Peritonitis from Bowel Perforation
Perforation of GI tract (from lower esophagus to colon) can result in a peritonitis as seen here at autopsy.
www-medlib.med.utah.edu/WebPath/GIHTML/GI036.html   reviews

Peritonitis Graphics and Discussion
Case study of a 70-year-old male with peritonitis.
path.upmc.edu/cases/case60.html   reviews