Rheumatoid myopathy with rheumatoid arthritis of unsp site

This code signifies a muscular disorder (myopathy) directly caused by rheumatoid arthritis, affecting an unspecified anatomical location. It describes muscle weakness, pain, or dysfunction that is a direct manifestation or complication of the underlying autoimmune inflammatory process of rheumatoid arthritis.

Apply this code when documentation clearly indicates a diagnosis of rheumatoid myopathy in a patient with rheumatoid arthritis, and the specific muscle group or body region affected by the myopathy is not specified. This is appropriate when the physician explicitly links the myopathy to the rheumatoid arthritis.

• Always sequence the underlying rheumatoid arthritis code (e.g., M05.xx or M06.xx) first, followed by this code.
• Avoid using this code if the myopathy is due to medication side effects (e.g., corticosteroids) or other unrelated causes; instead, code the specific myopathy.
• If the site of the rheumatoid myopathy is known, use a more specific code from the M05.4- subcategory.