ICD-10 Code M05.179 – Rheumatoid lung disease with rheumatoid arthritis of unspecified ankle and foot (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M05.179 – Rheumatoid lung disease with rheumatoid arthritis of unspecified ankle and foot
What it is
This code identifies rheumatoid arthritis affecting an unspecified ankle and foot, with associated rheumatoid lung disease. Use it when the record links both the joint disease and lung involvement to rheumatoid arthritis.
Clinical signs
Documentation may show inflammatory ankle or foot arthritis plus pulmonary findings attributed to rheumatoid disease. Clinical features vary; refer to documentation for the specific lung manifestation and joint laterality details.
When to use this code
Use this code when the provider documents rheumatoid lung disease together with rheumatoid arthritis involving an ankle and foot, and the site is not further specified. It fits cases where the ankle and foot are affected, but side is not recorded. Confirm that the lung disease is explicitly associated with rheumatoid arthritis.
Do not use for
Do not use it if the lung condition is unrelated to rheumatoid arthritis or if the arthritis involves a different joint. If the ankle or foot side is documented, check whether a more specific code applies.
Coding tip
Always verify two elements in the note: rheumatoid lung disease and unspecified ankle/foot involvement.