Mycobacterium-Induced Reactive Arthritis in an Older Adult With Rheumatoid Arthritis.

The use of immunosuppressive medications to treat rheumatoid arthritis may trigger the activation of latent mycobacteria, leading to infection. These infections can lead to reactive arthritis. Conversely, both reactive and rheumatoid arthritis may be encountered in the geriatric population. When such complications arise, the treatment process becomes more complicated, necessitating careful consideration of elaborate therapeutic approaches. An 83-year-old man presented to our hospital with subacute back pain and arthralgia of the extremities. The patient was diagnosed with rheumatoid arthritis combined with mycobacterial arthritis. We approached the treatment cautiously by concurrently managing tuberculosis and non-tuberculous mycobacteria (NTM), and administering methotrexate and prednisolone for rheumatoid arthritis. This treatment resulted in remission of both conditions. When treating arthritis in older adults, it is important to consider the possibility of reactive arthritis secondary to mycobacterial infection and rule out latent tuberculosis. Moreover, when rheumatoid arthritis is complicated by mycobacterial infection and during the management of rheumatoid arthritis, the possibility of arthritis exacerbation due to mycobacteria should be considered. Hence, in situations where there is a likelihood of extrapulmonary lesions stemming from Mycobacterium infection, a proactive treatment approach targeting both Mycobacterium spp. and rheumatoid arthritis is indispensable.