2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Digestive System 520-579 > Appendicitis 540-543 > ICD-9-CM Diagnosis 541 Appendicitis unqualified Acute inflammation of the APPENDIX. Acute appendicitis is classified as simple, gangrenous, or perforated. 541 is a specific code that can be used to specify a diagnosis 541 contains 10 index entries