DefinitionPeritonitis is swelling (inflammation) of the peritoneum -- the tissue that lines the wall of the abdomen and covers the abdominal organs.Alternative NamesSpontaneous bacterial peritonitis (SBP)Causes, incidence, and risk factorsSpontaneous peritonitis is usually caused by ascites, a collection of fluid in the peritoneal cavity. This usually occurs from liver or kidney failure.Risk factors for liver disease include alcoholic cirrhosis and other diseases that lead to cirrhosis, such as viral hepatitis (Hepatitis B or C).Spontaneous peritonitis also occurs in patients who are on dialysis for kidney failure.SymptomsAbdominal painand bloatingAbdominal tendernessFeverFluid in the abdomenLow urine outputOther symptoms include:ChillsJoint painNausea and vomitingSigns and testsTests that