The peritoneum is a silk-like membrane that lines your inner abdominal wall and covers the organs within your abdomen. Peritonitis is a bacterial or fungal infection of this lining. The infection may come from fluid buildup within the peritoneum, from another infection, inflammation or injury within your body, or it may be a complication of peritoneal dialysis.  

If peritonitis is left untreated, the infection can extend beyond your peritoneum. Bacteria from peritonitis may infect your bloodstream (bacteremia) and once there, cause the infection to spread throughout your body (sepsis). Sepsis is a rapidly progressing, life-threatening condition that can cause shock and organ failure.

Infection of the peritoneum can happen for a variety of reasons. Here are the most common causes of peritonitis:

  • Peritoneal dialysis. Dialysis removes waste products and extra fluid from your blood when your kidneys can no longer do so. With peritoneal dialysis, the network of tiny blood vessels in your abdomen (peritoneal cavity) is used to filter your blood. Peritonitis is the most common complication associated with peritoneal dialysis. An infection may occur during peritoneal dialysis due to unclean surroundings, poor hygiene or contaminated equipment.
  • Fluid buildup. Diseases that cause liver damage, such as cirrhosis, can result in a large amount of fluid buildup in your abdominal cavity (ascites). That fluid buildup is susceptible to bacterial infection. This type of peritonitis is called spontaneous peritonitis.

Secondary peritonitis
When other medical conditions result in an infection that causes peritonitis, it’s referred to as secondary peritonitis. These causes include:

  • A ruptured appendix, stomach ulcer or perforated colon. Any of these conditions can allow bacteria to get into the peritoneum through a hole in your gastrointestinal tract.
  • Pancreatitis. Inflammation of your pancreas (pancreatitis) complicated by infection may lead to peritonitis if the bacteria spread outside the pancreas.
  • Diverticulitis. Infection of small, bulging pouches in your digestive tract (diverticulitis) may cause peritonitis if one of the pouches ruptures, spilling intestinal waste into your abdomen.
  • Crohn’s disease. Bowel wall inflammation is common in people who have Crohn’s disease. This inflammation may cause the bowel to rupture, spilling its contents and causing peritonitis.
  • Trauma. Injury or trauma may cause peritonitis by allowing bacteria or chemicals from other parts of your body to enter the peritoneum.
Factors that increase your risk of peritonitis include:
Peritoneal dialysis. Peritonitis is common among people undergoing peritoneal dialysis.
Other medical conditions. The following medical conditions increase your risk of developing peritonitis: cirrhosis, appendicitis, Crohn’s disease, stomach ulcers, diverticulitis, pancreatitis.
History of peritonitis. Once you’ve had peritonitis, your risk of developing it again is higher than it is for someone who has never had peritonitis.
Signs and symptoms of peritonitis include: 

  • Abdominal pain or tenderness
  • Bloating or a feeling of fullness in your abdomen (distention)
  • Fever
  • Nausea and vomiting
  • Low urine output
  • Thirst
  • Inability to pass stool or gas
  • Chills

If you’re receiving peritoneal dialysis, peritonitis symptoms also include:

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

To treat peritonitis, your doctor will likely prescribe an antibiotic medication to fight the infection and prevent it from spreading. The type and duration of your antibiotic therapy depend on the severity of your condition and the kind peritonitis you have.

You may need to be hospitalized for peritonitis that’s caused by infection from other medical conditions (secondary peritonitis). Surgery is often necessary to remove infected tissue, treat the underlying cause of the infection and prevent the infection from spreading.
If you’re undergoing peritoneal dialysis and you have peritonitis, your doctor may recommend you receive dialysis in another way for several days while your body heals from the infection. If peritonitis persists or recurs, you may need to stop having peritoneal dialysis entirely and switch to a different form of dialysis.

If you’re receiving peritoneal dialysis, take the following steps to prevent peritonitis:

  • Wash your hands before touching the catheter
  • Clean the area around the catheter with antiseptic every day
  • Store your supplies in a cool, clean place

If you’ve had spontaneous peritonitis before, or if you have peritoneal fluid buildup due to a medical condition such as cirrhosis, your doctor may prescribe antibiotics to prevent peritonitis.