Peritonitis is caused by a collection of blood, body fluids, or pus in the abdomen. There are two types of peritonitis:
Spontaneous peritonitis is most often caused by an infection in fluid that collects inside the abdomen.
The fluid buildup tends to occur with advanced liver or kidney disease, and in people who are on peritoneal dialysis for kidney failure. It can also be due to inflammation, infection, or injury of the intestines.
Secondary peritonitis occurs due to another condition in the body, such as an infection that spreads from the digestive tract caused by a ruptured appendix, a stomach ulcer, diverticulitis, or a perforated colon, for instance.
Injuries like gunshot or knife wounds can also bring about the infection, as well as the use of dialysis catheters or feeding tubes.
Peritonitis caused by bacteria can also develop into sepsis, which is a very serious infection of the bloodstream.
Premature babies who have underdeveloped organs (necrotizing enterocolitis) may also be susceptible to secondary peritonitis.