Is it possible to have peritonitis with out an infection present?
Yes might have, Peritonitis simply means inflammation of the peritoneum. Whilst an infection can cause this, other issues such as an perforated appendix, perforated bowel, gall bladder issues or other substances from other organs can leak into the abdominal cavity causing this inflammation too. Your cyst might have pushed on other organs causing a spillage into the abdominal cavity for example.