2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Diseases Of The Respiratory System 460-519 > Acute Respiratory Infections 460-466 > ICD-9-CM Diagnosis 463 Acute tonsillitis Inflammation of the tonsils, especially the palatine tonsils. It is often caused by a bacterium. Tonsillitis may be acute, chronic, or recurrent. 463 is a specific code that can be used to specify a diagnosis 463 contains 6 index entries