Peritonitis - spontaneous

Alternative names
Spontaneous bacterial peritonitis (SBP)

Peritonitis is an inflammation of the peritoneum, which is the membrane that lines the wall of the abdomen and covers the organs. Spontaneous peritonitis is an infection that occurs as a complication of ascites (a collection of fluid in the peritoneal cavity), which is usually related to liver or kidney failure.

Causes, incidence, and risk factors

Most cases of bacterial peritonitis occur:

  • When fluid accumulates in the peritoneal cavity (ascites) because of chronic liver disease.  
  • In kidney failure patients undergoing peritoneal Dialysis. In these patients, the cause of spontaneous peritonitis is infection in the blood that spreads to the peritoneal fluid, usually from a contaminated peritoneal Dialysis catheter.

Risk factors for liver disease include alcoholic Cirrhosis and other diseases that lead to Cirrhosis, such as viral hepatitis. Patients with kidney failure can develop nephrotic syndrome, which leads to ascites and can then become infected.

Spontaneous peritonitis is rare in children.


  • Fluid in the abdomen  
  • Abdominal pain and distention  
  • Tenderness  
  • Decreased bowel sounds  
  • Inability to pass feces or gas  
  • Fever  
  • Thirst  
  • Low urine output

Additional symptoms that may be associated with this disease:

Signs and tests
Tests that show infection:

  • Culture of peritoneal fluid  
  • Chemical examination of peritoneal fluid  
  • Peritoneal fluid analysis( paracentesis)  
  • Cytologic examination (cell studies) of peritoneal fluid  
  • Blood culture

Other tests that may be performed:

  • Abdominal imaging studies (to rule out other causes of Abdominal pain)  
  • Laparotomy exploratory  
  • WBC (nuclear) scan


Treatment depends on the cause of the peritonitis. Surgery may be needed in cases where peritonitis is asociated with a foreign object, such as a Peritoneal dialysis catheter. Antibiotics are administered to control infection in cases of spontaneous peritonitis in patients with liver or kidney disease, and dehydration is treated by intravenous therapy.

Hospitalization is common and may be necessary to rule out other causes of peritonitis such as appendicitis and diverticulitis.

Expectations (prognosis)

The infection can usually be treated, but the outcome may be poor because of underlying kidney or liver disease. People with these conditions often respond to antibiotics but may still have a poor outcome.


  • Abscess development  
  • Intestinal obstruction from scar tissue  
  • Hepatorenal syndrome  
  • Hepatic encephalopathy  
  • Massive sepsis

Calling your health care provider

Call your health care provider if you have symptoms of peritonitis; this can quickly become an emergency situation!


In patients with peritoneal catheters, sterile techniques should be closely followed. In cases of liver failure, antibiotics may be used to prevent recurrences of peritonitis.

Johns Hopkins patient information

Last revised: December 8, 2012
by Armen E. Martirosyan, M.D.

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