Myelitis in diseases classified elsewhere

This code describes inflammation of the spinal cord (myelitis) that is a manifestation or complication of another underlying disease process. It indicates that the myelitis itself is not the primary diagnosis but rather a secondary condition resulting from a separate, specified illness.

Apply this code when documentation clearly links myelitis to an underlying systemic disease, infectious process, or autoimmune condition. Examples include myelitis secondary to lupus, sarcoidosis, or HIV. The medical record must explicitly state the causal relationship between the primary disease and the myelitis.

• Always sequence the underlying disease first, followed by this code to indicate the manifestation.
• Ensure the documentation specifies the "diseases classified elsewhere" to support the use of this manifestation code.
• Do not use this code for primary or idiopathic myelitis; instead, refer to codes within G04.-.