One of the complications of diverticulitis can be the formation of an abscess in the abdominal cavity. The inflammation or infection can then reach the abdominal wall and causes peritonitis. This infection can also spread to other parts of the body such as organs near the intestine, causing sepsis, which is dangerous. In addition, a fistula may form between the intestine and other organs. Diverticulitis may also cause a blockage in the colon.