Neurology & Pain Management Coding Alert

Question: I have encounter notes in front of me that indicate the provider treated a patient with, according to the encounter form, "rheumo lung disease w/knee RA." Could you decipher this phrase for me, and how many diagnosis codes would I need for this condition?

California Subscriber

Answer: While this is just an informed guess, your provider was probably referring to a patient with rheumatoid lung disease, accompanied by rheumatoid arthritis (RA) of the knee. Go back and check with the provider just to be sure, but patients that suffer RA often also suffer from some rheumatoid disease, such as rheumatoid lung disease. ICD-10 has codes that combine these conditions, such as:

• M05.161 - Rheumatoid lung disease with rheumatoid arthritis of right knee
• M05.162 - Rheumatoid lung disease with rheumatoid arthritis of left knee
• M05.169 - Rheumatoid lung disease with rheumatoid arthritis of unspecified knee.

Do this: Go back and check the notes to see if you can get any more information on the laterality of the RA. If you cannot get a definitive laterality answer, opt for M05.169.

Some other knee-related RA ICD-10 codes include:

• M05.06- - Felty's syndrome, knee
• M05.16- - Rheumatoid lung disease with rheumatoid arthritis of knee 
• M05.26- - Rheumatoid vasculitis with rheumatoid arthritis of knee
• M05.36- - Rheumatoid heart disease with rheumatoid arthritis of knee
• M05.46- - Rheumatoid myopathy with rheumatoid arthritis of knee
• M05.56- - Rheumatoid polyneuropathy with rheumatoid arthritis of knee
• M05.66- - Rheumatoid arthritis of knee with involvement of other organs and systems.

In addition to the M05.06- code set, ICD-10 also lists several more diagnosis categories for different types of rheumatoid arthritis (RA): RA with involvement of other organs or systems, RA with rheumatoid factor, etc. Each of these RA code sets includes a diagnosis for RA of the knee.