Rheumatoid lung disease w rheumatoid arthritis of unsp knee

This diagnosis code signifies a pulmonary manifestation of rheumatoid arthritis, specifically affecting the lung tissue, in a patient who also has rheumatoid arthritis impacting an unspecified knee joint. It indicates a systemic autoimmune disease with both articular (joint) and extra-articular (lung) involvement.

Apply this code when documentation clearly states a diagnosis of rheumatoid lung disease in a patient with rheumatoid arthritis of the knee, where the specific knee (right or left) is not documented. Supporting documentation would include physician notes detailing both the pulmonary findings consistent with rheumatoid lung disease (e.g., interstitial lung disease, nodules) and the diagnosis of rheumatoid arthritis affecting the knee.

• Ensure documentation specifies "rheumatoid lung disease" and not just a general lung condition in a patient with RA.
• If the specific knee affected is documented (e.g., right knee), a more specific code from the M05.16- subcategory should be used.
• This code should be sequenced after the primary rheumatoid arthritis code (e.g., M05.00-M05.9) if the lung disease is a manifestation of the underlying RA.