Peritonitis is inflammation of the peritoneum — a silk-like membrane that lines your inner abdominal wall and covers the organs within your abdomen — that is usually due to a bacterial or fungal infection. There are two types of peritonitis: Spontaneous bacterial peritonitis. Sometimes, peritonitis develops as a complication of liver disease, such as cirrhosis, or of kidney disease. Secondary peritonitis. Peritonitis can result from rupture (perforation) in your abdomen, or as a complication of other medical conditions.