Acute appendicitis with peritoneal abscess

This code represents an acute inflammation of the appendix that has progressed to form a localized collection of pus within the peritoneal cavity. This indicates a more severe and complicated form of appendicitis.

Use this code when documentation clearly states acute appendicitis accompanied by a peritoneal abscess. This typically occurs when the appendix has ruptured or perforated, leading to localized infection. Supporting documentation would include operative reports detailing an appendectomy and the presence of an abscess, or imaging reports confirming both conditions.

• Differentiate from acute appendicitis without abscess (540.9) or with generalized peritonitis (540.0).
• Ensure the documentation specifies "peritoneal abscess" and not just "abscess" if the location is unclear.
• Consider sequencing if other complications or conditions are also present, prioritizing the most severe or treated condition.