Generalized (acute) peritonitis

This code represents a widespread inflammation of the peritoneum, the membrane lining the abdominal cavity and covering its organs, that has an acute onset. It signifies a severe, often life-threatening condition resulting from infection or irritation that has spread throughout the abdominal cavity.

Use this code when documentation clearly indicates an acute, diffuse inflammation of the entire peritoneal lining. This typically arises from a ruptured organ (e.g., appendix, diverticulum), trauma, or widespread infection. Supporting documentation should specify "generalized" or "diffuse" peritonitis, and often include terms like "acute abdomen" or "septic peritonitis."

• Differentiate from localized peritonitis (e.g., K65.1), which affects only a specific area.
• Always code the underlying cause of the peritonitis first, if known and documented (e.g., ruptured appendix, perforated ulcer).
• Look for documentation of systemic inflammatory response syndrome (SIRS) or sepsis, and code these conditions additionally if present.