Undifferentiated inflammatory arthritis in a tuberculosis-positive patient: a diagnostic and therapeutic challenge - a case report.

Background: In clinical practice, some cases gently challenge our assumptions, reminding us that not everything is what it seems. This is the story of a young woman receiving treatment for tuberculosis who began showing signs that pointed beyond infection alone. It underlines how autoimmunity can surface in the shadows of another illness, demanding careful attention and an open mind.

Case presentation: A 27-year-old woman receiving treatment for pulmonary tuberculosis presented to us with worsening joint pain, swelling, facial rash, and muscle weakness. She had trouble with basic movements like climbing stairs and noticed rashes over her face and knuckles. On examination, she had a malar rash and Gottron's papules, with noticeably weakness in her upper and lower limbs. Her lab results showed elevated ESR and a positive PM-Scl antibody; meanwhile, other autoimmune markers were negative. Her imaging revealed tenosynovitis and microvascular changes on capillaroscopy. She was then diagnosed with undifferentiated inflammatory arthritis, within the myositis spectrum - and was started on steroids and DMARDs while continuing her TB therapy.

Discussion: This case highlights the challenges of diagnosing autoimmune disease in a patient already being treated for TB. In endemic areas, it is easy to blame new symptoms on infection alone, but her evolving clinical picture urged us to dig deeper. It reinforces the need for careful clinical judgment and teamwork when managing overlapping infectious and autoimmune conditions.

Conclusion: For patients like her, timely recognition of autoimmune features - especially in the context of chronic infections - can change outcomes. Her journey highlights not only the complexity of medicine but also the value of listening closely, thinking broadly, and responding with a multidisciplinary approach.