A51.49 vs M63
A51.49 (Other secondary syphilitic conditions) compared with M63 (Disorders of muscle in diseases classified elsewhere), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. M63 carries an Excludes1 note covering A51.49: “myopathy in secondary syphilis (A51.49)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| A51.49Other secondary syphilitic conditions | M63Disorders of muscle in diseases classified elsewhere | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | A00-B99 — Certain Infectious and Parasitic Diseases (A00-B99) | M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) |
| Definition | Other secondary syphilitic conditions is a billable ICD-10-CM diagnosis code (A51.49). | Disorders of muscle in diseases classified elsewhere is a non-billable ICD-10-CM category code (M63). |
| Includes | Secondary syphilitic lymphadenopathy Secondary syphilitic myositis | — |
| Code first | — | underlying disease, such as: leprosy (A30.-) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources