The term “acute abdomen” is used to indicate the presence of any of a wide variety of abdominal disorders causing severe abdominal pain.

An acute abdomen is usually accompanied by peritonitis, an inflammation of the peritoneum (the membrane lining the abdominal cavity). Peritonitis is usually caused by contents of a ruptured organ, such as the digestive juices and food from the stomach, fecal material from an intestine, urine from the bladder, bile from the liver, or pus from a ruptured appendix (appendicitis).

It can also result from internal bleeding, disease, or contamination from an open abdominal wound. Peritonitis is always a danger with an open abdominal wound and often results from a closed abdominal injury.