ICD-10 Code M05.449 – Rheumatoid myopathy with rheumatoid arthritis of unspecified hand (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.449 – Rheumatoid myopathy with rheumatoid arthritis of unspecified hand
What it is
This code identifies rheumatoid arthritis affecting an unspecified hand, with associated rheumatoid myopathy. It indicates inflammatory joint disease plus muscle involvement in the same hand.
Clinical signs
Clinical features vary; refer to documentation. You may see hand pain, swelling, stiffness, reduced range of motion, and weakness related to inflammatory muscle involvement.
When to use this code
Use this code when the record documents rheumatoid arthritis in an unspecified hand and specifically notes rheumatoid myopathy. Apply it when the provider links the muscle disorder to the rheumatoid condition. If laterality is not stated, do not assume right or left.
Do not use for
Do not use this code if the hand laterality is documented and a more specific code is available. Do not use it for isolated myopathy or rheumatoid arthritis without muscle involvement.
Coding tip
Check the note for both rheumatoid myopathy and hand laterality before assigning M05.449.