This is often needed to remove infected tissue, treat the cause of the infection, and prevent the infection from spreading. Surgery is important if your peritonitis is due to a ruptured appendix, stomach or colon.
• Other treatments. Depending on your symptoms, your treatment while in the hospital will likely include:
  • Pain medications.
  • Fluids given through a tube, called intravenous fluids.
  • Oxygen.
  • In some cases, a blood transfusion.

If you get peritoneal dialysis

If you have peritonitis, your health care provider may suggest that you receive dialysis in another way. You may need this other type of dialysis for several days while your body heals from the infection. If your peritonitis lingers or comes back, you may need to stop having peritoneal dialysis completely and switch to a different type of dialysis.