Diverticulitis is the condition where a colonic diverticulum ruptures causing a small perforation, which is usually self-contained and forms a little abscess. Most patients with diverticulitis have pain and fever and can have nausea and vomiting as well. Sometimes this can be treated as an outpatient with antibiotics, but sometimes hospitalization is required. It is unknown why diverticulitis occurs in some patients, but once treated, it does not usually occur again.